CN110165236A - A kind of preparation method and applications of bilayer oxide solid electrolyte - Google Patents

Abstract

The invention discloses a preparation method and application of a double-layer oxide solid electrolyte. The double-layer LLZO/LATP multifunctional oxide solid electrolyte includes a dense LLZO ceramic electrolyte layer and a porous LATP solid electrolyte layer. The dense LLZO electrolyte layer is The metal lithium anode is stable and prevents seawater from corroding the metal lithium anode; the porous LATP solid electrolyte layer is stable to seawater and air, and provides an ion-conducting framework for the air cathode reaction. The double-layer oxide solid electrolyte of the present invention can be used to prepare a lithium seawater battery pack, the lithium seawater battery includes a LLZO/LATP multifunctional oxide solid electrolyte, a lithium negative electrode encapsulated in a dense garnet electrolyte layer, and an ion/electronic conductive network air cathode material. Compared with the existing lithium seawater battery, the structural design of the lithium seawater battery of the present invention is more suitable for complex seawater working conditions, and has better working stability.

Description

Preparation method and application of a double-layer oxide solid electrolyte

technical field

The invention relates to the technical field of batteries, in particular to a preparation method and application of a double-layer oxide solid electrolyte.

Background technique

Lithium seawater batteries use metal lithium as the negative electrode and seawater as the positive electrode. It is a new energy system that obtains electrical energy by controlling the electrochemical reaction between lithium and seawater. The battery system can be directly injected into seawater or directly placed in seawater to generate electricity, and has far-reaching application prospects in the fields of deep-sea autonomous underwater vehicles and marine buoy power supplies that require high battery life.

As one of the core components of lithium seawater batteries, the solid electrolyte is the key to achieving high safety and high cycle stability of the battery, while the porous electrode on the positive side needs to have high ion conductivity, wide voltage window and stable chemical properties (especially for seawater and air) and other properties. Garnet-type lithium lanthanum zirconium oxide LLZO (Li ₇ La ₃ Zr ₂ O ₁₂ ) has a wide electrochemical window and is stable to metal lithium. The room temperature ion conductivity can reach 10 ^-3 S/cm, which has a good application prospect. Studies have confirmed that a thin layer of lithium carbonate will form on the surface of LLZO placed in the air for a long time, resulting in a decrease in ionic conductivity. However, the air stability of lithium lanthanum zirconium oxygen is not difficult to overcome. The latest research shows that the use of carbon reduction and other means can effectively restore the passivated surface of lithium lanthanum zirconium oxygen and restore its high ion conductivity. NASICON type LATP (Li _1+x Al _x Ti _2–x (PO ₄ ) ₃ ), LAGP (Li _1+x Al _x Ge _2–x (PO ₄ ) ₃ ) has excellent air stability even in aqueous solution Still maintain stable ionic conductivity. However, since Ti ⁴⁺ and Ge ⁴⁺ in LATP and LAGP will be reduced to Ti and Ge in contact with lithium metal, an intermediate buffer layer needs to be introduced at the lithium metal negative electrode interface to prevent the electrolyte layer from being continuously reduced.

Traditional porous electrodes are composed of catalytic materials, electronically conductive networks, and binders. After being injected into the battery, the electrolyte can penetrate into the air electrode to form a good gas-liquid-solid three-phase reaction interface. Due to the lack of fluidity of the solid electrolyte layer, a good ion-conducting network needs to be actively constructed in the air electrode. In addition to the design of the ion-conducting framework and pore structure in the air electrode, the selection of the electron-conducting network and catalyst also needs to be considered. Judging from the current research status, mechanical mixing of solid electrolyte materials and electronically conductive additives such as conductive carbon is a commonly used method for constructing ionic/electronically conductive networks, and the conductivity uniformity and electrochemical stability of the air cathode obtained need to be improved. The researchers used the solid-state sintering method to construct a composite positive electrode based on the inorganic electronic conductor ITO and the inorganic ionic conductor LBO, which can realize the charge and discharge of solid-state lithium batteries at room temperature. However, the high interface impedance between the inorganic particles leads to large polarization of the battery. Cycle performance is poor. It can be seen that designing and preparing a co-conductive network of lithium ions and electrons in the air cathode is one of the key issues in the construction of high-performance lithium seawater batteries.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a double-layer oxide solid electrolyte and its application, so as to obtain a double-layer solid electrolyte with stable interface and a lithium seawater battery with excellent stability.

For this reason, the invention provides a kind of preparation method of double layer oxide solid state electrolyte, and described method comprises:

(1) Prepare a dense garnet-type (Garnet) LLZO ceramic electrolyte layer;

(2) Prepare a porous LATP solid electrolyte, the material of which includes one or more of the NASICON structure solid electrolyte and the perovskite structure solid electrolyte. The chemical formula of the NASICON structure solid electrolyte is Li _{1+ x} M _x Ti _{2- x} (PO ₄ ) ₃ (M=Al,Sc, Y, La), Li _{1+ x} M _x Ge _{2- x} (PO ₄ ) ₃ (M=Al, Sc, Y, La), the chemical formula of the perovskite structure is Li _{3 x} La _{(2/3)- x (1/3)-2 x} TiO ₃ (0 < x < 0.16), solid electrolyte with NASICON structure such as Li _1.4 Al _0.4 Ti _1.6 (PO ₄ ) ₃ ;

(3) The LATP solid electrolyte nanopowder, template microspheres and binder are prepared in an organic solvent to form a slurry with a suitable viscosity, and evenly coated on the surface of the LLZO ceramic electrolyte layer, and then calcined at a high temperature Build a porous LATP ion-conductive framework on the surface of the LLZO ceramic electrolyte layer to form a double-layer LLZO/LATP multifunctional oxide solid electrolyte;

(4) Loading nano-catalysts on the porous LATP ion-conducting framework of the double-layer LLZO/LATP multifunctional oxide solid electrolyte to obtain an air cathode material with an ion/electronic conducting network.

Preferably, the step (1) includes: preparing the LLZO ceramic electrolyte layer by a vacuum hot pressing method, placing the lithium lanthanum zirconium oxide powder in a graphite mold and compacting it with a tablet press; and then placing it in a vacuum hot pressing furnace , in a vacuum atmosphere at 1140° C. for 0.5-6 hours, and the heating rate is 1-10° C./min; after the sintering is completed, it is cut and polished to form the LLZO ceramic electrolyte layer.

Preferably, the chemical formula of the garnet-type LLZO ceramic electrolyte layer is Li _5+x La ₃ Zr _x M _2-x O ₁₂ , wherein M is Ta, Nb, Hf, Al, Si, Ga, Ge, Sc, Ti , V, Y and Sn, x=0-0.6, the ionic conductivity of the LLZO ceramic electrolyte layer is 1.6×10 ^-3 S/cm, and the relative density is greater than 99.6%.

Preferably, the step (2) includes: using a sol-gel method to prepare a NASICON structure solid electrolyte and a perovskite structure solid electrolyte, mixing the reactant precursors according to the stoichiometric ratio of each solid electrolyte, adding a solvent to dissolve, and adding a chelate The mixture forms a sol-gel, and the solvent is heated and evaporated to obtain a mixed powder; the mixed powder is ground, first sintered at 250-600°C for 2-48 hours, and then ground again, and then sintered at 500-1000°C for 2-48 hours Hours, NASICON structure solid electrolyte powder and perovskite structure solid electrolyte powder can be obtained.

Preferably, the solvent is ethanol or an aqueous solution, the chelating agent is citric acid or tartaric acid, and the prepared solid electrolyte is nano-powder, D50 < 100 nm.

Preferably, in the step (3), the template microspheres are organic microspheres, including but not limited to starch, polystyrene, polymethyl methacrylate; the particle size of the template microspheres is 1-10 μm , the mass ratio of the template microspheres to the LATP solid electrolyte nanopowder is 1:1-10:1; the binder includes but is not limited to at least one of PvDF, PVA, SBR, CMC and PAA , the organic solvent includes but not limited to NMP, ethanol or water; the calcination temperature is 400-800° C., and the calcination time is 1-20 hours.

Preferably, in the step (3), the pore diameter of the porous LATP ion-conductive framework is 1-10 μm, and the porosity is 50-90%.

Preferably, in the step (4), the nano-catalyst includes but not limited to Au, Ru, Pd and Pt.

Preferably, in the step (4), the loading method includes but not limited to atomic layer deposition (ALD), chemical vapor deposition (CVD) or solution immersion method.

The invention also provides the application of the double-layer oxide solid electrolyte in lithium seawater batteries.

Compared with the prior art, the advantages and positive effects of the present invention are: the present invention provides a preparation method and application of a double-layer oxide solid electrolyte, and the LLZO/LATP multifunctional oxide solid electrolyte prepared by the present invention is a dual Layer structure, including dense garnet-type (Garnet) LLZO ceramic electrolyte layer and porous LATP solid electrolyte layer, the dense garnet-type LLZO electrolyte layer is stable to the metal lithium anode and prevents seawater from corroding the metal lithium anode; porous LATP solid The electrolyte layer is stable to seawater and air, and provides an ionically conductive framework for the air cathode reaction. The double-layer oxide solid electrolyte of the present invention can be used to prepare a lithium seawater battery pack, which includes a double-layer LLZO/LATP multifunctional oxide solid electrolyte, a lithium negative electrode encapsulated in a dense garnet electrolyte layer, and an ion/electronic Conductive network of air cathode materials. Compared with the existing lithium seawater battery, the structural design of the lithium seawater battery of the present invention is more suitable for complex seawater working conditions, and has better working cycle stability.

The present invention provides other features and advantages of the present invention will become clearer after reading the detailed description of the present invention in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is the structural representation of the assembled lithium seawater battery of Example 1 of the present invention;

Fig. 2 is the discharge curve diagram of the assembled lithium seawater battery of Example 1 of the present invention;

Fig. 3 is a discharge curve diagram of a lithium seawater battery assembled in Example 2 of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below, and it should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

The invention provides a method for preparing a double-layer oxide solid electrolyte, the method comprising:

(1) Prepare a dense garnet-type (Garnet) LLZO ceramic electrolyte layer by vacuum hot pressing: put the lithium lanthanum zirconium oxide solid electrolyte powder into a mold, and compact it on a tablet machine at 1-5 Mpa; Pressurize 5-10 Mpa in a vacuum atmosphere in a vacuum hot-pressing furnace, hold at 1140°C for 0.5-6 hours, and heat up at a rate of 1-10°C/min; after the sintering is completed, cut and grind it into a disc to obtain a dense LLZO Ceramic electrolyte layer; the ionic conductivity of the LLZO ceramic electrolyte layer is 1.6×10-3S/cm, the thickness is 0.3-1 mm, and the relative density is greater than 99.6%.

(2) Prepare porous LATP solid electrolytes by sol-gel method, such as solid electrolytes with NASICON structure or perovskite structure: mix the reactant precursors according to the stoichiometric ratio of each solid electrolyte, add a solvent to dissolve, and add a chelating agent to form Sol-gel, the solvent is heated and evaporated to dryness to obtain a mixed powder; the mixed powder is ground, first sintered at 250-600°C for 2-48 hours, after grinding again, and then sintered at 500-1000°C for 2-48 hours, The NASICON structure or perovskite structure solid electrolyte powder can be obtained, and the median particle size D50 of the primary particles is < 100 nm.

(3) The LATP solid electrolyte, template microspheres and binder are prepared in an organic solvent to form a slurry with a suitable viscosity, and evenly coated on the surface of the LLZO ceramic electrolyte layer. After high-temperature calcination, it can be constructed on the surface of the LLZO ceramic electrolyte layer The porous LATP ion-conducting framework forms a double-layer LLZO/LATP multifunctional oxide solid electrolyte; the template microspheres are organic microspheres, including but not limited to starch, polystyrene, polymethyl methacrylate; the particle size of the template microspheres The mass ratio of the template microspheres to the LATP solid electrolyte is 1:1-10:1; the calcination temperature is 400-800°C, the calcination time is 1-20 hours, and the binder includes PvDF, PVA, SBR, CMC and PAA, etc., organic solvents include NMP, ethanol and water; slurry viscosity can be 1000-10000 Pa·s.

(4) Loading nanocatalysts on the porous LATP ion-conducting framework of the bilayer LLZO/LATP multifunctional oxide solid electrolyte to obtain an air cathode material with an ion/electron conduction network. Nanocatalysts are non-carbon based, including but not limited to Au, Ru, Pd and Pt. The loading method can be atomic layer deposition (ALD), chemical vapor deposition (CVD) or solution immersion.

In the present invention, the relative density of the dense Garnet-type lithium lanthanum zirconium oxide (LLZO) ceramic electrolyte layer prepared in step (1) is greater than 99.6%, which can effectively block the diffusion of the air component phase metal lithium negative electrode surface, and form a stable Li/Garnet interface, stable to lithium metal. The porous NASICON-type lithium aluminum titanium phosphate (LATP) prepared in step (2) can be used as the ion-conducting network in the seawater cathode and form a stable NASICON/seawater interface, while providing more active sites for the cathode reaction. The double-layer LLZO/LATP multifunctional oxide solid electrolyte prepared in step (3) refers to the use of LLZO stable to metal lithium as the electrolyte directly in contact with metal lithium, and LATP stable to air and water as the electrolyte directly in contact with air; The layered LLZO/LATP multifunctional oxide solid electrolyte meets the requirements of being dense on the metal lithium negative electrode side and porous on the seawater positive electrode side, and has a porous ion-conducting framework with good conductivity and a stable electrolyte/electrode interface. Step (4), based on the double-layer LLZO/LATP multifunctional oxide solid electrolyte, a variety of nanostructured electronically conductive catalysts can be prepared to form a seawater positive electrode with an ion/electronically conductive network, so that the solid-state lithium seawater battery has higher capacity and More excellent cycle stability.

Example 1

The preparation method of the double-layer oxide solid electrolyte of this embodiment includes:

(1) Preparation of Garnet-type lithium lanthanum zirconium oxide (LLZO) ceramic electrolyte layer:

The lithium lanthanum zirconium-based solid electrolyte powder whose chemical formula is Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ is prepared by a solid-state reaction method, and the preparation steps include: according to the molar ratio of Li, La, Zr, and Ta being 6.4:3: 1.4:0.6, choose LiOH, La ₂ O ₃ , ZrO ₂ and Ta ₂ O ₅ as raw materials, in which the excess of LiOH is 5%, ball mill in alcohol for 24 hours and then dry; then calcined at 900°C for 10 hours, the heating rate is 4°C /min, after the sintering is completed, crush and sieve the powder to obtain Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ powder (LLZO), and sieve it to obtain LLZO powder with a particle size of 5 μm;

The LLZO ceramic electrolyte layer was prepared by vacuum hot pressing method. The LLZO powder was mixed into a graphite mold and compacted on a manual tablet press at 4 Mpa; then pressurized at 8 Mpa in a vacuum hot pressing furnace under vacuum atmosphere and kept at 1140 °C for 1 hour, the heating rate is 2°C/min; after the sintering is completed, it is cut and polished into a disc to obtain a dense LLZO ceramic electrolyte layer; the ionic conductivity of the LLZO ceramic electrolyte layer is 1.6×10 ^-3 S/cm, and the thickness is 1 mm, the relative density is greater than 99.6%.

(2) Prepare NASICON type lithium aluminum titanium phosphate (LATP) solid electrolyte; mix the reactant precursors according to the stoichiometric ratio of Li _1.4 Al _0.4 Ti _1.6 (PO ₄ ) ₃ , add pure water to dissolve, add citric acid chelating agent to form For sol-gel, the solvent is heated and evaporated to dryness to obtain a mixed powder; the mixed powder is ground, first sintered at 600°C for 12 hours, after grinding again, and then sintered at 1000°C for 12 hours, the LATP powder can be obtained, once Particles have a median particle size D50 < 100 nm.

(3) Prepare LATP solid electrolyte powder, PP microspheres and binder PvDF in NMP solvent to form a slurry with a suitable viscosity, and evenly coat the surface of the LLZO ceramic electrolyte layer, and then put it into an 80°C blast oven Dry in medium for 12h. Put it in a muffle furnace for high-temperature calcination in an air atmosphere, the calcination temperature is 800°C, and the calcination time is 10 hours; then keep it at 800°C for 5 hours, and the porous LATP ion-conductive framework can be constructed on the surface of the LLZO ceramic electrolyte layer , forming LLZO/LATP multifunctional oxide solid electrolyte. The particle size of PP microspheres is 5 μm, and the mass ratio of PP microspheres to LATP solid electrolyte is 1:1.

(4) Loading nanocatalysts on the porous LATP ion-conducting framework of the LLZO/LATP multifunctional oxide solid electrolyte to obtain an air cathode material with an ion/electron conduction network. In this example, chemical vapor deposition (CVD) is used to load nano-gold catalysts on the porous LATP ion-conductive framework: LLZO/LATP is placed in the chemical vapor deposition reaction chamber, the reaction chamber is evacuated and preheated to the deposition temperature, and the reaction is started. The chamber starts to rotate; the working gas and the nano-gold precursor heated to 100°C are passed into the reaction chamber, and the pressure in the reaction chamber is adjusted to deposit nano-gold; LLZO/LATP of nano-gold Au catalysts.

The double-layer LLZO/LATP multifunctional oxide solid electrolyte of this embodiment can be used to prepare lithium seawater batteries, as shown in Figure 1, one surface of the LLZO ceramic electrolyte layer 1 is a porous LATP ion-conducting framework 4 loaded with nano-gold Au catalyst , on the other surface of the LLZO ceramic electrolyte layer 1 to prepare a metal lithium negative electrode 2, and then use epoxy resin glue 3 to seal the metal lithium negative electrode 2, and the metal lithium negative electrode 2 is located in the stainless steel shell 5, that is, a lithium seawater battery is assembled. Place the lithium seawater battery assembly in 0.1 M simulated seawater. Figure 2 is the discharge curve of the lithium seawater battery based on the LLZO/LATP-Au of this embodiment. It can be seen that the double-layer LLZO/LATP of this embodiment is more Under the encapsulation of functional oxide solid electrolyte, the battery discharge platform is maintained at around 2.85V, and the stability time exceeds 50 days, which reflects the good sealing and stability of the double-layer solid electrolyte in lithium seawater batteries.

Example 2

The preparation method of the double-layer oxide solid electrolyte of this embodiment includes:

(1) Preparation of Garnet-type lithium lanthanum zirconium oxide (LLZO) ceramic electrolyte layer:

The lithium lanthanum zirconium-based solid electrolyte powder whose chemical formula is Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ is prepared by a solid-state reaction method, and the preparation steps include: according to the molar ratio of Li, La, Zr, and Ta being 6.4:3: 1.4:0.6, choose LiOH, La ₂ O ₃ , ZrO ₂ and Ta ₂ O ₅ as raw materials, in which the excess of LiOH is 5%, ball mill in alcohol for 24 hours and then dry; then calcined at 900°C for 10 hours, the heating rate is 4°C /min, after the sintering is completed, crush and sieve the powder to obtain Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ powder (LLZO), and sieve it to obtain LLZO powder with a particle size of 5 μm;

The LLZO ceramic electrolyte layer was prepared by vacuum hot pressing method, the LLZO powder was mixed into the graphite mold, and compacted at 5 MPa on a manual tablet press; then pressurized at 10 MPa in a vacuum hot pressing furnace under vacuum atmosphere, and kept at 1140 ° C for 1 hour , the heating rate is 2°C/min; after the sintering is completed, it is cut and polished into a disc to obtain a dense LLZO ceramic electrolyte layer; the ionic conductivity of the LLZO ceramic electrolyte layer is 1.6×10 ^-3 S/cm, and the thickness is 0.5 mm, the relative density is greater than 99.6%.

(2) Prepare perovskite-type Li _0.33 La _0.56 TiO ₃ (LLTO) solid electrolyte powder; mix the reactant precursors according to the stoichiometric ratio of Li _0.33 La _0.56 TiO ₃ , add water to dissolve, and add tartaric acid chelating agent to form Sol-gel, heat the solvent and evaporate to dryness to obtain mixed powder; grind the mixed powder, first sinter at 600°C for 10 hours, after grinding again, and then sinter at 1100°C for 12 hours, you can get LLTO powder, once Particles have a median particle size D50 < 100 nm.

(3) Prepare LATP solid electrolyte powder, PS microspheres and binder PvDF in NMP solvent to form a slurry with a suitable viscosity, and evenly coat the surface of the LLZO ceramic electrolyte layer, and then put it in an 80°C blast oven Dry for 12h. Put it in a muffle furnace for high-temperature calcination in an air atmosphere, the calcination temperature is 800 ℃, and the calcination time is 10 hours; then it is kept at 400 ℃ for 1-10 hours, and the porous LLTO ion can be constructed on the surface of the LLZO ceramic electrolyte layer The conductive skeleton forms a double-layer LLZO/LLTO multifunctional oxide solid electrolyte; the particle size of the template microspheres is 6 μm, and the mass ratio of PS microspheres to LLTO solid electrolyte is 2:1;

(4) Loading nanocatalysts on the porous LLTO ion-conducting framework of the bilayer LLZO/LLTO multifunctional oxide solid electrolyte to obtain an air cathode material with an ion/electron conduction network. In this example, chemical vapor deposition (CVD) is used to load nano-platinum Pt catalyst on the porous LATP ion-conducting framework: LLZO/LATP is placed in the chemical vapor deposition reaction chamber, the reaction chamber is evacuated and preheated to the deposition temperature, and the start-up The reaction chamber starts to rotate; the working gas and the nano-Pt precursor heated to 110°C are passed into the reaction chamber, and the pressure in the reaction chamber is adjusted for deposition; after the reaction is completed, the reaction chamber stops rotating, and the load can be obtained after the reaction chamber is cooled to room temperature. LLZO/LLTO of nano-platinum Pt.

The double-layer LLZO/LATP multifunctional oxide solid electrolyte of this embodiment can be used to prepare lithium seawater battery. One surface of the LLZO ceramic electrolyte layer is a porous LATP ion-conductive framework loaded with nano-platinum Pt catalyst, and the other surface of the LLZO ceramic electrolyte layer A metal lithium negative electrode is prepared on the surface, and then the metal lithium negative electrode is sealed with epoxy resin glue, that is, a lithium seawater battery is assembled. The lithium seawater battery device is placed in 0.1M simulated seawater. Fig. 3 is the discharge curve of the lithium seawater battery based on the LLZO/LAT-Pt of the present embodiment. It can be seen that the double-layer LLZO/LATP of the present embodiment is more Under the encapsulation of functional oxide solid electrolyte, the battery discharge platform is maintained at around 2.8V, and the stability time exceeds 60 days, which reflects the good sealing and stability of the double-layer solid electrolyte in lithium seawater batteries.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art can still understand the foregoing embodiments. Modifications are made to the technical solutions described, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions claimed in the present invention.

Claims (10)

1. a kind of preparation method of bilayer oxide solid electrolyte, which is characterized in that the described method includes:

(1) fine and close carbuncle type (Garnet) LLZO ceramic electrolyte layer of preparation；

(2) porous LATP solid electrolyte is prepared, material includes that NASICON structure solid electrolyte and perovskite structure are solid One or more of body electrolyte, NASICON structure solid electrolyte chemical formula are Li_1+x M_xTi_2-x (PO₄)₃ (M=Al, Sc, Y, La)、Li_1+x M_xGe_2-x (PO₄)₃The chemical formula of (M=Al, Sc, Y, La), perovskite structure is Li_3x La_{(2/3)-x (1/3)-2x} TiO₃ (0 < x < 0.16)；

(3) the LATP solid electrolyte nano-powder, template microsphere and binder viscosity is deployed into organic solvent to close Suitable slurry, and it is coated uniformly on the LLZO ceramic electrolyte layer surface, it can be in the LLZO ceramic electrical through high-temperature calcination It solves matter layer surface and constructs porous LATP ionic conduction skeleton, form the multi-functional solid oxide electrolyte of bilayer LLZO/LATP；

(4) on the porous LATP ionic conduction skeleton of the multi-functional solid oxide electrolyte of the bilayer LLZO/LATP Nanocatalyst is loaded, obtains that there is ion/electronic conduction network air cathode material.

2. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

The step (1) includes:

The LLZO ceramic electrolyte layer is prepared using vacuum hot-pressing, lithium lanthanum zirconium oxygen powder is placed in graphite jig and uses tabletting Machine compacting；Be subsequently placed in vacuum hotpressing stove, under vacuum atmosphere in 1140 DEG C heat preservation 0.5-6 hours, heating rate be 1-10 DEG C/ min；It is cut after the completion of to be sintered and is polished into the LLZO ceramic electrolyte layer.

3. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

The chemical formula of the carbuncle type LLZO ceramic electrolyte layer is Li_5+xLa₃Zr_xM_2-xO₁₂, wherein M be Ta, Nb, Hf, Al, One of Si, Ga, Ge, Sc, Ti, V, Y and Sn, x=0-0.6；

The ionic conductivity of the LLZO ceramic electrolyte layer is 1.6 × 10^-3S/cm, relative density are greater than 99.6%.

4. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

The step (2) includes:

NASICON structure solid electrolyte and perovskite structure solid electrolyte are prepared using sol-gal process, according to each solid The stoichiometric ratio of electrolyte mixes reactant presoma, and solvent dissolution is added, and chelating agent is added and forms collosol and gel, will be molten Agent heating is evaporated to obtain mixed powder；Mixed powder is ground, is first sintered 2-48 hours at 250-600 DEG C, after regrinding, It is sintered 2-48 hours at 500-1000 DEG C again, NASICON structure solid electrolyte powder can be obtained and perovskite structure is solid Body electrolyte powder.

5. the preparation method of bilayer oxide solid electrolyte according to claim 4, which is characterized in that

The solvent is ethyl alcohol or aqueous solution, and the chelating agent is citric acid or tartaric acid, and the solid electrolyte being prepared is Nano-powder, the nm of D50 < 100.

6. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

In the step (3),

The template microsphere is organic micro-spheres, including but not limited to starch, polystyrene, polymethyl methacrylate；

The partial size of the template microsphere is 1-10 μm, the quality of the template microsphere and the LATP solid electrolyte nano-powder Than for 1:1-10:1；

The binder includes but is not limited at least one of PvDF, PVA, SBR, CMC and PAA, and the organic solvent includes But it is not limited to NMP, ethyl alcohol or water；

Calcination temperature is 400-800 DEG C, and calcination time is 1-20 hours.

7. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

In the step (3), the aperture of the porous LATP ionic conduction skeleton is 1-10 μm, porosity 50-90%.

8. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

In the step (4), the nanocatalyst includes but is not limited to Au, Ru, Pd and Pt.

9. the preparation method of bilayer oxide solid electrolyte according to claim 1, which is characterized in that

In the step (4), carrying method include but is not limited to atomic layer deposition method (ALD), chemical vapour deposition technique (CVD) or Solution dipping method.

10. bilayer oxide solid electrolyte according to claim 1 to 9 is in preparing lithium seawater battery Using.