EP3766089A1 - Porous ceramic for electrolytes used in thin-film electrochemical devices - Google Patents

Abstract

The invention relates to a thin-film electrolyte in an electrochemical device such as a lithium-ion battery, said electrolyte comprising a porous inorganic layer impregnated with a phase carrying lithium ions, characterized in that said porous inorganic layer has an interconnected network of open pores.

Description

 POROUS CERAMIC FOR ELECTROLYTES USED IN THIN-FILM ELECTROCHEMICAL DEVICES

Technical field of the invention

 The invention relates to the field of electrochemistry, and more particularly the electrochemical systems in thin layers. More specifically, it relates to thin film electrolytes useful in electrochemical systems such as high power batteries (especially lithium ion batteries) or supercapacitors. The invention relates more particularly to an electrolyte comprising a porous inorganic layer impregnated with a phase carrying lithium ions and a process for preparing such a thin-layer electrolyte. The invention also relates to a method of manufacturing an electrochemical device comprising at least one such electrolyte, and the devices thus obtained.

State of the art

 A lithium ion battery is an electrochemical component that stores electrical energy. In general, it is composed of one or more elementary cells, and each cell comprises two electrodes of different potentials and an electrolyte. Various types of electrolytes can be used in lithium ion secondary batteries. A cell may comprise two electrodes separated by a polymeric porous membrane (also called "separator") or a porous ceramic membrane impregnated with a liquid electrolyte containing a lithium salt.

By way of example, patent application JP 2002-042792 describes the production of an electrolyte layer on an electrode of a battery. The targeted electrolytes are essentially polymeric membranes such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride whose pores are impregnated with a lithium salt such as LiPF ₆ . According to the teaching of this document, the size of the electrophoretically deposited particles should preferably be less than 1 μm, and the layer formed preferably has a thickness of less than 10 μm. In such a system, the liquid electrolyte migrates both into the porosities contained in the membrane and towards the electrodes and thus ensures the ionic conduction between the electrodes.

In order to make thin-film batteries of high power and to reduce the resistance to transport of the lithium ions between the two electrodes, it has been sought to increase the porosity of the polymeric membrane. However, the increase in the porosity of the polymeric matrices facilitates the precipitation of lithium metal dendrites in the pores of the polymeric membrane during the charge and discharge cycles of the battery. These dendrites are the cause of internal short circuits within the cell which can induce a risk of thermal runaway of the battery. It is known that these polymer membranes impregnated with a liquid electrolyte have a lower ionic conductivity than the liquid electrolyte used. In order to facilitate the ionic conduction between the electrodes and the electrolyte, thin polymeric membranes have been employed. However, these polymeric membranes are mechanically fragile and can have their electrical insulation properties altered by the effect of strong electric fields as is the case in batteries charged with electrolyte films of very thin thickness, or under effect of mechanical and vibratory stresses. These polymeric membranes tend to break during charge and discharge cycles, causing the detachment of anode and cathode particles, inducing electrical insulation losses causing short-circuits between the two positive and negative electrodes, which can lead to dielectric breakdown. This phenomenon is accentuated in batteries using porous electrodes.

 To improve the mechanical strength, Ohara proposed, in particular in the patent application EP 1049188 A1 and the patent EP 1 424 743 B1, to use electrolytes composed of a polymer membrane containing glass-ceramic particles conducting lithium ions.

Moreover, it is known from Maunel et al. (Polymer 47 (2006) p.5952-5964) that the addition of ceramic fillers in the polymer matrix makes it possible to improve the morphological and electrochemical properties of the polymeric electrolytes; these ceramic fillers can be active (such as Li ₂ N, UAI ₂ O ₃ ), in which case they participate in the lithium ion transport process, or be passive (such as Al ₂ O ₃ , SiO ₂ , MgO), in which case they do not participate in the process of transporting lithium ions. Particle size and characteristics of ceramic fillers affect the electrochemical properties of electrolytes, see Zhang et al., "Flexible and ion-conducting membrane electrolytes for solid-state lithium batteries: Dispersions of garnet nanoparticles in insulating POE," NanoEnergy, 28 (2016) p.447-454. However, these membranes are relatively fragile and break easily under the effect of mechanical stresses induced during assembly of the batteries.

The present invention seeks to remedy at least in part the disadvantages of the prior art mentioned above.

More specifically, the problem that the present invention seeks to solve is to provide electrolytes having a high ionic conductivity, a stable mechanical structure, good thermal stability, a long life, and which do not pose a safety problem. Another problem that the present invention seeks to solve is to provide a method for manufacturing such a thin-layer electrolyte that is simple, safe, fast, easy to implement, easy to industrialize and inexpensive.

 Another object of the invention is to provide electrolytes for batteries capable of operating reliably and without risk of fire.

 Another problem is to provide an electrolyte which has no organic binder, because such a binder can, in case of internal short circuit of the battery, cause and feed a fire.

 Another object of the invention is to provide a rigid structure battery having a high power density capable of mechanically withstanding shocks and vibrations.

Another object of the invention is to provide a method of manufacturing an electronic, electrical or electrotechnical device such as a battery, a capacitor, a supercapacitor comprising an electrolyte according to the invention.

 Another object of the invention is to provide devices such as batteries, lithium ion battery cells, capacitors, supercapacitors with increased reliability and having a long life and can be encapsulated by deposited coatings. by the atomic layer deposition technique (ALD, Atomic Layer Deposition), at elevated temperature and under reduced pressure.

Yet another object of the invention is to propose devices such as batteries, lithium ion battery cells, capacitors, supercapacitors, capable of storing a high energy density, to restore this energy with a very high energy density. high power density (especially in capacitors or supercapacitors), withstand high temperatures, have a long life and can be encapsulated by coatings deposited by ALD at high temperature and under reduced pressure.

Objects of the invention

According to the invention the problem is solved by the use of at least one thin film electrolyte in an electrochemical device such as a lithium ion battery, said electrolyte comprising a porous inorganic layer having an interconnected network of impregnated open pores a phase carrying lithium ions. Preferably, the porous inorganic layer has a mesoporous structure whose porosity is greater than 25% by volume, preferably greater than 30% by volume. Advantageously, the open pores of said porous inorganic layer have an average diameter D ₅ o less than 100 nm, preferably less than 80 nm, preferably between 2 nm and 80 nm, and even more preferably between 2 nm and 50 nm, and a volume greater than 25% of the total volume of said thin-layer electrolyte, and preferably greater than 30%.

 Advantageously, the open pores of said porous inorganic layer have a volume of between 30% and 50% of the total volume of said thin-film electrolyte.

Preferably, said porous inorganic layer is free of organic binder.

 Advantageously, the thickness of the electrolyte in a thin layer is less than 10 μm, preferably between 3 μm and 6 μm, and preferably between 2.5 μm and 4.5 μm.

Advantageously, said porous inorganic layer comprises an electronically insulating material, preferably chosen from Al ₂ O ₃ , SiO ₂ , ZrO ₂ , and / or a material selected from the group consisting of:

o garnets of formula Li _d A \ A ² _y (T0 ₄ ) z where

^■ A ¹ is a cation of oxidation + II, preferably Ca, Mg, Sr, Ba, Fe, Mn, Zn, Y, Gd; and or

^■ A ² represents a cation with an oxidation number + III, preferably Al, Fe, Cr, Ga, Ti, La; and or

^■ ₍₄ T0) represents an anion wherein T is an atom with an oxidation number + IV, located at the center of a tetrahedron formed by the oxygen atoms, and wherein T0 ₄ advantageously is the anion silicate or zirconate , knowing that all or part of the elements T of a degree of oxidation + IV can be replaced by atoms of a degree of oxidation + III or + V, such as Al, Fe, As, V, Nb, In , Ta;

^■ knowing that: d is between 2 and 10, preferably between 3 and 9, and even more preferably between 4 and 8; x is between 2.6 and 3.4 (preferably between 2.8 and 3.2); y is from 1.7 to 2.3 (preferably from 1.9 to 2.1) and z is from 2.9 to 3.1;

garnet, preferably chosen from: Li ₇ La ₃ Zr ₂ 0i ₂ ; Li _{6 2 2} bata 0i _2; Li _5,5 Li ₃ Nbi _{, 75} ln _{0 25} Oi ₂ ; Li ₅ La ₃ M ₂ 0i ₂ with M = Nb or Ta or a mixture of two compounds; U _7-x Ba _{x 3-x} M ₂ O ₁₂ with 0 <x <1 and M = Nb or Ta or a mixture of the two compounds; Li _7-x La ₃ Zr _2-x M _x O ₁₂ with 0 <x <2 and M = Al, Ga or Ta or a mixture of two or three of these compounds;

lithiated phosphates, preferably chosen from: lithium-type phosphates of the NaSICON type, Li ₃ PO ₄ ; LiPO ₃ ; Li ₃ AI _0.4 Sci _{, 6} (PO ₄ ) ₃ called "LASP"; Li 1 _, Zn _{, 9} Cao _, (PO ₄ ) ₃ ; LiZr ₂ (PO ₄ ) ₃ ; U 1 _{+ 3 x} Zr ₂ (P _{x x} Si _x O ₄ ) ₃ with 1, 8 <x <2.3; the ϋi _{+ 6c} ZG2 (Ri-cB _c q4) 3 with 0 <x <0.25; Li3 (Sc ₂ -xM _x ) (P0) 3 with M = AI or Y and 0

<x <1; Li 1 _{+ x} M _x (Sc) 2-x (PO 4) 3 with M = Al, Y, Ga or a mixture of the three compounds and 0 <x <0.8; Li 1 _{+ x} M _x (Ga 1-y S y) 2-x (PO ₄ ) 3 with 0 <x 0.8; 0 £ y <1 and M = Al or Y or a mixture of the two compounds; Li 1 _{+ x} M _x (Ga) _2-x (PO ₃ ) with M = Al, Y or a mixture of the two compounds and 0 <x <0.8; Li _{1 + x} Al _x Ti 2-x (PO ₄ ) ₃ with 0 <x <1 called "LATP"; or Lii _{+ x} AlxGe ₂ -x (P0) 3 with 0 <x <1 called "LAGP"; or Lii _{+ x + z} Mx (Gei-yTiy) 2-xSizP3-zOi2 with 0 <x <0.8 and 0 <y <1, 0 and 0 <z <0.6 and M = Al, Ga or Y or a mixture of two or three of these compounds; Li _{3 + y} (Sc 2-x M x) Q _y P 3- _y O 12 with M = Al and / or Y and Q = Si and / or Se, 0 <x <0.8 and 0 <y <1; or Li 1 _{+ x + y} M _x Sc 2- _x QyP 3- _y O 12 with M = Al, Y, Ga or a mixture of the three compounds and Q = Si and / or Se, 0 <x <0.8 and 0 <y <1; or Li 1 _{+ x + y + z} M _x (Ga 1- _y Sc _y ) ₂ -x Q ₂ P ₃ -zO ₂ with 0 <x <0.8, 0 <y <1, 0 <z <0.6 with M = Al or Y or a mixture of the two compounds and Q = Si and / or Se; or ϋi _{+ c} ZG ₂ - XB _X (P0 ₄ ) 3 with 0 <x <0.25; or Li 1 _{+ x} Zr 2- _x Ca _x (PO 4) 3 with O <x <0.25; or U _{I + X} M ³ _X M2- _X P30 _I 2 with 0 <x <1 and M ³ = Cr, V, Ca, B, Mg, Bi and / or Mo, M = Sc, Sn, Zr, Ht, Se or Si, or a mixture of these compounds;

the lithiated borates, preferably chosen from: Li ₃ (Sc 2-xMx) (B0 3) 3 with M = Al or Y and O <x <1; Li 1 _{+ x} M _x (Sc) 2 _x (B0 3) 3 with M = Al, Y, Ga or a mixture of the three compounds and 0 <x <0.8; Ui _{+ x} Mx (Gai-yScy) 2-x (B03) 3 with 0 <x <0.8, 0

<y <1 and M = Al or Y; Li 1 _{+ x} M _x (Ga) 2 _x (B0 3) 3 with M = Al, Y or a mixture of the two compounds and 0 <x <0.8; the U3BO3 the U3BO3-U2SO4, Li _3-B03 Li2Si04, U _{3-B03-Li2Si04} Li2S04 j

the oxynitrides, preferably chosen from ϋ ₃ R0 ₄ -cN 2c / 3, U ₄ SiO _{4- x} N 2x / 3, Li ₄ GeO ₄ -xN 2x / 3 with 0 <x <4 or U 3 BO 3 -XN 2 X / 3 with 0 <x <3;

lithiated compounds based on lithium oxynitride and phosphorus, called "LiPON", in the form of Li _x POyN _z with x ~ 2.8 and 2y + 3z ~ 7.8 and 0.16 <z <0.4 , and in particular Li _{2 9PO3,} 3N _0.4 6 but also the Li _w PO _x NYS _z compounds with 2x + 3y + 2z = 5 = w or _w Li _x PO _y S _z N compounds with 3, 2 <x <3.8, 0.13 <y <0.4, 0 <z <0.2, 2.9 <w <3.3 or the compounds in the form of UP _x AlyO _u N _v S _w with 5x + 3y = 5, 2u + 3v + 2w = 5 + t, 2.9 <t <3.3, 0.84 <x <0.94,

0.094 <y <0.26, 3.2 <u <3.8, 0.13 <v <0.46, 0 <w <0.2;

materials based on phosphorus or boron lithium oxynitrides, known as "LiPON" and "LIBON", respectively, which may also contain silicon, sulfur, zirconium, aluminum, or a combination of aluminum, boron , sulfur and / or silicon, and boron for phosphorus lithium oxynitride materials;

the lithiated compounds based on lithium oxynitride, phosphorus and silicon called "LiSiPON", and in particular Li1 9Si0 28P1OO1 1 N1 0; o lithium oxynitrides of LiBON, LiBSO, LiSiPON, LiSON, thio-LiSiCON, LiPONB (or B, P and S respectively represent boron, phosphorus and sulfur);

o lithium oxynitrides of LiBSO type such as (1 -x) LiBO ₂ -xLi ₂ S0 with 0.4

<x <0.8;

o the lithiated oxides, preferably chosen from Li ₇ La ₃ Zr ₂ 0i ₂ or Li _{5 + x} La ₃ (Zr _x , A _2-x ) Oi ₂ with A = Sc, Y, Al, Ga and 1, 4 <x <2 or Lio _, Lao _{, 55} Ti0 ₃ or Li _3x La _2/3-x Ti0 ₃ with 0 <x <0.16 (LLTO);

the silicates, preferably chosen from Li ₂ Si ₂ O ₅ , Li ₂ SiO ₃ , Li ₂ Si ₂ O ₆ , LiAISiO ₄ , Li ₄ SiO ₄ , LiAISi ₂₀ O;

solid electrolytes of anti-perovskite type chosen from: Li ₃ OA with a halide or a mixture of halides, preferably at least one of F, Cl, Br, I or a mixture of two or three or four of these elements; Li _(3-x) M _{x / 2} OA with 0 <x <3, M a divalent metal, preferably at least one of Mg, Ca, Ba, Sr or a mixture of two or three or four of these elements, a halide or a mixture of halides, preferably at least one of F, Cl, Br, I or a mixture of two or three or four of these elements; Li ₍ 3 _x) M ³ _{x / 3} OA with 0 <x <3, M ³ a trivalent metal, A halide or a mixture of halides, preferably at least one of F, a mixture of two or three or four of these elements; or LiCOX and Y of the halides as mentioned above in relation to the compounds Lao _, if I-Iio _, Ti _{2, g 4} , Li _{3 4} Vo _{, 4} Geo _{, 6} O ₄ , Li ₂ O-Nb ₂ 0 _4;

the formulations based on Li ₂ CO ₃ , B ₂ O ₃ , Li ₂ O, Al (PO ₃ i ₂ S, Li ₃ N, LiI ₄ Zn (GeO ₄ ) ₄ , Li _{3 6} Geo _{, 6} Vo _{, 4} 0 ₄ , LiTi ₂ (PO ₄ ) ₃ , ,, ₂₅ Po _{, 25} S ₄

Lii _{, 3} Alo _, 3Tii _{, 7} (P0 ₄ ) ₃ , ϋi _{+ c} AI _c M ₂ - _c (R0 ₄ ) ₃ (where M = Ge, Ti, and / or Hf, and where 0 <x <1), Lii _{+ x + y} Al _x Ti _2-x SiyP ₃ -yOi 2 (where 0 <x <1 and 0 <y <1).

Advantageously, said pores of the thin-film electrolyte are impregnated with a phase carrying lithium ions, such as an organic solvent or a mixture of solvents in which at least one lithium salt is dissolved, and / or a polymer containing at least one lithium salt, and / or an ionic liquid or a mixture of ionic liquids, possibly diluted with a suitable solvent, containing at least one lithium salt. Advantageously, said pores of the electrolyte are impregnated with a phase carrying lithium ions comprising at least 50% by weight of at least one ionic liquid. Said porous inorganic layer may be made of electrolyte material (or may comprise such a material), that is to say of a material in which the lithium ions have a sufficient mobility. Said porous inorganic layer may consist of a material (or may include such a material) which has neither an electronic conductivity nor an ionic conductivity sufficient for lithium ions. In both cases the electrolyte layer is formed by said porous inorganic layer and by said lithium ion carrier phase with which it has been impregnated. In the second case, it is this lithium ion carrier phase which alone ensures the ionic conductivity in the electrolyte, whereas in the first case the mobility of the lithium ions within the material of the porous inorganic layer contributes to the ionic conductivity.

 Said carrier phase of lithium ions must comprise lithium ions. To form this carrier phase, the lithium ions can be dissolved in any suitable solvent. By way of example, said lithium ion carrier phase may comprise an ionic liquid, possibly diluted with a suitable solvent. It may also include a polymer, which may be dissolved with a suitable solvent, which may be liquid or at least sufficiently viscous to invade the open porosity of the porous inorganic layer.

According to the invention, said porous inorganic layer can be deposited by electrophoresis, by the ink-jet printing process (called "ink-jet" in English), by scraping (called "doctor blade" in English), by coating. roll (called "roll coating" in English), by curtain coating (called "curtain coating" in English) or by the dip coating process (called "dip-coating" in English), from a colloidal suspension of nanoparticles of an electronically insulating material or a solid electrolyte material. Preferably, it does not contain a binder. According to an essential characteristic of the invention, this suspension comprises aggregates or agglomerates of primary nanoparticles.

 Said primary nanoparticles forming aggregates or agglomerates are preferably monodisperse, that is to say their primary diameter has a narrow distribution. This allows a better control of the porosity, and a fortiori of the mesoporosity.

The heat treatment leads to the partial coalescence of the nanoparticles of material (phenomenon called "necking"), knowing that the nanoparticles have a high surface energy which is the driving force for this structural modification; the latter occurs at a temperature much lower than the melting point of the material, and after a relatively short treatment time. Thus a three-dimensional mesoporous structure is created presenting an interconnected network of open pores, in one piece, free of binder, in which the lithium ions have a mobility that is not slowed down by grain boundaries or binder layers. This partial coalescence of aggregated nanoparticles allows the transformation of aggregates into agglomerates. The partial coalescence of the agglomerated nanoparticles induced by the heat treatment allows the consolidation of the three-dimensional mesoporous structure.

This structure also gives good mechanical strength of the layer itself without binder.

The aggregates or agglomerates, respectively, can also be obtained directly after hydrothermal synthesis if the suspension is not sufficiently purified: the ionic strength of the suspension then leads to the aggregation or agglomeration of the primary nanoparticles to form particles. aggregated, respectively agglomerated, of larger size.

A second subject of the invention is a method of manufacturing a thin-film electrolyte deposited on an electrode, said layer preferably being free of organic binder and preferably having a porosity, preferably mesoporous, greater than 30% by volume. , and even more preferably between 30% and 50% by volume, and said layer having pores with an average diameter D ₅ o of less than 100 nm, preferably less than 80 nm and preferably less than 50 nm, said method being characterized by what:

 (a) supplying a colloidal suspension comprising aggregates or agglomerates of nanoparticles of at least one inorganic material, said aggregates or agglomerates having a mean diameter of between 80 nm and 300 nm (preferably between 100 nm and 200 nm),

 (b) supplying an electrode,

 (c) depositing on said electrode a porous inorganic layer by electrophoresis, by the process of ink jet printing, scraping, roll coating, curtain coating or dip-coating, from a inorganic material particle suspension obtained in step (a);

 (d) drying said porous inorganic layer, preferably under a stream of air to obtain a porous inorganic layer;

(e) treating said porous inorganic layer by mechanical compression and / or heat treatment, (f) impregnating said porous inorganic layer obtained in step (e) with a phase carrying lithium ions.

Another subject of the invention is a method of manufacturing a thin-film electrolyte deposited on an electrode, said layer preferably being free of organic binder and preferably having a porosity, preferably mesoporous, greater than 30% by volume. , and even more preferably between 30% and 50% by volume, and said layer having pores with an average diameter D ₅ o less than 100 nm, preferably less than 80 nm, preferably less than 50 nm, said method being characterized in that

(a1) supplying a colloidal suspension comprising nanoparticles of at least one inorganic material P of average primary diameter D ₅ o less than or equal to 50 nm;

 (a2) the nanoparticles present in said colloidal suspension are destabilized so as to form aggregates or agglomerates of particles having a mean diameter of between 80 nm and 300 nm, preferably between 100 nm and 200 nm, said destabilization preferably being carried out by adding a destabilizing agent such as a salt, preferably LiOH;

 (b) supplying an electrode;

 (c) depositing on said electrode a porous inorganic layer by electrophoresis, by the process of ink jet printing, scraping, roll coating, curtain coating or dip-coating, from said suspension colloidal composition comprising aggregates or agglomerates of particles of at least one inorganic material obtained in step (a2);

 (d) drying the porous inorganic layer, preferably under a stream of air to obtain a porous inorganic layer;

 (e) treating said porous inorganic layer by mechanical compression and / or heat treatment,

 (f) impregnating said porous inorganic layer obtained in step (e) with a phase carrying lithium ions.

Advantageously, the porous inorganic layer obtained in step (c) has a thickness less than 10 μm, preferably less than 8 μm, and even more preferably between 1 μm and 6 μm. Advantageously, the porous inorganic layer obtained in step (d) has a thickness less than 10 μm, preferably between 3 μm and 6 μm, and preferably between 2.5 μm and 4.5 μm.

 Advantageously, the primary diameter of said nanoparticles is between 10 nm and 50 nm, preferably between 10 nm and 30 nm.

Preferably, the average pore diameter is between 2 nm and 50 nm, preferably between 6 nm and 30 nm and even more preferably between 8 nm and 20 nm.

The electrode is a dense electrode or a porous electrode, preferably a mesoporous electrode.

The method according to the invention can be used for the production of electrolytes in thin layers, in electronic, electrical or electrotechnical devices, and preferably in devices selected from the group formed by: batteries, capacitors, supercapacitors, capacitors, resistors, inductors, transistors, photovoltaic cells.

Another subject of the invention is a method for manufacturing a thin-film battery according to the invention, and comprising the steps of:

Supplying at least two conductive substrates, previously covered with a layer of a material that can serve as anode and respectively as cathode ("anode layer" 12 respectively "cathode layer" 22),

 Supplying a colloidal suspension comprising aggregates or agglomerates of nanoparticles of at least one inorganic material, said aggregates or said agglomerates having a mean diameter of between 80 nm and 300 nm (preferably between 100 nm and 200 nm) )

 Deposition of a porous inorganic layer by electrophoresis, by the process of ink jet printing, scraping, roll coating, curtain coating or dip-coating, from a suspension of aggregated particles of inorganic material obtained in step -2- on the cathode layer, respectively anode obtained in step -1 -,

Drying of the layer thus obtained in step -3-, preferably under a stream of air, -5- Stacking cathode and anode layers, preferably laterally shifted,

 Processing the stack of the anode and cathode layers obtained in step -5 by mechanical compression and / or heat treatment so as to juxtapose and assemble the porous inorganic layers present on the anode layers and cathode in order to obtain an all-solid rigid assembly, preferably free of organic binder, -7- Impregnation of the structure obtained in step -6- by a phase carrying lithium ions, preferably by a carrier phase of lithium ions comprising at least 50% by weight of at least one ionic liquid leading to obtaining an assembled stack, preferably a battery.

The order of steps -1 - and -2- does not matter.

 Advantageously, the cathode is a dense electrode or a porous electrode or, preferably, a mesoporous electrode. Advantageously, the anode is a dense electrode or a porous electrode or, preferably, a mesoporous electrode.

Advantageously, the dense electrode or the porous electrode or the mesoporous electrode is coated, preferably by an ALD atomic layer deposition method or by chemical deposition in CSD solution of the "Chemical Solution Deposition", of a layer an electronically insulating material, preferably an ionic conductor, preferably having a thickness of less than 5 nm. Advantageously, the cathode is a dense electrode or a dense electrode coated with ALD or CSD with an electronically insulating layer, preferably with an electronically insulating and ionically conductive layer, or a porous electrode or a porous electrode coated with ALD or with CSD of an electronically insulating layer, preferably an electronically insulating and ionically conductive layer or, preferably, a mesoporous electrode, or a mesoporous electrode coated by ALD or CSD with an electronically insulating layer, preferably a an electronically insulating and ionically conductive layer and / or wherein the anode is a dense electrode or a dense electrode coated by ALD or CSD with an electronically insulating layer, preferably an electronically insulating and ionically conductive layer, or an electrode porous or porous electrode coated with ALD or CSD with an electronically insulating layer, preferably an electronically insulating and ionically conductive layer or, preferably, a mesoporous electrode or a mesoporous electrode coated with ALD or CSD with an electronically insulating layer, preferably an electronically insulating and ionically conductive layer. Advantageously, when the cathode and / or the anode is a porous or mesoporous electrode, the impregnation of the structure (ie stack treated by mechanical compression and / or heat treatment) by a phase carrying lithium ions at the stage 7 allows impregnation of the porous inorganic layer and said cathode and / or said anode.

Advantageously, after the step -7-: one deposits successively, alternately, on the battery:

^■ at least a first layer of parylene and / or polyimide on said battery,

^■ at least a second layer composed of an electrically insulating material by ALD (Atomic Layer Deposition) on said first layer of parylene and / or polyimide,

^■ and the alternating succession of at least one first and at least a second layer is deposited a layer for protecting the battery against mechanical damage of the battery, preferably of silicone, epoxy resin or parylene, or polyimide forming, a system encapsulation of the battery,

 the battery thus encapsulated is cut off according to two section planes to expose each of the cutting planes of the anode and cathode connections of the battery, so that the encapsulation system covers four of the six faces of said battery, preferably continuously,

 we deposit successively, on and around, these anodic and cathodic connections:

^■ optionally, a first electronically conducting layer, preferably made of metal, preferably deposited by ALD,

^■ one second epoxy resin layer filled with silver, deposited on the first electronically conducting layer, and

^■ a third nickel-based layer deposited on the second layer, and

^■ a fourth layer based on tin or copper, deposited on the third layer. Advantageously and alternatively, after step -6-: alternatively, an assembly system formed by a succession of layers, namely a sequence, preferably of z sequences, is successively deposited on the assembled stack, comprising:

^■ a first cover layer, preferably selected from parylene, parylene F type, polyimide, epoxy, silicone, polyamide and / or a mixture thereof, deposited on the assembled stack,

^■ a second covering layer composed of an electrically insulating material deposited by atomic layer deposition on said first cladding layer,

^■ this sequence possibly being repeated once z with z> 1, depositing a final cap layer on this succession of layers of a material selected from epoxy resin, polyethylene naphthalate (PEN), polyimide, polyamide, polyurethane silicone, sol-gel silica or organic silica,

 cutting is carried out according to two cutting planes, the assembled stack thus encapsulated to expose on each of the cutting planes of the anode and cathode connections of the assembled stack, so that the encapsulation system covers four of the six faces of said stack assembled, preferably continuously, so as to obtain an elementary battery, and after step (7),

 - we deposit successively, on and around, these anodic and cathodic connections:

^■ a first layer of a material loaded with graphite, preferably epoxy resin loaded graphite,

^■ a second layer comprising copper metal obtained from an ink loaded in deposited copper nanoparticles on the first layer,

 the layers obtained are thermally treated, preferably by infrared flash lamp, so as to obtain a covering of the cathodic and anodic connections by a layer of metallic copper,

 optionally, this first stack of terminations is successively deposited on and around, a second stack comprising:

^■ a first layer of a tin-zinc alloy deposited, preferably by immersion in a tin-zinc molten bath to ensure the sealing of the battery at a lower cost, and ^■ a second layer of pure tin based deposited by electrodeposition or a second layer comprising a silver-based alloy, palladium, and copper deposited on this first layer of the second stack.

Advantageously, the anode and cathode connections 50 are on the opposite sides of the stack.

 Another subject of the invention relates to a battery, preferably a lithium ion battery, comprising at least one thin-film electrolyte according to the invention.

Another subject of the invention relates to a supercapacitor comprising at least one thin-film electrolyte according to the invention.

Brief description of the figures

 Figures 1 and 2 illustrate various aspects of embodiments of the invention, without limiting its scope.

 Figure 1 illustrates nanoparticles before (Figure 1 (a)) and after (Figure 1 (b)) heat treatment, illustrating the phenomenon of "necking".

 FIG. 2 (a) shows a diffractogram, FIG. 2 (b) a micrograph obtained by transmission electron microscopy of primary nanoparticles used for depositing the porous electrodes by electrophoresis.

 FIG. 3 is a diagrammatic view of a cutaway front view of a battery comprising an electrolyte according to the invention and showing the structure of the battery comprising an assembly of elementary cells covered by an encapsulation system and terminations.

List of references used in the figures:

 Table 1]

detailed description

 1. Definitions

For the purposes of this document, the size of a particle is defined by its largest dimension. By "nanoparticle" is meant any particle or object of nanometric size having at least one of its dimensions less than or equal to 100 nm.

In the context of the present document, an electronically insulating material or layer, preferably an electronically insulating and ionically conductive layer is a material or a layer whose electrical resistivity (resistance to electron passage) is greater than 10 ⁵ W-cm. By "ionic liquid" is meant any liquid salt capable of transporting electricity, differing from all the molten salts by a melting point of less than 100 ° C. Some of these salts remain liquid at room temperature and do not solidify even at very low temperatures. Such salts are called "ionic liquids at room temperature".

 By "mesoporous" materials is meant any solid which has within its structure pores called "mesopores" having a size intermediate between that of micropores (width less than 2 nm) and that of macropores (width greater than 50 nm), namely a size between 2 nm and 50 nm. This terminology corresponds to that adopted by IUPAC (International Union for Pure and Applied Chemistry), which refers to the skilled person. The term "nanopore" is therefore not used here, even if the mesopores as defined above have nanometric dimensions in the sense of the definition of the nanoparticles, knowing that the pores smaller than those of the mesopores are called by the skilled in the art of "micropores".

 A presentation of the concepts of porosity (and of the terminology just described above) is given in the article "Texture of pulverulent or porous materials" by F. Rouquerol et al. published in the collection "Techniques of the Engineer", treated Analysis and Characterization, fascicle P 1050; this article also describes the techniques for characterizing porosity, in particular the BET method.

For the purposes of the present invention, the term "mesoporous layer" means a layer which has mesopores. As will be explained below, in these layers, the mesopores contribute significantly to the total pore volume; this fact is translated by the expression "mesoporous layer of mesoporous porosity greater than X% by volume" used in the description below where X% is preferably greater than 25%, preferably greater than 30% and even more preferentially between 30 and 50% of the total volume of the layer. The term "aggregate" means, according to IUPAC definitions, a loosely bound assembly of primary particles. In this case, these primary particles are nanoparticles having a diameter that can be determined by transmission electron microscopy. Aggregate aggregated primary nanoparticles can normally be destroyed (ie reduced to primary nanoparticles) suspended in a liquid phase under the effect of ultrasound, according to a technique known to those skilled in the art.

 The term "agglomerate" means, according to IUPAC definitions, a strongly bound assembly of primary particles or aggregates.

For the purposes of the present invention, the term "electrolyte layer" refers to the layer within an electrochemical device, this device being capable of operating according to its purpose. By way of example, in the case where said electrochemical device is a battery secondary to lithium ions, the term "electrolyte layer" designates the "porous inorganic layer" impregnated with a phase carrying lithium ions.

 Said porous inorganic layer in an electrochemical device is here also called a "separator", according to the terminology used by those skilled in the art.

 According to the invention, the "porous inorganic layer", preferably mesoporous, can be deposited electrophoretically, by the dipping coating process hereinafter "dip-coating", by the ink-jet printing process. hereinafter "ink-jet", by roll coating (called "roll coating" in English), by curtain coating (called "curtain coating" in English) or by scraping hereinafter "doctor blade", and this to from a suspension of aggregates or agglomerates of nanoparticles, preferably from a concentrated suspension containing agglomerates of nanoparticles.

2. Preparation of suspensions

The deposition of polydisperse nanoparticles leads to the production of a porous structure having a closed porosity. Therefore, the use of these polydisperse nanoparticles is to be proscribed from the process according to the invention.

The process according to the invention uses electrophoresis, the ink-jet printing process, the scraping, the roll coating, the curtain coating or the dip-coating of nanoparticle suspensions as a technique for depositing coatings. porous layers, preferably mesoporous. In the context of the present invention it is preferable not to prepare these suspensions of nanoparticles from dry nanopowders. They can be prepared by grinding powders or nanopowders in the liquid phase. For example, particles may undergo wet nanomilling in ethanol; the particles may be ground with zirconia balls (for example with a diameter of 0.3 mm), for a few hours (for example 5 hours), until a primary particle size greater than or equal to 50 nm, preferably greater than 80 nm, more preferably between 50 nm and 150 nm; this avoids the uncontrolled sintering of the deposited layer, which could lead to the formation of dense layers. The conductivity of the suspension remains low, of the order of 20 μS / cm. One can thus obtain a size distribution which is unimodal, but which can be quite large. The disadvantage of nanomilling is the partial amorphization of the particle in an area close to the surface; this can hinder the treatment of deposited layers from these nanoparticles.

In another embodiment of the invention the nanoparticles are prepared in suspension directly by precipitation. The synthesis of nanoparticles by precipitation makes it possible to obtain primary nanoparticles of very homogeneous size with a unimodal size distribution i.e. very tight and monodisperse, good crystallinity and purity. The use of these nanoparticles of very homogeneous size and narrow distribution allows to obtain after deposition a porous structure of controlled and open porosity. The porous structure obtained after deposition of these nanoparticles has little, preferably does not have closed pores.

 In an even more preferred embodiment of the invention the nanoparticles are prepared directly at their primary size by solvothermal or hydrothermal synthesis; this technique makes it possible to obtain nanoparticles with a unimodal and very narrow size distribution; these particles are called here "monodisperse nanoparticles". Moreover, these particles have a very good crystallinity. The size of these non-aggregated or non-agglomerated particles is called their primary size. In the present invention it is preferably less than 100 nm, advantageously between 10 nm and 50 nm, preferably between 10 nm and 30 nm; this favors during the subsequent process steps the formation of a porous network, preferably mesoporous, interconnected, thanks to the phenomenon of "necking".

This suspension of monodisperse nanoparticles can be purified to remove any potentially troublesome ions present in the liquid phase. Depending on the degree of purification it can then be specially treated to form aggregates or agglomerates of a controlled size. More specifically, the formation of aggregates or agglomerates results from the destabilization of the suspension caused by ions. If the suspension has been completely purified it is stable, and ions are added for the destabilize, typically in the form of a salt; these ions are preferably lithium ions (added preferably in the form of LiOH).

 If the suspension has not been completely purified the formation of aggregates or agglomerates can be done alone spontaneously or by aging. This way of proceeding is simpler because it involves fewer purification steps, but it is more difficult to control the size of the aggregates or agglomerates. One of the essential aspects for the production of porous layers according to the invention consists in controlling the size of the primary particles used and their degree of aggregation or agglomeration.

It is this suspension of aggregates or agglomerates of nanoparticles which is then used to deposit by electrophoresis, by the process of inkjet printing, scraping, roll coating, curtain coating or dip coating. -coating the porous layers according to the invention. In one embodiment, the material used for the production of porous layers according to the invention is chosen from inorganic materials with low melting point, electronic insulators and stable in contact with the electrodes during the hot pressing steps. The more the materials will be refractory, the more it will be necessary to heat at the electrode / electrolyte interfaces, at high temperatures thus risking modifying the interfaces with the electrode materials, especially by interdiffusion, which generates parasitic reactions and creates problems. depletion layers whose electrochemical properties differ from those found in the same material at greater depth from the interface. Materials comprising lithium are preferred because they make it possible to avoid or even eliminate these phenomena of lium depletion.

The material used for the production of porous layers according to the invention is inorganic. In a particular embodiment, the material used for the manufacture of porous inorganic layers according to the invention is an electronically insulating material. It may, preferably, be chosen from GAI ₂ 0 ₃ , Si0 ₂ , Zr0 ₂ .

Alternatively, the material used for the manufacture of porous inorganic layers according to the invention may be an ionic conductive material such as a solid electrolyte comprising lithium in order to limit the modifications at the electrode / electrolyte interfaces.

 According to the invention, the solid electrolyte material used for the production of a porous inorganic layer may be chosen in particular from:

o garnets of formula Li _d A \ A ² _y (T0 ₄ ) z where ^■ A ¹ is a cation of oxidation + II, preferably Ca, Mg, Sr, Ba, Fe, Mn, Zn, Y, Gd; and or

^■ A ² represents a cation with an oxidation number + III, preferably Al, Fe, Cr, Ga, Ti, La; and or

^■ ₍₄ T0) represents an anion wherein T is an atom with an oxidation number + IV, located at the center of a tetrahedron formed by the oxygen atoms, and wherein T0 ₄ advantageously is the anion silicate or zirconate , knowing that all or part of the elements T of a degree of oxidation + IV can be replaced by atoms of a degree of oxidation + III or + V, such as Al, Fe, As, V, Nb, In , Ta;

^■ knowing that: d is between 2 and 10, preferably between 3 and 9, and even more preferably between 4 and 8; x is between 2.6 and 3.4 (preferably between 2.8 and 3.2); y is from 1.7 to 2.3 (preferably from 1.9 to 2.1) and z is from 2.9 to 3.1;

garnet, preferably selected from: Li ₇ La ₃ Zr20i2; Li ₆ La2BaTa ₂ 0i2; Li _5, 5La3Nbi, 75ln ₀ 25O12; Li ₅ La ₃ M ₂ 0i ₂ with M = Nb or Ta or a mixture of two compounds; Li _7-x Ba _{x 3-x} M ₂ O ₁₂ with 0 <x <1 and M = Nb or Ta or a mixture of the two compounds; Li _7-x La 3 Zr 2- _x M _x O 12 with 0 <x <2 and M = Al, Ga or Ta or a mixture of two or three of these compounds;

lithiated phosphates, preferably chosen from: lithiated phosphates of NaSICON type, U ₃ PO ₄ ; LiPO ₃ ; the U ₃ AIO, ₄ SCI, 6 (P0 ₄ ) 3 called "LASP"; the Lii, ₂ Zn, Ca _{9 0, i} (P0 _{4) 3;} LiZr ₂ (PO ₄ ) 3; Li 1 _{+ 3x} Zr 2 (Pi- _x Si _x O ₄ ) 3 with 1.8 <x <2.3; Li 1 _{+ 6x} Zr ₂ (Pi- _x B _x O ₄ ) 3 with 0 <x <0.25; Li3 (Sc _2-x M _x ) (PO ₄ ) 3 with M = Al or Y and O <x <1; Li 1 _{+ x} M _x (Sc) _{2- x} (PO ₄ ) 3 with M = Al, Y, Ga or a mixture of the three compounds and 0 <x <0.8; Ui _{+ x} Mx (Gai-yScy) ₂ -x (P0 ₄ ) 3 with 0 <x <0.8; 0 <y <1 and M = Al or Y or a mixture of the two compounds; Li 1 _{+ x} M _x (Ga) _{2- x} (PO ₄ ) 3 with M = Al, Y or a mixture of the two compounds and 0 <x <0.8; Li 1 _{+ x} Al _x Ti 2- _x (PO ₄ ) 3 with 0 <x <1 called "LATP"; or Lii _{+ x} AlxGe ₂ -x (P0 ₄ ) 3 with 0 <x <1 called "LAGP"; or Lii _{+ x + z} Mx (Gei-yTi _y ) 2-xSizP3-zOi2 with 0 <x <0.8 and 0 <y <1, 0 and 0 <z <0.6 and M = Al, Ga or Y or a mixture of two or three of these compounds; Li _{3 + y} (Sc 2- _x M _x ) QyP 3-y O 12 with M = Al and / or Y and Q = Si and / or Se, 0 <x <0.8 and 0 <y <1; or Li 1 _{+ x + y} M _x Sc 2- _x Q _y P 3- _y O ₂ with M = Al, Y, Ga or a mixture of the three compounds and Q = Si and / or Se, 0 <x <0.8 and 0 <y <1; or Li 1 _{+ x + y + z} M _x (Ga 1-yScy) 2-xQzP 3 -zO 2 with 0 <x <0.8, 0 £ y 1, 0 <z <0.6 with M = Al or Y or a mixing the two compounds and Q = Si and / or Se; or Li 1 _{+ x} Zr ₂ -xB _x (PO ₄ ) 3 with 0 <x <0.25; or Li 1 _{+ x} Zr ₂ -xCa _x (PO ₄ ) 3 with 0 <x <0.25; or ϋi _{+ c} M ³ _c M2-cR ₃ q _ΐ 2 with 0 <x <1 and M ³ = Cr, V, Ca, B, Mg, Bi and / or Mo, M = Sc, Sn, Zr, Hf, Se or If, or a mixture of these compounds; the lithiated borates, preferably chosen from: Li ₃ (Sc 2- _x M _x ) (B0 3) 3 with M = Al or Y and 0 <x <1; Li 1 _{+ x} M _x (Sc) 2 _x (B0 3) 3 with M = Al, Y, Ga or a mixture of the three compounds and 0 <x <0.8; Li 1 _{+ x} M _x (Ga 1- _y Sc _y ) 2 _x (B0 3) 3 with 0 <x <0.8, 0 <y <1 and M = Al or Y; Li 1 _{+ x} M _x (Ga) 2 _x (B0 3) 3 with M = Al, Y or a mixture of the two compounds and 0 <x <0.8; Li ₃ B0 _3, the U3BO3-U2SO4, Li _3-B03 Li2Si04 the U3BO3- Ü2Si0 ₄ -Li2S0 _4;

oxynitrides, preferably selected from U3PO4- _{X X} N2 _/ 3, Li ₄ Si04- _x N2 _{X /} 3, Li ₄ Ge0 ₄ - _x N _2x / 3 with 0 <x <4 or U3BO3- N2 _{X X} / 3 with 0 <x <3;

lithiated compounds based on lithium oxynitride and phosphorus, called "LiPON", in the form of Li _x PO _y N _z with x ~ 2.8 and 2y + 3z ~ 7.8 and 0.16 <z <0 , 4, and in particular U2,9PO _3, 3N _0, 46, but also the compounds Li _w PO _x N _y Sz with 2x + 3y + 2z = 5 = w or the compounds Li _w PO _x N _y S _z with 3.2 <x <3.8, 0.13 <y <0.4, 0 <z <0.2, 2.9 <w <3.3 or the compounds as Li _t P _x AlyO _u N _v S _w with 5x + 3y = 5, 2u + 3v + 2w = 5 + t, 2.9 <t <3.3, 0.84 <x <0.94, 0.094 <y <0.26, 3, 2 <u <3.8, 0.13 <v <0.46, 0 <w <0.2;

materials based on phosphorus or boron lithium oxynitrides, known as "LiPON" and "LIBON", respectively, which may also contain silicon, sulfur, zirconium, aluminum, or a combination of aluminum, boron , sulfur and / or silicon, and boron for phosphorus lithium oxynitride materials;

the lithiated compounds based on lithium oxynitride, phosphorus and silicon called "LiSiPON", and in particular Li1 9Si0 28P1OO1 1 N1 0;

lithium oxynitrides of LiBON, LiBSO, LiSiPON, LiSON, thio-LiSiCON, LiPONB (or B, P and S respectively represent boron, phosphorus and sulfur);

Lithium oxynitrides of LiBSO type such as (1-x) LiB0 ₂ -x Li ₂ S0 ₄ with 0.4 <x

<0.8;

the lithiated oxides, preferably chosen from U ₇ La ₃ Zr ₂ 0i ₂ or Li _{5 + x} La ₃ (Zr _x , A2- _x ) O 12 with A = Sc, Y, Al, Ga and 1.4 <x < 2 or L10, 35Lao, 55Ti0 ₃ or Li _3x La _2/3-x Ti0 ₃ with 0 <x <0.16 (LLTO);

silicates, preferably selected from U2S12O5, Li ₂ Si0 _3, U2S12O6, LiAISi0 ₄ U4S1O4, Li AIS12O6;

the solid electrolytes of anti-perovskite type chosen from: Li ₃ OA with a halide or a mixture of halides, preferably at least one of F, Cl, Br, I or a mixture of two or three or four of these elements; Li _(3-X) M _{X /} 20A with 0 <x <3, M a divalent metal, preferably at least one of Mg, Ca, Ba, Sr or a mixture of two or three or four of these elements, a halide or a mixture of halides, preferably at least one of F, Cl, Br, I or a mixture of two or three or four thereof; ϋ _(3-c) M ³ c _/ 30A with 0 <x <3, M ³ a trivalent metal, A halide or mixture of halides, preferably at least one element selected from F, mixture of two or three or four of these elements; or UCOX _z YY halides as mentioned above in connection with

the compounds Lao, 5i, 10, _34, 12, ₉₄ , Li _{4 4} Vo, 4G 2 O 5, LiAIGaSPO 4; the formulations based on U 2 CO 3, I (PO ₃ ) ₃ LiF, P ₂ S ₃ , Li ₂ S, Li ₃ N, Ui ₄ Zn (GeO 4) 4, Li ₃ , 6Geo, 6Vo, 404, LiTi 2 (P, 25Po , 25S4, L1, ₃ Alo, ₃ Tϊΐ, 7 (Rq4) _3> ϋ _{1 + c} AI _c M ₂ -c (R0 ₄ ) ₃ (where M = Ge, Ti, and / or x <1), Ui _{+ x + y} AlxTi2-xSiyP3-yOi2 (where 0 <x <1 and 0 <y <1).

For the production of battery assemblies the presence of a porous layer of solid electrolytes based on lithiated phosphates between the anodes and cathodes is preferred. These materials have relatively low melting points, and the particles weld relatively well at moderate temperatures. Moreover, the fact that they already contain inserted lithium prevents lithium from diffusing into the material during assembly, which could create areas of depletion on the surface.

 According to the findings of the applicant, with an average diameter of the aggregates or agglomerates of nanoparticles between 80 nm and 300 nm (preferably between 100 nm and 200 nm), during the subsequent process steps, a layer having a porosity is obtained. open, with an average pore diameter of less than 100 nm, preferably less than 80 nm, preferably between 2 nm and 80 nm, and even more preferably between 2 nm and 50 nm.

According to the invention, the porous inorganic layer can be deposited electrophoretically, by the process of ink jet printing, scraping, roll coating, curtain coating or dip-coating.

3. Deposition of a porous inorganic layer by electrophoresis

The process according to the invention can use the electrophoresis of nanoparticle suspensions as a technique for depositing the porous layers. The process of depositing layers from a suspension of nanoparticles is known per se (see, for example, EP 2 774 208 B1). The deposition by electrophoresis is done by the application of an electric field between the substrate on which the deposit is made, and a counter electrode, allowing to put the charged particles of the colloidal suspension in motion, and to deposit them on the substrate. To ensure the stability of the colloidal suspension, polar nanoparticles are preferably used, and / or the colloidal suspension advantageously has a Zeta potential in absolute value greater than 25 mV.

 The electrophoresis deposition is made from a suspension of particles of inorganic material suitable for use as a porous inorganic layer according to the invention, on a substrate having a sufficient electrical conductivity. Thus, it may be a metal substrate, for example a metal sheet (such as a stainless steel sheet with a thickness of about 5 μm), or a polymeric sheet or not metal having a conductive surface (for example coated with a layer of metal or a layer of a conductive oxide, such as a layer of ITO, which has the advantage of also acting as a diffusion barrier ). To manufacture a battery, the inorganic material can be electrophoretically deposited on a layer of electrode material (anode or cathode). Said layer of electrode material may have been deposited for example on a conductive substrate of metal foil type or polymer sheet coated with a conductive layer.

 In order for the electrophoresis to take place, a counter-electrode is placed in the suspension and a voltage is applied between the substrate and the counterelectrode.

 The electrophoretic deposition rate is a function of the applied electric field and the electrophoretic mobility of the particles of the suspension and can be very high. For an applied voltage of 200 V, the deposition rate can reach about 10 pm / min. The inventor has found that this technique makes it possible to deposit very homogeneous layers over very large areas (provided that the concentrations of particles and electric fields are homogeneous on the surface of the substrate). It lends itself as well to a continuous strip process, as in a batch process on plates.

The porous inorganic layer, preferably mesoporous, is deposited on an anode layer 12 and / or a cathode layer 22 themselves formed on a conductive substrate serving as a current collector by an appropriate method, and / or directly on a sufficiently conducting substrate serving as a current collector.

 This current collector substrate may be metallic, for example a metal sheet, or a metallized polymeric or non-metallic sheet (i.e. coated with a metal layer). The substrate is preferably selected from strips of titanium, copper, nickel or stainless steel.

The metal sheet may be coated with a layer of noble metal, in particular chosen from gold, platinum, palladium, titanium or alloys containing predominantly at least one or more of these metals, or a layer of material ITO type conductor (which has the advantage of also acting as a diffusion barrier). In batteries employing porous electrodes and porous inorganic layers according to the invention, the liquid phases carrying lithium ions which impregnate the pores are in direct contact with the current collector. However, when these liquid phases carrying lithium ions are in contact with the metal substrates and polarized at very anode potentials for the cathode and very cathodic for the anode, these liquid phases carrying lithium ions are susceptible to induce a dissolution of the current collector. These spurious reactions can degrade the life of the battery and accelerate its self-discharge. To avoid this, aluminum current collectors are used at the cathode, in all lithium ion batteries. Aluminum has the characteristic of being anodized with very anodic potentials, and the oxide layer thus formed on its surface protects it from dissolution. However, the aluminum has a melting temperature close to 60053 and can not be used for the manufacture of batteries comprising porous electrodes and an electrolyte according to the invention. The subsequent consolidation treatments of the porous electrodes and electrolytes according to the invention would lead to melting the current collector. Thus, to avoid spurious reactions that can degrade the life of the battery and accelerate its self-discharge, a titanium strip is advantageously used as a current collector at the cathode. During operation of the battery, the titanium strip will, like aluminum, anodize and its oxide layer will prevent any parasitic reactions dissolution of titanium in contact with the liquid electrolyte. In addition, since titanium has a much higher melting point than aluminum, fully solid electrodes according to the invention can be produced directly on this type of strip.

The use of these massive materials, in particular strips of titanium, copper or nickel, also protects the cutting edges of the battery electrodes corrosion phenomena. Stainless steel can also be used as a current collector, especially when it contains titanium or aluminum as an alloying element, or when it has a thin layer of protective oxide on the surface.

Other substrates serving as current collector may be used such as less noble metal strips coated with a protective coating, to avoid the possible dissolution of these strips induced by the presence of electrolytes on contact. These less noble metal strips may be copper strips, nickel or strip of metal alloys such as stainless steel strips, Fe-Ni alloy strips, Be-Ni-Cr alloy, alloy Ni-Cr or Ni-Ti alloy.

The coating that can be used to protect substrates serving as current collectors can be of different kinds. It can be a:

^■ thin layer obtained by sol-gel process of the same material as that of the electrode. The absence of porosity in this film makes it possible to avoid contact between the electrolyte and the metal current collector,

^■ thin layer obtained by vacuum deposition, particularly by physical vapor deposition (PVD or for English physical vapor deposition) or by chemical vapor deposition (CVD or for English Chemical vapor deposition), the same material as that of the electrode,

^■ Thin metal layer, dense, flawless, such as a thin layer of gold, titanium, platinum, palladium, tungsten or molybdenum. These metals can be used to protect current collectors because they have good conduction properties and can withstand heat treatments in the subsequent electrode manufacturing process. This layer can in particular be made by electrochemistry, PVD, CVD, evaporation, ALD,

^■ carbon thin film such as diamond-like carbon, graphic, deposited by ALD, PVD, CVD or by inking a sol-gel solution to obtain after heat treatment a inorganic layer doped with carbon to make it conductive, layer conductive oxides, such as a layer of ITO (indium-tin oxide) only deposited on the cathode substrate because the oxides are reduced to low potentials,

^■ layer of conductive nitrides such as TiN layer only deposited on the cathode substrate because nitrides insert the lithium at low potentials.

The coating that can be used to protect the substrates serving as current collectors must be electronically conductive so as not to interfere with the operation of the electrode subsequently deposited on this coating, making it too resistive.

In general, in order not to impact the operation of the battery cells too much, the maximum dissolution currents measured on the substrates, at the operating potentials of the electrodes, expressed in mA / cm ² , must be 1000 times lower than the surface capacities. electrodes expressed in pAh / cm ² . The porous inorganic layer, preferably mesoporous, is deposited on an anode layer 12 and / or a cathode layer 22. The deposition of a layer of material by electrophoresis allows a perfect overlap of the surface of the electrode layer whatever its geometry, the presence of roughness defects. It therefore makes it possible to guarantee the dielectric properties of the layer. In an advantageous embodiment, high frequency current pulses are applied because this avoids the formation of bubbles on the surface of the electrodes and the variations of the electric field in the suspension during the deposition. The thickness of the porous inorganic layer thus deposited is advantageously less than 10 μm, preferably less than 8 μm, and is even more preferably between 1 μm and 6 μm.

The compactness of the layer obtained by the electrophoretic deposition, and the absence of organic compounds in large quantities in the layer makes it possible to limit or even avoid the risk of cracks or appearance of other defects in the layer during the steps of drying. According to an essential characteristic of the present invention, the porous inorganic layer according to the invention does not comprise an organic binder.

4. Deposition of a porous inorganic layer by dip-coatina

Nanoparticles of an inorganic material can be deposited by the so-called "dip-coating" process, regardless of the chemical nature of the nanoparticles used. This deposition process is preferred when the inorganic nanoparticles are little or not electrically charged. In order to obtain a layer of a desired thickness, the dip-coating deposition step of the inorganic nanoparticles followed by the step of drying the layer obtained are repeated as much as necessary.

 Although this succession of dipping / drying coating steps is time-consuming, the dip-coating deposition process is a simple, safe, easy to implement, industrialize process; it makes it possible to obtain a homogeneous and compact final layer.

These nanoparticles are deposited on an anode layer 12 and / or a cathode layer 22 themselves formed on a conductive substrate serving as a current collector by an appropriate method, and / or directly on a sufficiently conducting substrate serving as a collector of as in previous section 3. 5. Treatment and properties of deposited layers

After they have been deposited, the layers must be dried; the drying must not induce the formation of cracks. For this reason it is preferred to perform it under conditions of controlled humidity and temperature.

 The dried layers can be consolidated by a pressing step and / or heat treatment. In a very advantageous embodiment of the invention, this mechanical (i.e. mechanical compression) and / or thermal treatment leads to a partial coalescence of the primary nanoparticles in the aggregates or agglomerates, and between adjacent aggregates or agglomerates; this phenomenon is called "necking" or "neck training". It is characterized by the partial coalescence of two particles in contact, which remain separated but connected by a neck (retreint); this is illustrated schematically in FIG. 1. Thus a three-dimensional network of interconnected particles is formed; this network has an open porosity formed by interconnected pores. The size of these pores is advantageously in the mesopore range, that is to say between 2 nm and 50 nm. Advantageously, the open pores of said porous inorganic layer have a volume greater than 25%, preferably greater than 30% of the total volume of said porous inorganic layer. When the pore volume of the porous inorganic layer is less than 25%, a three-dimensional network of interconnected particles can not be obtained; the layer obtained in this case has a closed porosity that does not allow the structure to be subsequently impregnated with a phase carrying lithium ions.

 The temperature required to obtain "necking" depends on the material; given the diffusive nature of the phenomenon that leads to necking, the duration of the treatment depends on the temperature.

 Depending on the case, this heat treatment, if it is carried out at a sufficient temperature, for example 350 53, also makes it possible to eliminate any organic residues resulting from the process for manufacturing the suspension of nanoparticles or solvents.

 The heat treatment and / or the pressing is advantageously carried out during subsequent manufacturing steps for other purposes; this is described in section 6 below in relation to the manufacture of batteries.

6. Assembling a battery

One of the aims of the invention is to provide new thin-layer electrolytes for batteries secondary to lithium ions. We describe here the production of a battery with an electrolyte comprising a porous inorganic layer. A suspension of nanoparticles of precursor material of a porous inorganic layer may be prepared by the solvothermal route, in particular the hydrothermal route, which leads directly to nanoparticles of good crystallinity. The porous inorganic layer is deposited by electrophoresis, by the ink-jet printing process, by scraping, by roll coating, by curtain coating or dip-coating on a cathode layer 22 covering a substrate 21 and / or on an anode layer 12 covering a substrate 11; in both cases said substrate 11, 21 must have sufficient conductivity to act as a cathode or anode current collector, respectively.

 The assembly of the cell formed by an anode layer, the porous inorganic layer and a cathode layer is carried out by hot pressing, preferably under an inert atmosphere. The temperature is advantageously between 300 ° C. and 500 ° C., preferably between 350 ° C. and 450 ° C. The pressure is advantageously between 40 MPa and 100 MPa. The hot pressing can be carried out for example at 350 ° C and 100 MPa.

Then, this cell, which is completely solid and rigid, and which contains no organic material, is impregnated by immersion in a phase carrying lithium ions. Because of the open porosity and the small size of the porosities (especially when the size D ₅ O of the pores is less than 50 nm), the impregnation in the whole of the cell (electrodes and separator) is done by capillarity. A particularly preferred separator is a Li ₃ Al _0, 4Sci _, 6 (PO 4) 3 separator having a mesoporosity. Details on the impregnation are given in section 7 below.

The carrier phase of lithium ions may contain, for example, LiPF ₆ or LiBF ₄ dissolved in an aprotic solvent, or an ionic liquid containing lithium salts. It is also possible to use ionic liquids, optionally dissolved in a suitable solvent, and / or mixed with organic electrolytes. For example, LiPF ₆ dissolved in EC / DMC can be mixed at 50% by mass with an ionic liquid containing lithium salts of LiTFSI type: PYR14TFSI (1: 9 molar ratio). It is also possible to produce mixtures of ionic liquids that can operate at low temperature, for example the LiTFSI: PYR13FSI: PYR14TFSI mixture (molar ratio 2: 9: 9).

EC is the current abbreviation for ethylene carbonate (CAS # 96-49-1). DMC is the current abbreviation for dimethyl carbonate (CAS No. 616-38-6). LITFSI is the current abbreviation for lithium bis-trifluoromethanesulfonimide (CAS RN: 90076-65-6). PYR13FSI is the current abbreviation of N-Propyl-N-methylpyrrolidinium bis (fluorosulfonyl) imide. PYR14TFSI is the current abbreviation for 1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide.

We describe here another example of manufacture of a lithium ion battery according to the invention. This process comprises the steps of:

 (1) supplying at least two conductive substrates previously covered with a layer of a material that can serve as anode and, respectively, as a cathode (these layers being called "anode layer" and "cathode layer"),

(2) Supply of a colloidal suspension consisting of aggregates or agglomerates of nanoparticles of at least one inorganic material, said aggregates or said agglomerates having an average diameter D ₅ o between 80 nm and 300 nm (preferably between 100 nm at 200 nm),

(3) Deposition of a porous inorganic layer by electrophoresis, by ink-jet printing, scraping, roll coating, curtain coating or dip-coating, from said colloidal suspension onto at least one cathode or anode layer obtained in step (1),

 (4) drying the layer thus obtained, preferably under a stream of air,

(5) Stacking cathode and anode layers, preferably laterally offset,

 (6) treatment of the stack of the anode and cathode layers obtained in step (5) by mechanical compression and / or heat treatment so as to juxtapose and assemble the porous inorganic layers present on the anode layers and cathode,

 (7) Impregnation of the structure obtained in step (6) with an electrolytic solution such as an ionic liquid comprising a lithium salt or a phase carrying lithium ions, preferably with a carrier phase of lithium ions comprising at least 50% by weight of at least one ionic liquid, to obtain a battery.

The order of steps (1) and (2) does not matter.

 The battery obtained is completely rigid, even when at least one ionic liquid is used, the latter being nanoconfigured in the pores of the porous layers.

The average primary diameter D ₅ o of the nanoparticles forming the aggregates or agglomerates of said suspension may be less than or equal to 50 nm, and in this case this suspension is preferably prepared by precipitation or by solvothermal synthesis. It may also be greater than 50 nm, preferably between 50 nm and 150 nm and in this case may be used suspensions obtained by wet grinding.

Advantageously, the anode and cathode layers may be dense electrodes, ie electrodes having a volume porosity of less than 20%, porous electrodes, preferably having an interconnected network of open pores or mesoporous electrodes, preferably having a interconnected network of open mesopores.

 Due to the very large specific surface area of the porous electrodes, preferably mesoporous, when used with a liquid electrolyte, parasitic reactions can occur between the electrodes and the electrolyte; these reactions are at least partially irreversible. In an advantageous embodiment, a very thin layer of an electronically insulating material, which is preferably an ionic conductor, is applied to the porous, preferably mesoporous, electrode layer in order to block these parasitic reactions.

 In the context of the dense electrodes and in another advantageous embodiment, a very thin layer of an electronically insulating material, which is preferably an ionic conductor, is applied to the electrode layer in order to reduce the interfacial resistance existing between the electrode and the electrode. dense electrode and electrolyte.

This layer of electronically insulating material, which is preferably an ionic conductor, advantageously has an electronic conductivity of less than 10 ^-8 S / cm. Advantageously, this deposit is made at least on one face of the electrode, whether it is porous or dense, which forms the interface between the electrode and the electrolyte. This layer may for example be alumina, silica, or zirconia. On the cathode we can use

Li ₄ Ti50i ₂ or another material which, like the LUTisO ^ _, has the characteristic of not inserting, at the operating voltages of the cathode, lithium and behaving as an electronic insulator.

Alternatively, this layer of an electronically insulating material may be an ionic conductor, which advantageously has an electronic conductivity of less than 10 ⁸ S / cm. This material must be chosen so as not to insert, at the operating voltages of the battery, lithium but only to transport it. It is possible to use, for example, U3PO4, U3BO3, lithium lanthanum zirconium oxide (called "LLZO"), such as Li ₇ La ₃ Zr ₂ 0i ₂ , which have a wide range of operating potential. In contrast, lithium lanthanum titanium oxide (abbreviated "LLTO"), such as Li _3x La _2/3-x TiO ₃ , lithium aluminum titanium phosphate (abbreviated "LATP"), lithium aluminum germanium phosphate (abbreviated "LAGP"), may be used only in contact with cathodes because their operating potential range is restricted; beyond this range they are likely to insert lithium in their crystallographic structure.

This deposit further improves the performance of lithium ion batteries comprising at least one electrode, whether porous or dense. In the case of impregnated porous electrodes, this deposit makes it possible to reduce the faradic reactions of interface with the electrolytes. These parasitic reactions are all the more important as the temperature is high; they cause reversible and / or irreversible losses of capacity. In the case of dense electrodes in contact with the electrolyte, it also makes it possible to limit the interface resistances related to the appearance of space charges.

Very advantageously this deposit is made by a technique allowing a coating coating (also called "compliant deposit"), i.e. a deposit that faithfully reproduces the atomic topography of the substrate on which it is applied. The technique of ALD (Atomic Layer Deposition) or CSD (Chemical Solution Deposition), known as such, may be suitable. It can be implemented on dense electrodes before deposition of the porous inorganic layer and before assembly of the cell. It can be implemented on the porous electrodes, preferably mesoporous after manufacture, before and / or after the deposition of the porous inorganic layer and before and / or after the assembly of the cell, preferably before the impregnation of the electrodes. porous by a phase carrying lithium ions.

 The ALD deposition technique is layer by layer, by a cyclic process, and allows a coating coating that faithfully reproduces the topography of the substrate; it covers the entire surface of the electrodes. This coating coating typically has a thickness between 1 nm and 5 nm. The CSD deposition technique makes it possible to produce a coating which faithfully reproduces the topography of the substrate; it covers the entire surface of the electrodes. This coating coating typically has a thickness less than 5 nm, preferably between 1 nm and 5 nm.

When the electrodes used are porous and covered with a nanolayer of an electronically insulating material, preferably an ionic conductor, it is preferable that the primary diameter D ₅ o of the particles of electrode material used to produce them is at least 10 nm to prevent the layer of the insulating material electronically, preferably ionic conductor, does not block the open porosity of the electrode layer.

The layer of an electronically insulating material, preferably an ionic conductor, must only be deposited on electrodes that do not contain an organic binder. Indeed the deposition by ALD is carried out at a temperature typically between 100 ° C and 300 53. At this temperature the organic materials forming the binder (for example the polymers contained in the electrodes made by ink casting tape) are likely to break down and will pollute the ALD reactor. On the other hand, the presence of residual polymers in contact with the electrode active material particles can prevent the ALD coating from coating all of the particle surfaces, which affects its effectiveness.

 By way of example, an alumina layer with a thickness of the order of 1.6 nm may be suitable.

If the electrode is a cathode it can be made from a cathode material P chosen from:

- the oxide LiMn ₂ 0 _4, Ui _{+ x} Mn _2-x O _4, with 0 <x <0.15, LiCo0 _2, LiNi0 _{2, Límni,} Nio _5, 50 _{4, Límni, 5 Nio,} 5 _x X _x Where X is selected from Al, Fe, Cr, Co, Rh, Nd, other rare earths such as Sc, Y, Lu, La, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er , Where Tm, Yb, and where 0 <x <0.1, LiMn _2-x M _x 0 ₄ with M = Er, Dy, Gd, Tb, Yb, Al, Y, Ni, Co, Ti, Sn, As, Mg or a mixture of these compounds and wherein 0 <x <0.4, LiFe0 ₂ , LiMni _{/ 3} Nii _{/ 3} Co _{/ 2,} LiNi0 8Co0 15AI0 05O2, LiAl _x Mn _2-x 0 ₄ with 0 <x <0 , 15, Linii _/ Coi _{x / y} Mni _{/ z} 0 ₂ with x + y + z = 10;

phosphates LiFePO ₄ , LiMnPO ₄ , LiCoPO ₄ , LiNiPO ₄ , Li ₃ V ₂ (PO ₄ ) ₃ ; phosphates of formula LiMM'PO ₄ , with M and M '(M ¹ M') selected from Fe, Mn, Ni, Co, V;

- all forms lithiated chalcogenide of the following: V ₂ 0 _5, V ₃ 0 _8, TiS _2, titanium oxysulfides (TiO _y S _z with z = 2-y, and 0.3 <y <1), the oxysulfides tungsten (WOySz with 0.6 <y <3 and 0.1 <z <2), CuS, CuS ₂ , preferably Li _x V ₂ 0 ₅ with 0 <x <2, ϋ _c n ₃ 0 ₈ with 0 <x <1, 7, Li _x TiS ₂ with 0 <x <1, the oxysulfides of titanium and lithium U _x TiOyS _z with z = 2-y, 0.3 <y <1, Li _x WO _y S _z , Li _x CuS, Li _x CuS ₂ . If the electrode is an anode it can be made from anode material P chosen from: carbon nanotubes, graphene, graphite;

lithium iron phosphate (of typical formula LiFePO ₄ );

mixed oxynitrides of silicon and tin (of the formula Si _a Sn _b Y _y N _z with a> 0, b> 0, a + b <2, 0 <y <4, 0 <z <3) (also called SiT ), and in particular SiSn _0.87 Oi, ₂ Ni, 7 ₂ ; as well as the oxynitride carbides of the formula Si _a Sn _b C _c OyN _z with a> 0, b> 0, a + b <2, 0 <c <10, 0 <y <24, 0 <z <17;

nitrites of type Si _x N _y (in particular with x = 3 and y = 4), Sn _x N _y (in particular with x = 3 and y = 4), Zn _x N _y (in particular with x = 3 and y = 2), Li _{3 -X} M _X N (with 0 <x <0.5 for M = Co, 0 <x <0.6 for M = Ni, 0 <x <0.3 for M = Cu) ; If _3-X M _X N ₄ with M = Co or Fe and 0 <x <3.

the oxides SnO ₂ , SnO, Li ₂ SnO ₃ , SnSiO ₃ , Li _x SiO _y (x> = 0 and 2>y> O), Li ₄ Ti ₅ O ₁₂ , TiNb ₂ O 7, Co ₃ O ₄ , SnB _{0 6} Po, ₄ 0 _{2, g} and Ti0 _2,

the composite oxides TiNb ₂ 0 ₇ comprising between 0% and 10% by mass of carbon, preferably the carbon being chosen from graphene and carbon nanotubes.

On dense, porous, preferably mesoporous electrodes, coated or not with a layer of an electronically insulating material, preferably an ionic conductor by ALD or by chemical solution, known under the acronym CSD ("Chemical" Solution Deposition "), an electrolyte according to the invention can be produced.

In order to obtain a high energy density and high power density battery, this battery advantageously contains a porous, preferably mesoporous layer of anode and a cathode layer, and an electrolyte according to the invention.

Advantageously, the layers of anodes and cathodes, coated or not with an ALD layer of an electronically insulating material, preferably an ionic conductor, and then covered with a porous inorganic layer are hot-pressed to promote the assembly of the cell without inducing sintering. The deposits remain porous and can be subsequently impregnated with an electrolytic solution, avoiding any risk of a subsequent short circuit.

Advantageously, a battery comprising at least one porous electrode, preferably mesoporous and an electrolyte according to the invention has increased performance, including a high power density. We describe below an example of manufacture of a lithium ion battery according to the invention comprising at least one porous electrode, preferably mesoporous. This process comprises the steps of:

(1) supplying a colloidal suspension comprising nanoparticles of at least one cathode material of average primary diameter D ₅ o less than or equal to 50 nm;

(2) providing a colloidal suspension comprising nanoparticles of at least one anode material of average primary diameter D ₅ o less than or equal to 50 nm;

 (3) Providing at least two flat conductive substrates, preferably metallic, said conductive substrates being able to serve as current collectors of the battery,

 (4) Deposition of at least one thin layer of cathode, respectively anode, preferably by dip-coating, by the process of ink jet printing, scraping, roll coating, curtain coating or by electrophoresis, preferably by galvanostatic electrodeposition by pulsed currents, from said suspension of nanoparticles of material obtained in step (1), respectively in step (2), on said substrate obtained in step (3) ,

 (5) drying the layer thus obtained in step (4),

 (6) Optionally, ALD deposition of a layer of an electronically insulating material on the surface of the cathode layer, and / or anode obtained in step (5),

 (7) Electrophoretic deposition, ink jet printing, scraping, roll coating, curtain coating or dip coating of a porous inorganic layer from a colloidal suspension comprising aggregates or agglomerates of nanoparticles of at least one inorganic material, on the cathode layer, and / or anode obtained in step 5) or step 6), to obtain a first and / or an second intermediate structure,

 (8) drying the layer thus obtained in step (7), preferably under a stream of air,

 (9) Realization of a stack from said first and / or second intermediate structure to obtain a "substrate / anode / porous inorganic layer / cathode / substrate" type stack:

Or by depositing an anode layer on said first intermediate structure, Or by depositing a cathode layer on said second intermediate structure,

 Or by superimposing said first intermediate structure and said second intermediate structure so that the two layers of porous inorganic layers are laid one on the other,

 (10) Hot pressing of the stack obtained in step (9),

 (1 1) Impregnation of the structure obtained in step (10) or step (1 1) by a lithium ion carrier phase leading to obtaining an impregnated structure, preferably a cell.

The order of steps (1), (2) and (3) does not matter.

 Advantageously, said aggregates or agglomerates of nanoparticles of at least one inorganic material have a mean diameter of between 80 nm and 300 nm, preferably between 100 nm and 200 nm.

Once the assembly of a stack constituting a battery by hot pressing is complete, it can be impregnated with a phase carrying lithium ions. This phase may be a solution formed by a lithium salt dissolved in an organic solvent or a mixture of organic solvents, and / or dissolved in a polymer containing at least one lithium salt, and / or dissolved in an ionic liquid (ie a molten lithium salt) containing at least one lithium salt. This phase can also be a solution formed from a mixture of these components. The porous electrodes, preferably mesoporous, are capable of absorbing a liquid phase by simple capillarity when the average diameter D ₅ o of the pores is between 2 nm and 80 nm, preferably between 2 nm and 50 nm, preferably between 6 nm and 30 nm, preferably between 8 nm and 20 nm. This effect is quite unexpected and is particularly favored with the decrease of the pore diameter of these electrodes.

 Advantageously, the pores of the porous electrode, preferably mesoporous, are impregnated with an electrolyte, preferably a phase carrying lithium ions such as an ionic liquid containing lithium salts, possibly diluted in an organic solvent or a mixture of organic solvents containing a lithium salt which may be different from that dissolved in the ionic liquid.

A lithium ion battery cell of very high power density is thus obtained. 7. Impregnation of porous inorganic layers

As indicated in the preceding section, once the deposition of a porous inorganic layer and its treatment, for example during the assembly of a stack constituting a battery by hot pressing, completed, it can be impregnated with a phase carrying lithium ions. This phase may be a solution formed by a lithium salt dissolved in an organic solvent or a mixture of organic solvents, and / or dissolved in a polymer containing at least one lithium salt, and / or dissolved in an ionic liquid (ie a molten lithium salt) containing at least one lithium salt. This phase can also be a solution formed from a mixture of these components.

The inventors have found that the porous inorganic layers according to the invention are capable of absorbing a liquid phase by simple capillarity. This quite unexpected effect is specific to porous inorganic layer deposits according to the invention; it is particularly favored when the average diameter D ₅ o of the mesopores is between 2 nm and 80 nm, preferably between 2 nm and 50 nm, preferably between 6 nm and 30 nm, and even more preferably between 8 nm and 20 nm.

In an advantageous embodiment of the invention, the porous inorganic layer has a porosity and preferably a mesoporous porosity, greater than 30%, the average pore diameter D ₅ o less than 50 nm, and a primary particle diameter less than 30 nm. Its thickness is advantageously less than 10 μm, preferably between 3 μm and 6 μm, and preferably between 2.5 μm and 4.5 μm, so as to reduce the final thickness of the battery without reducing its properties. It is free of binder. Its pores are impregnated with an electrolytic solution, such as an ionic liquid containing lithium salts, possibly diluted in an organic solvent or a mixture of organic solvents containing a lithium salt which may be different from that dissolved in the ionic liquid.

 In a particularly advantageous embodiment the porosity, preferably mesoporous, is between 35% and 50%, and even more preferably between 40% and 50%.

The "nanoconfined" or "nanopiégé" liquid in the porosities, and in particular in the mesoporosities, can no longer stand out. It is linked by a phenomenon called here "absorption in the mesoporous structure" (which does not seem to have been described in the literature in the context of lithium ion batteries) and it can not go out even when the cell is evacuated . The battery is then considered almost solid.

The carrier phase of lithium ions may be an ionic liquid containing lithium salts, possibly diluted with an organic solvent or with a mixture of solvents organic compounds containing a lithium salt which may be different from that dissolved in the ionic liquid.

 The ionic liquid consists of a cation associated with an anion; this anion and this cation are chosen so that the ionic liquid is in the liquid state in the operating temperature range of the accumulator. The ionic liquid has the advantage of having high thermal stability, reduced flammability, nonvolatility, low toxicity and good wettability of ceramics, which are materials that can be used as electrode materials. Surprisingly, the mass percentage of ionic liquid contained in the lithium ion carrier phase may be greater than 50%, preferably greater than 60% and even more preferably greater than 70%, and this in contrast to lithium ion batteries. lithium of the prior art where the mass percentage of ionic liquid in the electrolyte must be less than 50% by mass so that the battery retains a high capacity and a high voltage discharge and a good stability in cycling. Above 50% by mass the capacity of the battery of the prior art is degraded, as indicated in the application US 2010/209 783 A1. This can be explained by the presence of polymeric binders within the electrolyte of the battery of the prior art; these binders are weakly wetted by the ionic liquid inducing poor ionic conduction within the carrier phase of lithium ions thus causing degradation of the capacity of the battery.

 Batteries using a porous electrode according to the invention are preferably free of binder. As a result, these batteries can employ a phase carrying lithium ions comprising more than 50% by mass of at least one ionic liquid without degrading the final capacity of the battery.

 The carrier phase of lithium ions may comprise a mixture of several ionic liquids.

Advantageously, the ionic liquid may be a type 1-ethyl-3-methylimidazolium cation (also called EMI +) and / or n-propyl-n-methylpyrrolidinium (also called PYRi3 ⁺ ) and / or n-butyl-n- methylpyrrolidinium (also called PYR _I4 ⁺ ), associated with bis (trifluoromethanesulfonyl) imide (TFSL) and / or bis (fluorosulfonyl) imide (FSI) anions. To form an electrolyte, a lithium salt such as LiTFSI may be dissolved in the ionic liquid which serves as a solvent or in a solvent such as γ-butyrolactone. Γ-Butyrolactone prevents the crystallization of ionic liquids inducing a greater temperature operating range of the latter, especially at low temperatures.

The carrier phase of lithium ions may be an electrolytic solution comprising PYR14TFSI and LiTFSI; these abbreviations will be defined below. Advantageously, when the porous anode or cathode comprises a lithiated phosphate surface protective film, the lithium ion carrier phase may comprise a solid electrolyte such as LiBH ₄ or a mixture of LiBH ₄ with one or more selected compounds. among LiCl, Lil and LiBr. LiBH ₄ is a good conductor of lithium and has a low melting point facilitating its impregnation in porous electrodes, especially by soaking. Due to its extremely reducing properties, LiBH ₄ is not widely used as an electrolyte. The use of a protective film on the surface of the porous lithiated phosphate electrodes prevents the reduction of the electrode materials, in particular cathode materials, by the LiBH ₄ and avoids the degradation of the electrodes.

Advantageously, the carrier phase of lithium ions comprises at least one ionic liquid, preferably at least one ionic liquid at ambient temperature, such as PYR14TFSI, optionally diluted in at least one solvent, such as γ-butyrolactone.

Advantageously, the carrier phase of lithium ions comprises between 10% and 40% by weight of a solvent, preferably between 30 and 40% by weight of a solvent, and even more preferably between 30 and 40% by weight of y-butyrolactone. .

 Advantageously, the carrier phase of lithium ions comprises more than 50% by weight of at least one ionic liquid and less than 50% of solvent, which limits the risks of safety and ignition in the event of malfunction of the batteries comprising such carrier phase of lithium ions.

 Advantageously, the carrier phase of lithium ions comprises:

 between 30 and 40% by weight of a solvent, preferably between 30 and 40% by weight of g-butyrolactone, and

 more than 50% by weight of at least one ionic liquid, preferably more than 50% by mass of PYR14TFSI.

The carrier phase of lithium ions may be an electrolytic solution comprising PYR14TFSI, LiTFSI and g-butyrolactone, preferably an electrolytic solution comprising approximately 90% by weight of PYR14TFSI, 0.7 M of LiTFSI and 10% by mass of y-butyrolactone.

8. Encapsulation

The battery 1 or the assembly, a rigid multilayer system consisting of one or more assembled cells, optionally impregnated with a phase carrying lithium ions, must then be encapsulated by a suitable method to ensure its protection vis-à-vis of the atmosphere. The encapsulation system comprises at least one layer, and preferably represents a stack of several layers. If the encapsulation system is composed of a single layer, it must be deposited by ALD or be in parylene and / or polyimide. These encapsulation layers must be chemically stable, withstand high temperatures and be impermeable to the atmosphere (barrier layer). One of the methods described in patent applications WO 2017/1 15 032, WO 2016/001584, WO2016 / 001588 or WO 2014/131997 can be used. Advantageously, the battery or the assembly may be covered with an encapsulation system formed by a stack of several layers, namely a sequence, preferably z sequences, comprising:

 a first covering layer, preferably chosen from parylene, type F parylene, polyimide, epoxy resins, silicone, polyamide and / or a mixture thereof, deposited on the stack of sheets of anode and cathode,

 a second covering layer composed of an electrically insulating material deposited by depositing atomic layers on said first covering layer.

 This sequence can be repeated z times with z> 1. This multilayer sequence has a barrier effect. The more the sequence of the encapsulation system will be repeated, the more this barrier effect will be important. It will be all the more important that the thin films deposited will be numerous.

 Advantageously, the first covering layer is a polymeric layer, for example silicone (deposited for example by impregnation or plasma-enhanced chemical vapor deposition from hexamethyldisiloxane (HMDSO)), or epoxy resin, or polyimide , polyamide, or poly-para-xylylene (better known as parylene), preferably based on parylene and / or polyimide. This first covering layer makes it possible to protect the sensitive elements of the battery of its environment. The thickness of said first cover layer is preferably between 0.5 μm and 3 μm.

Advantageously, the first covering layer may be parylene type C, parylene type D, parylene type N (CAS 1633-22-3), type F parylene or a mixture of parylene type C, D , N and / or F. Parylene (also known as polyparaxylylene or poly (p-xylylene)) is a dielectric, transparent, semi-crystalline material which exhibits high thermodynamic stability, excellent solvent resistance and very low permeability. Parylene also has barrier properties to protect the battery from its external environment. The protection of the battery is increased when this first covering layer is made from parylene type F. It can be deposited under vacuum, by a technique of chemical vapor deposition (CVD). This first encapsulation layer is advantageously obtained from the condensation of gaseous monomers deposited by chemical vapor deposition (CVD) on the surfaces, which makes it possible to have a conformal, thin and uniform covering of all the surfaces. accessible from the object. It makes it possible to follow the variations of volume of the battery during its operation and facilitates the clean cutting of the batteries due to its elastic properties. The thickness of this first encapsulation layer is between 2 μm and 10 μm, preferably between 2 μm and 5 μm and even more preferably around 3 μm. It makes it possible to cover all the accessible surfaces of the stack, to close only on the surface access to the pores of these accessible surfaces and to standardize the chemical nature of the substrate. The first cover layer does not enter the pores of the battery or the assembly, the size of the deposited polymers being too large for them to enter the pores of the stack.

 This first covering layer is advantageously rigid; it can not be considered a soft surface. The encapsulation can thus be carried out directly on the stacks, the coating being able to penetrate all the available cavities.

 It is recalled here that due to the absence of binder in the porosities of the electrolyte according to the invention and / or electrodes, the battery can undergo vacuum treatments.

 In one embodiment, a first layer of parylene, such as a layer of parylene C, of parylene D, a layer of parylene N (CAS No. 1633-22-3) or a layer comprising a mixture of parylene is deposited. C, D and / or N. Parylene (also known as polyparaxylylene or poly (p-xylylene)) is a dielectric, transparent, semi-crystalline material with high thermodynamic stability, excellent solvent resistance and very low permeability. .

 This parylene layer protects the sensitive elements of the battery from their environment. This protection is increased when this first encapsulation layer is made from N. parylene.

 In another embodiment, a first polyimide layer is deposited. This layer of polyimide protects the sensitive elements of the battery of their environment.

In another advantageous embodiment, the first encapsulation layer consists of a first layer of polyimide, preferably about 1 μm thick on which is deposited a second layer of parylene, preferably about 2 pm thick. This protection is increased when this second layer of parylene, Preferably about 2 μm thick is made from parylene N. The polyimide layer associated with the parylene layer improves the protection of the sensitive elements of the battery of their environment.

 However, the inventors have observed that this first layer, when it is based on parylene, does not have sufficient stability in the presence of oxygen. When this first layer is based on polyimide, it does not have a sufficient seal, especially in the presence of water. For these reasons, a second layer is deposited which coats the first layer.

 Advantageously, a second covering layer composed of an electrically insulating material may be deposited by a conformal deposition technique, such as the deposition of atomic layers (ALD) on the first layer. Thus, a conformal covering of all the accessible surfaces of the stack previously coated with the first covering layer, preferably of a first layer of parylene and / or polyimide, is obtained; this second layer is preferably an inorganic layer. The growth of the layer deposited by ALD is influenced by the nature of the substrate. A layer deposited by ALD on a substrate having different zones of different chemical natures will have an inhomogeneous growth, which can cause a loss of integrity of this second protective layer. This second layer deposited on the first layer of parylene and / or polyimide protects the first layer of parylene and / or polyimide against the air and improves the life of the encapsulated battery.

ALD deposition techniques are particularly well suited to cover surfaces with a high roughness in a completely sealed and compliant manner. They make it possible to produce conformal layers, free of defects, such as holes (so-called "pinhole free" layers) and represent very good barriers. Their WVTR coefficient is extremely low. The WVTR coefficient (water vapor transmission rate) is used to evaluate the water vapor permeance of the encapsulation system. The lower the WVTR coefficient, the more the encapsulation system is watertight. By way of example, an Al ₂ O ₃ layer of 100 nm thick deposited by ALD exhibits a water vapor permeation of 0.00034 g / m ² d. The second covering layer may be ceramic material, vitreous material or glass-ceramic material, for example in the form of oxide, Al ₂ 0 _{3 type} , nitride, phosphates, oxynitride, or siloxane. This second covering layer has a thickness of less than 200 nm, preferably between 5 nm and 200 nm, more preferably between 10 nm and 100 nm, between 10 nm and 50 nm, and even more preferably of the order of about fifty nanometers. This second covering layer deposited by ALD makes it possible, on the one hand, to seal the structure, ie to prevent the migration of water inside the structure and, on the other hand, to protect the first one. covering layer, preferably of parylene and / or polyimide, preferably of type F parylene, of the atmosphere in order to avoid its degradation.

 However, these layers deposited by ALD are very mechanically fragile and require a rigid bearing surface to ensure their protective role. The deposition of a brittle layer on a flexible surface would lead to the formation of cracks, causing a loss of integrity of this protective layer.

In one embodiment, a third covering layer is deposited on the second covering layer or on an encapsulation system formed by a stack of several layers as described above, namely a sequence, preferably z sequences. encapsulation system with z> 1, to increase the protection of the battery cells of their external environment. Typically, this third layer is made of polymer, for example silicone (deposited for example by impregnation or plasma-enhanced chemical vapor deposition from hexamethyldisiloxane (HMDSO, CAS No. 107-46-0)), or epoxy resin, or parylene, or polyimide.

In addition, the encapsulation system may comprise an alternating succession of layers of parylene and / or polyimide, preferably about 3 μm thick, and layers composed of an electrically insulating material such as inorganic layers deposited conformally by ALD as previously described to create a multi-layer encapsulation system. In order to improve the encapsulation performance, the encapsulation system may advantageously comprise a first layer of parylene and / or polyimide, preferably about 3 μm thick, a second layer composed of an electrically isolator, preferably an inorganic layer, ALD-conformally deposited on the first layer, a third layer of parylene and / or polyimide, preferably about 3 μm thick deposited on the second layer and a fourth layer composed of of an electrically insulating material conformably deposited by ALD on the third layer.

The battery or assembly thus encapsulated in this sequence of the encapsulation system, preferably in z sequences, can then be coated with a final covering layer so as to mechanically protect the thus encapsulated stack and possibly give an aesthetic appearance. This last layer of cover protects and improves the life of the battery. Advantageously, this last covering layer is also chosen to withstand a high temperature, and has sufficient mechanical strength to protect the battery during its subsequent use. Advantageously, the thickness of this last covering layer is between 1 μm and 50 μm. Ideally, the thickness of this last cover layer is about 10-15 pm, such a range of thickness can protect the battery against mechanical damage.

Advantageously, this last covering layer is deposited on an encapsulation system formed by a stack of several layers as described above, namely a sequence, preferably z sequences of the encapsulation system with z> 1, preferably on this alternating succession of layers of parylene and / or polyimide, preferably about 3 μm thick and inorganic layers deposited in a conformal manner by ALD, to increase the protection of the battery cells of their external environment and to protect them against mechanical damage. This last encapsulation layer preferably has a thickness of about 10-15 μm. This last covering layer is preferably based on epoxy resin, polyethylene naphthalate (PEN), polyimide, polyamide, polyurethane, silicone, sol-gel silica or organic silica. Advantageously, this last covering layer is deposited by dipping. Typically, this last layer is made of polymer, for example silicone (deposited for example by dipping or plasma-enhanced chemical vapor deposition from hexamethyldisiloxane (HMDSO)), or epoxy resin, or parylene, or polyimide. For example, an injection of a silicone layer (typical thickness about 15 μm) can be deposited to protect the battery against mechanical damage. These materials withstand high temperatures and the battery can thus be easily assembled by soldering on electronic cards without the appearance of a glass transition. Advantageously, encapsulation of the battery is performed on four of the six faces of the stack. The encapsulation layers surround the periphery of the stack, the rest of the protection against the atmosphere being provided by the layers obtained by the terminations.

After the encapsulation step, the thus encapsulated stack is then cut according to section planes making it possible to obtain unitary battery components, with the exposure on each of the section planes of the anode and cathode connections 50 of the battery, so that the encapsulation system 30 covers four of the six faces of said battery, preferably continuously, so that the system can be assembled without welding, the other two faces of the battery being subsequently coated by the terminations 40.

 In an advantageous embodiment, the stack thus encapsulated and cut, can be impregnated, under anhydrous atmosphere, with a phase carrying lithium ions such as an ionic liquid containing lithium salts, possibly diluted in an organic solvent. or a mixture of organic solvents containing a lithium salt which may be different from that dissolved in the ionic liquid, as presented in paragraph 10 of the present application. The impregnation may be carried out by dipping in an electrolytic solution such as an ionic liquid containing lithium salts, possibly diluted in an organic solvent or a mixture of organic solvents containing a lithium salt that may be different from that dissolved in the liquid. ionic. The ionic liquid returns instantly by capillarity in the porosities.

After the step of encapsulation, cutting and possibly impregnation of the battery, terminations 40 are added to establish the electrical contacts necessary for the proper functioning of the battery.

9. Termination

Advantageously, the battery comprises terminations 40 at the level where the cathodic current collectors, respectively anodic, are apparent. Preferably, the anode connections and the cathode connections are on the opposite sides of the stack. On and around these connections 50 is deposited a termination system 40. The connections can be metallized using plasma deposition techniques known to those skilled in the art, preferably by ALD and / or immersion in an epoxy resin conductive (charged with silver) and / or a molten tin bath. Preferably, the terminations consist of a stack of layers successively comprising a first thin layer of electronically conductive coating, preferably metallic, deposited by ALD, a second layer of silver-filled epoxy resin deposited on the first layer and a third layer. based on tin deposited on the second layer. The first conductive layer deposited by ALD serves to protect the battery section from moisture. This first conductive layer deposited by ALD is optional. It increases the battery life of the battery by reducing the WVTR at the termination. This first thin covering layer may in particular be metallic or based on metal nitride. The second epoxy resin layer loaded with silver allows to provide "flexibility" to the connection without breaking the electrical contact when the electric circuit is subjected to thermal and / or vibratory stresses.

 The third layer of tin metallization serves to ensure the solderability of the battery.

 In another embodiment, this third layer may be composed of two layers of different materials. A first layer coming into contact with the epoxy resin layer loaded with silver. This layer is made of nickel and is made by electrolytic deposition. The nickel layer serves as a thermal barrier and protects the remainder of the diffusion component during the reflow assembly steps. The last layer, deposited on the nickel layer is also a metallization layer, preferably tin to make the compatible interface assemblies by reflow. This layer of tin can be deposited either by dipping in a bath of molten tin or by electrodeposition; these techniques are known as such.

 For some assemblies on copper copper lanes, it may be necessary to have a final layer of copper metallization. Such a layer can be made by electrodeposition instead of tin.

 In another embodiment, the terminations 40 may consist of a stack of layers successively comprising a layer of silver-filled epoxy resin and a second layer based on tin or nickel deposited on the first layer.

 In another embodiment, the terminations 40 may consist of a stack of layers successively comprising a silver-filled epoxy resin layer, a second nickel-based layer deposited on the first layer and a third layer based on tin or copper.

 In another preferred embodiment, the terminations 40 consist, in the vicinity of the cathode and anode connections, of a first stack of layers successively comprising a first layer of a graphite-loaded material, preferably a graphite filled epoxy resin. and a second layer comprising metallic copper obtained from an ink charged with copper nanoparticles deposited on the first layer. This first stack of terminations is then sintered by infra-red flash lamp so as to obtain a covering of the cathodic and anodic connections by a layer of metallic copper.

Depending on the end use of the battery, the terminations may additionally comprise a second stack of layers disposed on the first stack of terminations successively comprising a first layer of deposited tin-zinc alloy, preferably by dipping. in a bath of molten tin-zinc, in order to ensure the sealing of the battery at a lower cost and a second layer based on electrodeposited pure tin or a second layer comprising an alloy based on silver, palladium and copper deposited on this first layer of second stack.

 The terminations 40 make it possible to resume the alternately positive and negative electrical connections on each end of the battery. These terminations 40 make it possible to make the electrical connections in parallel between the different battery elements. For this, only the cathode connections 50 exit on one end, and the anode connections 50 are available on another end.

 In another preferred embodiment, a lithium ion battery according to the invention is manufactured by the method comprising the following steps:

(1) supplying a colloidal suspension comprising aggregates or agglomerates of nanoparticles of at least one inorganic material, said aggregates or agglomerates having a mean diameter of between 80 nm and 300 nm (preferably between 100 nm and 200 nm),

 (2) supplying at least one electrode,

 (3) depositing on at least said electrode a porous inorganic layer by electrophoresis, by the process of ink jet printing, scraping, roll coating, curtain coating or dip-coating, from a suspension of particles of inorganic material obtained in step (1);

 (4) drying said porous inorganic layer, preferably under a stream of air to obtain a porous inorganic layer;

 (5) treating said porous inorganic layer by mechanical compression and / or heat treatment,

 (6) optionally, said porous inorganic layer obtained in step (5) is impregnated with a phase carrying lithium ions.

 (7) there is provided a stack comprising an alternating succession of cathode and anode layers in thin layers, preferably laterally offset, so that at least one porous inorganic layer is disposed between a cathode layer and a layer anode

 (8) consolidating the stack by mechanical compression and / or heat treatment in order to obtain an assembled stack,

(9) optionally, the assembled stack obtained in step (8) comprising said porous inorganic layer is impregnated with a phase carrying lithium ions. After step (9) of the method for manufacturing a lithium ion battery according to the invention:

alternatively, an assembly system formed by a succession of layers, namely a sequence, preferably of z sequences, is successively deposited alternately on the assembled stack, comprising:

^■ a first cover layer, preferably selected from parylene, parylene F type, polyimide, epoxy, silicone, polyamide and / or a mixture thereof, deposited on the assembled stack,

^■ a second covering layer composed of an electrically insulating material deposited by atomic layer deposition on said first cladding layer,

^■ this sequence possibly being repeated once z with z> 1,

 a final covering layer is deposited on this succession of layers of a material chosen from epoxy resin, polyethylene naphthalate (PEN), polyimide, polyamide, polyurethane, silicone, sol-gel silica or silica; organic,

 the assembled stack thus encapsulated is cut off according to two cutting planes so as to expose each of the cutting planes of the anode and cathode connections of the assembled stack, so that the encapsulation system covers four of the six faces of said stack assembled, preferably in a continuous manner, so as to obtain an elementary battery,

 optionally, the elementary battery encapsulated and cut by a phase carrying lithium ions is impregnated,

 - we deposit successively, on and around, these anodic and cathodic connections:

^■ a first layer of a material loaded with graphite, preferably epoxy resin loaded graphite,

^■ a second layer comprising copper metal obtained from an ink loaded in deposited copper nanoparticles on the first layer,

 the layers obtained are thermally treated, preferably by infrared flash lamp, so as to obtain a covering of the cathodic and anodic connections by a layer of metallic copper,

optionally, this first stack of terminations is successively deposited on and around, a second stack comprising: ^■ a first layer of a tin-zinc alloy deposited, preferably by immersion in a tin-zinc molten bath to ensure the sealing of the battery at a lower cost, and

^■ a second layer of pure tin based deposited by electrodeposition or a second layer comprising a silver-based alloy, palladium, and copper deposited on this first layer of the second stack.

In this process, the deposition of a layer of an electronically insulating material, preferably an ionic conductor, by ALD or by chemical solution deposition CSD of the "Chemical Solution Deposition" may be carried out after treatment of the porous inorganic layer with mechanical compression and / or heat treatment, after consolidation of the stack by mechanical compression and / or heat treatment to obtain an assembled stack or after cutting into two cutting planes, the stack assembled to expose on each cutting planes the anode and cathode connections of the assembled stack. This deposition of a layer of an electronically insulating material, preferably an ionic conductor, is advantageously carried out before any step of impregnating the porous inorganic layer with a phase carrying lithium ions. This deposit preferably has a thickness of less than 5 nm.

In this process, the impregnation of the porous inorganic layer with a phase carrying lithium ions can be carried out after treatment of the porous inorganic layer by mechanical compression and / or heat treatment, after consolidation of the stack by mechanical compression and / or heat treatment for obtaining an assembled stack or after cutting according to two section planes, the assembled stack for exposing on each of the section planes the anode and cathode connections of the assembled stack. In another preferred embodiment, a lithium ion battery according to the invention is manufactured by the same method as that indicated above, except for step 1) which comprises the following steps:

(1 a) supplies a colloidal suspension comprising nanoparticles of at least one inorganic material P of average primary diameter D ₅ o less than or equal to 50 nm;

(1b) the nanoparticles present in said colloidal suspension are destabilized so as to form aggregates or agglomerates of particles with a mean diameter of between 80 nm and 300 nm, preferably between 100 nm and 200 nm, said destabilization being preferably by adding a destabilizing agent such as a salt, preferably LiOH.

Advantageously, the anode and cathode connections are on the opposite sides of the stack. All embodiments relating to the assembly of the battery, the impregnation of the porous inorganic layer, the deposition of the encapsulation system and the terminations described above can be combined independently of each other, moment that this combination is realistic for the skilled person.

Examples

EXAMPLE 1 Production of a Mesoporous Electrolyte Layer Based on Li ₃ PO ₄ Filtered on a Cathode Layer a. Production of a suspension of nanoparticles of U ₃ P0 ₄

Two solutions have been prepared:

1 1, 44 g of CH ₃ COOLi, 2H ₂ 0 were dissolved in 12 ml of water, then 56 ml of water were added with vigorous stirring to the medium in order to obtain a solution A.

4.0584 g of H ₃ PO was diluted in 105.6 ml of water, then 45.6 ml of ethanol was added to this solution in order to obtain a second solution, hereinafter referred to as solution B.

Solution B was then added, with vigorous stirring, to solution A.

 The solution obtained, perfectly clear after the disappearance of the bubbles formed during mixing, was added to 1.2 liters of acetone under the action of a homogenizer type Ultraturrax ™ to homogenize the medium. White precipitation was immediately observed in suspension in the liquid phase.

The reaction medium was homogenized for 5 minutes and then kept for 10 minutes with magnetic stirring. It was allowed to settle for 1 to 2 hours. The supernatant was discarded and the remaining suspension was centrifuged for 10 minutes at 6000 rpm. Then 300 ml of water were added to return the precipitate in suspension (use of a sonotrode, magnetic stirring). Under vigorous stirring, 125 ml of a solution of sodium tripolyphosphate at 10Og / l was added to the colloidal suspension thus obtained. The suspension has thus become more stable. The suspension was then sonicated to using a sonotrode. The suspension was then centrifuged for 15 minutes at 8000 rpm. The pellet was then redispersed in 150 ml of water. Then the suspension obtained was again centrifuged for 15 minutes at 8000 rpm and the pellets obtained redispersed in 300 ml of ethanol in order to obtain a suspension capable of producing electrophoretic deposition.

Agglomerates of about 100 nm consisting of primary particles of Li ₃ PO of 10 nm were thus obtained in suspension in ethanol. b. Production of a porous inorganic layer according to the invention based on a suspension of nanoparticles of U ₃ PO ₄ i. Realization of a mesoporous cathode based on UC0O2

A suspension of crystalline nanoparticles of UC0O2 was prepared by hydrothermal synthesis. For 100 ml of suspension, the reaction mixture was carried out by adding 20 ml of a 0.5M aqueous solution of cobalt nitrate hexahydrate added with stirring in 20 ml of a 3M solution of lithium hydroxide monohydrate followed a dropwise addition of 20 ml of 50% H ₂ 0 ₂ . The reaction mixture was placed in an autoclave at 200 ° C for 1 hour; the pressure in the autoclave reached about 15 bars.

A black precipitate was obtained in suspension in the solvent. This precipitate was subjected to a succession of centrifugation - redispersion steps in water, until a suspension with a conductivity of about 200 pS / cm 2 and a zeta potential of -30 mV was obtained. The size of the primary particles was of the order of 10 nm to 20 nm and the aggregates had a size between 100 nm and 200 nm. The product has been characterized by X-ray diffraction and electron microscopy.

These aggregates were electrophoretically deposited on stainless steel strips of a thickness of 5 μm in an aqueous medium, applying pulse currents of 0.6 A peak and 0.2 A average; the applied voltage was of the order of 4 to 6 V for 400 s. There was thus obtained a deposit of about 4 microns thick. It was consolidated at 60053 for 1 hour in the air in order to weld the nanoparticles together, to improve adhesion to the substrate and to perfect the recrystallization of UC0O2. ii. Realization of a mesoporous anode based on Li ₄ Ti ₅ 0i ₂

A suspension of Li ₄ Ti ₂ O ₁₂ nanoparticles was prepared by glycothermal synthesis: 190 ml of 1,4-butanediol was poured into a beaker, and 4.25 g of lithium acetate was added with stirring. The solution was stirred until acetate is dissolved complement. 16.9 g of titanium butoxide were taken under an inert atmosphere and introduced into the acetate solution. The solution was then stirred for a few minutes before being transferred to an autoclave previously filled with an additional 60 ml of butanediol. The autoclave was then closed and purged with nitrogen for at least 10 minutes. The autoclave was then heated to 300 at 535 / min and held at this temperature for 2 hours with stirring. At the end, it was allowed to cool, still stirring.

 A white precipitate was obtained in suspension in the solvent. This precipitate was subjected to a succession of centrifugation - redispersion steps in ethanol to obtain a pure colloidal suspension with a low ionic conductivity. It consisted of aggregates of about 150 nm consisting of primary particles of 10 nm. The zeta potential was of the order of -45 mV. The product has been characterized by X-ray diffraction and electron microscopy. Figure 2 (a) shows a diffractogram, Figure 2 (b) a picture obtained by transmission electron microscopy of primary particles.

These aggregates were electrophoretically deposited on stainless steel strips of a thickness of 5 μm in an aqueous medium, applying pulse currents of 0.6 A peak and 0.2 A average; the applied voltage was of the order of 3 to 5 V for 500 s. There was thus obtained a deposit of about 4 microns thick. It was consolidated by RTA annealing at 40% power for 1 s under nitrogen in order to weld the nanoparticles together, to improve adhesion to the substrate and to perfect the recrystallization of LpTisO · ^ · iii. Realization on previously developed anode and cathode layers of a porous inorganic layer from the suspension of U3PO4 nanoparticles previously described in part a)

 Porous thin layers of U3PO4 were then electrophoretically deposited on the surface of the anode and cathode previously prepared by applying an electric field of 20V / cm to the previously obtained U3PO4 nanoparticle suspension, for 90 seconds to obtain a layer of thickness of about 1.5 μm. This layer was air dried at 12053 to remove any traces of organic residues, and then calcined at 35053 for one hour in air.

Example 2: Production of an Electrochemical Cell

After having deposited 1.5 μm of porous U ₃ PO ₄ on each of the electrodes (UC0O 2 and U ₄ Ti ₅ O ₁₂ ) previously produced, the two subsystems were stacked Li ₃ P0 ₄ films are in contact. This stack was then hot pressed under vacuum.

To do this, the stack was placed under a pressure of 1.5 MPa and then dried under vacuum for 30 minutes at 10 ^-3 bar. The platens of the press were then heated to 450 ° C with a speed of 4 ^q C / seconds. At 450 ° C., the stack was then heat-compressed under a pressure of 45 MPa for 1 minute, after which the system was cooled to room temperature.

 Once assembled, a rigid multilayer system consisting of one or more assembled battery cells was obtained.

This assembly was then impregnated in an electrolytic solution comprising PYR14TFSI and 0.7M LiTFSI. The ionic liquid returned instantly by capillarity in the pores. The system was kept immersed for 1 minute, then the surface of the cell stack was dried by an N ₂ slide.

Claims

1. Thin-film electrolyte (13, 23) in an electrochemical device such as a lithium-ion battery, said electrolyte comprising a porous inorganic layer impregnated with a phase carrying lithium ions,  characterized in that said porous inorganic layer has an interconnected network of open pores. 2. Thin film electrolyte (13, 23) according to claim 1, characterized in that the open pores of said porous inorganic layer have an average diameter D ₅ o less than 100 nm, preferably less than 80 nm, preferably between 2 nm and 80 nm, and even more preferably between 2 nm and 50 nm, and a volume greater than 25% of the total volume of said thin-layer electrolyte, and preferably greater than 30%. Thin film electrolyte (13, 23) according to Claim 1 or Claim 2, characterized in that the open pores of said porous inorganic layer have a volume of between 30% and 50% of the total volume of said thin-film electrolyte. . 4. Thin film electrolyte (13, 23) according to any one of claims 1 to 3, characterized in that said porous inorganic layer is free of organic binder. 5. Thin film electrolyte (13, 23) according to any one of claims 1 to 4, characterized in that its thickness is less than 10 μm, preferably between 3 μm and 6 μm, and preferably between 2, 5 pm and 4, 5 pm. Thin film electrolyte (13, 23) according to any one of claims 1 to 5, characterized in that said porous inorganic layer comprises an electronically insulating material, preferably selected from AI ₂ 0 ₃ , SiO ₂ , Zr0 ₂ , and / or a material selected from the group consisting of: o garnets of formula Li _d A ¹ _x A ² _y (T0 ₄ ) z where A ¹ represents a cation of degree of oxidation + II, preferably Ca, Mg, Sr, Ba, Fe, Mn, Zn, Y, Gd; and or ^■ A ² represents a cation of degree of oxidation 111, preferably Al, Fe, Cr, Ga, Ti, La; and or ^■ ₍₄ T0) represents an anion wherein T is an atom with an oxidation number + IV, located at the center of a tetrahedron formed by the oxygen atoms, and wherein T0 ₄ advantageously is the anion silicate or zirconate , knowing that all or part of the elements T of a degree of oxidation + IV can be replaced by atoms of a degree of oxidation +111 or + V, such as Al, Fe, As, V, Nb, In , Ta; ^■ knowing that: d is between 2 and 10, preferably between 3 and 9, and even more preferably between 4 and 8; x is between 2.6 and 3.4 (preferably between 2.8 and 3.2); y is from 1.7 to 2.3 (preferably from 1.9 to 2.1) and z is from 2.9 to 3.1; garnet, preferably selected from: Li ₇ La ₃ Zr20i2; Li ₆ La2BaTa20i2; Li _5, 5La3Nbi, 75ln ₀ 25O12; LisLasI LO ^ with M = Nb or Ta or a mixture of the two compounds; Li _7-x Ba _{x 3-x} M ₂ O ₁₂ with 0 <x <1 and M = Nb or Ta or a mixture of the two compounds; U _7-x La 3 Zr 2- _x M _x O 12 with 0 <x <2 and M = Al, Ga or Ta or a mixture of two or three of these compounds; lithiated phosphates, preferably chosen from: lithiated phosphates of NaSICON type, Li ₃ PO ₄ ; LiPO ₃ ; Li ₃ AI _0.4 Sci, 6 (PO ₄ ) 3 called "LASP"; the Lii, ₂ Zn, Ca _{9 0, i} (P0 _{4) 3;} LiZr ₂ (PO ₄ ) 3; Li 1 _{+ 3x} Zr ₂ (Pi- _x Si _x O ₄ ) 3 with 1.8 <x <2.3; Li 1 _{+ 6x} Zr ₂ (Pi- _x B _x O ₄ ) 3 with 0 <x <0.25; Li3 (Sc _2-x M _x ) (PO ₄ ) 3 with M = Al or Y and O <x <1; U _{I + X} M _X (SC) ₂ -X (PO ₄ ) ₃ with M = Al, Y, Ga or a mixture of the three compounds and 0 <x <0.8; U 1 _{+ x} M x (Ga 1-y S y) 2-x (PO ₄ ) 3 with 0 <x 0.8; 0 £ y <1 and M = Al or Y or a mixture of the two compounds; Li 1 _{+ x} M _x (Ga) _2-x (PO ₄ ) ₃ with M = Al, Y or a mixture of the two compounds and 0 <x <0.8; the Li _{1 + x} Al _x Ti2- _X (P0 _{4) 3} with 0 <x <1 called "PAL"; or Lii _{+ x} AlxGe ₂ -x (P0 ₄ ) 3 with 0 <x <1 called "LAGP"; or Lii _{+ x + z} Mx (Gei-yTi _y ) 2-xSizP3-zOi2 with 0 <x <0.8 and 0 <y <1, 0 and 0 <z <0.6 and M = Al, Ga or Y or a mixture of two or three of these compounds; Li _{3 + y} (Sc 2- _x M _x ) QyP 3-y O 12 with M = Al and / or Y and Q = Si and / or Se, 0 <x <0.8 and 0 <y <1; or Ui _{+ x + y} M _x Sc2- _x Q _y P3- _y O12 with M = Al, Y, Ga or a mixture of the three compounds and Q = Si and / or Se, 0 <x <0.8 and 0 <y <1; or the Ui _{+ x + y + z} Mx (Gai-yScy) ₂ -xQzP3-zOi ₂ with 0 <x <0.8, 0 <y <1, 0 <z <0.6 with M = Al or Y or a mixture of the two compounds and Q = Si and / or Se; or Li _{1 + x} Zr _{2 c} B _c (R0 ₄ ) ₃ with 0 <x <0.25; or Li 1 _{+ x} Zr ₂ -xCa _x (PO ₄ ) 3 with 0 <x <0.25; or U _{I + X} M ³ _X M2- _X P30 _I 2 with 0 <x <1 and M ³ = Cr, V, Ca, B, Mg, Bi and / or Mo, M = Sc, Sn, Zr, Hf, Se or Si, or a mixture of these compounds; the lithiated borates, preferably chosen from: Li ₃ (Sc 2-xMx) (B0 3) 3 with M = Al or Y and O <x <1; Li 1 _{+ x} M _x (Sc) 2 _x (B0 3) 3 with M = Al, Y, Ga or a mixture of three compounds and 0 <x <0.8; the Lii _{+ x} Mx (vering _y Sc _y) 2-x (B03) 3 with 0 <x <0.8, 0 <y <1 and M = Al or Y; Li 1 _{+ x} M _x (Ga) 2 _x (B0 3) 3 with M = Al, Y or a mixture of the two compounds and 0 <x <0.8; the ϋ ₃ B0 _3, the U3BO3-U2SO4 the LhBOs-L ^ SiO Li _{3-B03-Li2Si04} Li2S04! oxynitrides, preferably selected from R04-ϋ ₃ cN _{2c /} 3, Li ₄ Si04- N2X _x / 3, Li ₄ Ge04- N2X _x / 3 with 0 <x <4 u or _{c 3} B03- N _2c / 3 with 0 <x <3; lithiated compounds based on lithium oxynitride and phosphorus, called "LiPON", in the form of Li _x PO _y N _z with x ~ 2.8 and 2y + 3z ~ 7.8 and 0.16 <z <0 , 4, and in particular Li _2.9 P0 _3.3 No _{, 46} , but also the compounds Li _w PO _x N _y S _z with 2x + 3y + 2z = 5 = w or the compounds Li _w PO _x N _y S _z with 3.2 <x <3.8, 0.13 <y <0.4, 0 <z <0.2, 2.9 <w <3.3 or compounds in the form of Li _t PxAl _y OrNvSw with 5x + 3y = 5, 2u + 3v + 2w = 5 + t, 2.9 <t <3.3, 0.84 <x <0.94, 0.094 <y <0.26, 3.2 <u <3.8, 0.13 <v <0.46, 0 <w <0.2; materials based on phosphorus or boron lithium oxynitrides, known as "LiPON" and "LIBON", respectively, which may also contain silicon, sulfur, zirconium, aluminum, or a combination of aluminum, boron , sulfur and / or silicon, and boron for phosphorus lithium oxynitride materials; the lithiated compounds based on lithium oxynitride, phosphorus and silicon called "LiSiPON", and in particular Li1 9Si0 28P1OO1 1 N1 0; lithium oxynitrides of LiBON, LiBSO, LiSiPON, LiSON, thio-LiSiCON, LiPONB (or B, P and S respectively represent boron, phosphorus and sulfur); lithium oxynitrides type LiBSO such as (1 -x) LiB0 ₂ - xLi ₂ S0 ₄ with 0.4 <x <0.8; the lithiated oxides, preferably chosen from U ₇ La ₃ Zr ₂ O 12 or Li _{5 + x} La 3 (Zr _x , A2-x) O 12 with A = Sc, Y, Al, Ga and 1.4 <x <2 or Lio, 35Lao, 55Ti0 ₃ or Li _3x La2 _/ 3- _x TiO3 with 0 <x <0.16 (LLTO); the silicates, preferably chosen from Li ₂ Si ₂ O 5, Li ₂ SiO ₃ , Li ₂ Si ₂ O 6, LiAISiO ₄ , U ₄ SiO ₄ , LiAlSiO; the solid electrolytes of anti-perovskite type chosen from: Li ₃ OA with a halide or a mixture of halides, preferably at least one of F, Cl, Br, I or a mixture of two or three or four of these elements; U _(3-X) M _{X /} 20A with 0 <x <3, M a divalent metal, preferably at least one of Mg, Ca, Ba, Sr or a mixture of two or three or four of these elements, a halide or a mixture of halides, preferably at least one of F, Cl, Br, I or a mixture of two or three or four of these elements; ϋ _{(3 -c)} c M ³ _/ 30A with 0 <x <3, M ³ a trivalent metal, A halide or a mixture of halides, preferably at least one of F, a mixture of two or three or four of these elements; or LICOX and Y halides as mentioned above in relation av <1, where the compounds Lao, 5i I- io, Ti2 _{34, 94,} Li ₃ Vo _4, 4Geo ₆ 04 U20 NB20-4! the formulations based on U ₂ CO 3, B ₂ O ₃ , Li ₂ O, Al (PO _{3 2} S, Li ₃ N, Li ₄ Zn (GeO 4) 4, Li _{3 6} Geo, ₆ Vo, 404, LiTi 2 (PO 4 ) ₃ , ,, 25 '', 25S4, ϋi, ₃ IOA, ₃ TIi, ₇ (R 0 _{4) 3,} ϋi _{+ c} AIcM2-c (R 0 _{4) 3} (where M = Ge, Ti and / or Hf, and where 0 <x <1), Li 1 _{+ x + y} Al _x Ti 2- _x SiyP 3- _y O 12 (where 0 <x <1 and 0 <y <1). Thin film electrolyte (13, 23) according to any one of claims 1 to 6, characterized in that said pores are impregnated with a phase carrying lithium ions, such as an organic solvent or a mixture of solvents in which at least one lithium salt is dissolved, and / or a polymer containing at least one lithium salt, and / or an ionic liquid or a mixture of ionic liquids, possibly diluted with a suitable solvent, containing at least one less a lithium salt. Thin film electrolyte (13, 23) according to any one of Claims 1 to 6, characterized in that the said pores are impregnated with a phase carrying lithium ions comprising at least 50% by weight of at least one ionic liquid. 9. A method of manufacturing a thin-film electrolyte (13, 23) deposited on an electrode (12, 22), said layer preferably being free from organic binder and preferably having a porosity, preferably mesoporous, greater than 30. % by volume, and even more preferably between 30% and 50% by volume, and said layer having pores of average diameter D ₅ o less than 100 nm, preferably less than 80 nm and preferably less than 50 nm, said method characterized in that:  (a) supplying a colloidal suspension comprising aggregates or agglomerates of nanoparticles of at least one inorganic material, said aggregates or agglomerates having a mean diameter of between 80 nm and 300 nm (preferably between 100 nm and 200 nm),  (b) supplying an electrode (12, 22), (c) depositing on said electrode a porous inorganic layer by electrophoresis, by the ink jet printing process, by scraping, by roll coating, curtain coating or dip-coating, from a suspension of particles of inorganic material obtained in step (a);  (d) drying said porous inorganic layer, preferably under a stream of air to obtain a porous inorganic layer;  (e) treating said porous inorganic layer by mechanical compression and / or heat treatment,  (f) impregnating said porous inorganic layer obtained in step (e) with a phase carrying lithium ions. 10. A method of manufacturing a thin-film electrolyte (13, 23) deposited on an electrode, said layer preferably being free of organic binder and preferably having a porosity, preferably mesoporous, greater than 30% by volume, and more preferably between 30% and 50% by volume, and said layer having pores with an average diameter D ₅₀ less than 100 nm, preferably less than 80 nm, preferably less than 50 nm, said method being characterized in that: (a1) supplying a colloidal suspension comprising nanoparticles of at least one inorganic material P of average primary diameter D ₅ o less than or equal to 50 nm;  (a2) the nanoparticles present in said colloidal suspension are destabilized so as to form aggregates or agglomerates of particles having a mean diameter of between 80 nm and 300 nm, preferably between 100 nm and 200 nm, said destabilization preferably being carried out by adding a destabilizing agent such as a salt, preferably LiOH;  (b) supplying an electrode;  (c) depositing on said electrode a porous inorganic layer by electrophoresis, by the process of ink jet printing, scraping, roll coating, curtain coating or dip-coating, from said suspension colloidal composition comprising aggregates or agglomerates of particles of at least one inorganic material obtained in step (a2); (d) drying the porous inorganic layer, preferably under a stream of air to obtain a porous inorganic layer; (e) treating said porous inorganic layer by mechanical compression and / or heat treatment,  (f) impregnating said porous inorganic layer obtained in step (e) with a phase carrying lithium ions. The process according to claim 9 or 10, wherein the porous inorganic layer obtained in step (c) has a thickness of less than 10 μm, preferably less than 8 μm, and even more preferably between 1 μm and 6 μm. pm. 12. Process according to any one of claims 9 to 11, in which the porous inorganic layer obtained in step (d) has a thickness of less than 10 μm, preferably of between 3 μm and 6 μm, and preferentially comprised between between 2.5 pm and 4.5 pm. 13. The method according to any one of claims 9 to 12, wherein the primary diameter of said nanoparticles is between 10 nm and 50 nm, preferably between 10 nm and 30 nm. 14. A method according to any one of claims 9 to 13, wherein the average pore diameter is between 2 nm and 50 nm, preferably between 6 nm and 30 nm and even more preferably between 8 nm and 20 nm. The method of any one of claims 9 to 14, wherein the electrode is a dense electrode or a porous electrode, preferably a mesoporous electrode. 16. Use of a method according to any one of claims 9 to 15 for the manufacture of electrolytes in thin film, in electronic, electrical or electrotechnical devices, and preferably in devices selected from the group consisting of: batteries, capacitors, supercapacitors, capacitors, resistors, inductors, transistors. 17. A method of manufacturing a thin-film battery, implementing the method according to one of claims 9 to 15 and comprising the steps of: Supplying at least two conductive substrates (1 1, 21), previously covered with a layer of a material that can be used as anode and respectively as cathode ("anode layer" respectively "cathode layer"),  Supplying a colloidal suspension comprising aggregates or agglomerates of nanoparticles of at least one inorganic material, said aggregates or said agglomerates having a mean diameter of between 80 nm and 300 nm (preferably between 100 nm and 200 nm) )  Deposition of a Porous Inorganic Layer by Electrophoresis, Ink-jet Printing, Scraping, Roll Coating, Curtain Coating or Dip Coating from a Particle Suspension aggregates of inorganic material obtained in step -2- on the cathode layer, respectively anode obtained in step -1 -,  Drying of the layer thus obtained in step -3-, preferably under a stream of air,  -5- Stacking cathode and anode layers, preferably laterally shifted,  Processing the stack of the anode and cathode layers obtained in step -5 by mechanical compression and / or heat treatment so as to juxtapose and assemble the porous inorganic layers present on the anode layers and cathode,  Impregnation of the structure obtained in step -6- by a phase carrying lithium ions, preferably by a phase carrying lithium ions comprising at least 50% by weight of at least one ionic liquid leading to obtaining an assembled stack, preferably a battery. 18. The method of claim 17, wherein the cathode is a dense electrode or a dense electrode coated with ALD an electronically insulating layer, preferably an electronically insulating layer and ionic conductive, or a porous electrode, or an electrode porous material coated with ALD with an electronically insulating layer, preferably an electronically insulating and ionically conductive layer, or, preferably, a mesoporous electrode, or a mesoporous electrode coated with ALD with an electronically insulating layer, preferably with an electronically insulating and ionic conductive layer, and / or wherein the anode is a dense electrode, or a ALD-coated dense electrode of an electronically insulating layer, preferably an electronically insulating and ionically conductive layer, or a porous electrode, or an ALD-coated porous electrode of an electronically insulating layer, preferably an insulating layer electronically and ionically conductive, or preferably a mesoporous electrode, or a mesoporous electrode coated with ALD an electronically insulating layer, preferably an electronically insulating layer and ionic conductive. The method of any one of claims 17 to 18, wherein after step -7-: - is deposited successively, alternately, on the battery:  At least a first layer of parylene and / or polyimide on said battery, ^■ at least a second layer composed of an electrically insulating material by ALD (Atomic Layer Deposition) on said first layer of parylene and / or polyimide,  And on the alternating succession of at least a first and at least a second layer is deposited a layer for protecting the battery against mechanical damage to the battery, preferably silicone, epoxy resin or parylene, or polyimide forming, a system encapsulation of the battery, the battery thus encapsulated is cut out according to two cutting planes so as to expose each of the cutting planes of the anode and cathode connections of the battery, so that the encapsulation system covers four of the six faces of said battery, preferably continuously,  we deposit successively, on and around, these anodic and cathodic connections: ^■ optionally, a first electronically conducting layer, preferably made of metal, preferably deposited by ALD, ^■ one second epoxy resin layer filled with silver, deposited on the first electronically conducting layer, and ^■ a third nickel-based layer deposited on the second layer, and ^■ a fourth layer based on tin or copper, deposited on the third layer. The method of claim 17, wherein after step -6-: alternatingly, on the assembled stack, an encapsulation system (30) formed by a succession of layers, namely a sequence, preferably of z sequences, is successively deposited, comprising: ^■ a first cover layer, preferably selected from parylene, parylene F type, polyimide, epoxy, silicone, polyamide and / or a mixture thereof, deposited on the assembled stack, ^■ a second covering layer composed of an electrically insulating material deposited by atomic layer deposition on said first cladding layer, ^■ this sequence possibly being repeated once z with z> 1, a final covering layer is deposited on this succession of layers of a material chosen from epoxy resin, polyethylene naphthalate (PEN), polyimide, polyamide, polyurethane, silicone, sol-gel silica or silica; organic, the assembled stack thus encapsulated is cut off according to two cutting planes so as to expose each of the cutting planes of the anode and cathode connections of the assembled stack, so that the encapsulation system covers four of the six faces of said stack assembled, preferably in a continuous manner, so as to obtain an elementary battery, and after step (7), - we deposit successively, on and around, these anode and cathode connections (50): ^■ a first layer of a material loaded with graphite, preferably epoxy resin loaded graphite, ■ a second layer comprising copper metal obtained from an ink loaded with copper nanoparticles deposited on the first layer,  the layers obtained are thermally treated, preferably by infrared flash lamp, so as to obtain a covering of the cathodic and anodic connections (50) by a layer of metallic copper,  optionally, this first stack of terminations is successively deposited on and around, a second stack comprising: ^■ a first layer of a tin-zinc alloy deposited, preferably by immersion in a tin-zinc molten bath to ensure the sealing of the battery at a lower cost, and ^■ a second layer of pure tin based deposited by electrodeposition or a second layer comprising a silver-based alloy, palladium, and copper deposited on this first layer of the second stack. The method of claim 20, wherein the anode and cathode connections are on opposite sides of the stack. 22. An electrochemical device comprising at least one electrolyte thin film according to any one of claims 1 to 7, preferably a lithium ion battery or a supercapacitor.