CN106058305B

CN106058305B - Method for preparing miniature all-solid-state thin-film lithium ion battery in situ by using PLD (pulsed laser deposition)

Info

Publication number: CN106058305B
Application number: CN201610664363.4A
Authority: CN
Inventors: 钱婧; 王亚平; 包吴奇
Original assignee: Gotion High Tech Co Ltd
Current assignee: Gotion High Tech Co Ltd
Priority date: 2016-08-12
Filing date: 2016-08-12
Publication date: 2019-02-05
Anticipated expiration: 2036-08-12
Also published as: CN106058305A

Abstract

The invention discloses a method for in-situ preparation of a miniature all-solid-state thin-film lithium ion battery by using PLD, belonging to the technical field of lithium ion batteries, comprising the following steps: 1) pretreatment of substrate: cleaning the silicon dioxide substrate and drying it 2) Preparation of battery: PLD was used to sequentially deposit metal platinum as current collector, lithium cobalt oxide as positive electrode, lithium phosphorus oxynitride as electrolyte, and graphene as electron penetrator on the silica substrate cleaned in step 1). The transparent transition layer and graphite are used as the negative electrode film. The miniature all-solid-state thin-film lithium battery structure of the present invention adopts PLD in-situ deposition, and at the same time, graphene is introduced between the negative electrode graphite and the solid electrolyte as an electron transport transition layer, which can effectively improve the battery performance and cycle times, while ensuring the heat of the miniature lithium battery. Stability and welding temperature requirements.

Description

A method of miniature solid-State Thin Film Li-Ion Batteries being prepared in situ with PLD

Technical field

The present invention relates to a kind of preparation methods of lithium ion battery, and in particular to it is a kind of be prepared in situ with PLD it is miniature complete solid The method of state film lithium ion battery, belongs to technical field of lithium ion.

Background technique

With the continuous development of the technical fields such as microelectronics, communication, medical treatment implantation, military and radio frequency identification, Where corresponding miniaturization of electronic products, micromation, the integrated trend for having become global technology development.This carrys out battery Say it is primary innovation and challenge, it is meant that the demand to minicell will increasingly increase.Currently, actively developing research both at home and abroad Minicell type has lithium ion battery, zinc-nickel cell, solar battery, fuel cell etc..Wherein, miniature lithium ion battery because The advantages such as high-energy density, high voltage, long circulation life, high safety performance, the extensive concern by researcher.But current lithium Ion battery mostly uses greatly liquid electrolyte, there is a problem of that easily leakage, perishable, security reliability is lower.In contrast, Miniature solid-State Thin Film Li-Ion Batteries are because it uses solid electrolyte, and the thermal stability that has had, there is no leakage and electricity It solves liquid and problem is lost, there is higher safety coefficient, therefore show one's talent in numerous Study on Li-ion batteries.In addition to this, The electrode and electrolyte of miniature solid-State Thin Film Li-Ion Batteries are solid-state, be omitted diaphragm, electrolyte, electrolytic salt and The use of the materials such as binder simplifies the preparation process of lithium ion battery.Therefore, miniature solid-State Thin Film Li-Ion Batteries, It is expected in future portable electronic equipment, defence equipment and microelectromechanical systems (before having a wide range of applications in terms of MEMS Scape

Pulsed laser deposition technique (Pulsed Laser Deposition, PLD) is used as a kind of vacuum coating technology, quilt It is widely used in film preparation.Its working principle is exactly laser irradiation on target, and the particle in target becomes after ablation Plasma is from target to substrate transport, and cohesion nucleation forms a film on substrate.PLD has behaviour compared with other coating techniques Make the advantages such as simple, parameter easy-regulating；In addition, by selecting different targets, the sputtering parameter for regulating and controlling instrument can be prepared in situ The multilayer films of different pattern and different-thickness；At the same time, target and film composition can guarantee identical chemistry Metering ratio.Currently, PLD technology is successfully used to prepare LiCoO₂/Li_3.4V_0.6Si_0.4O₄/ SnO solid film lithium battery Structure or anode film material LixMn₂O₄Or rich lithium phase Li₂MnO₃Film (Electrochemistry Communications, 6(2004)417-421；Applied Surface Science,197-198(2002)516-521；Journal of Materials Chemistry A,2014,2(7):2283-2289).The smooth and cause by the electrolytic thin-membrane of PLD preparation Close, researcher also analyzes that show that film composition is able to maintain almost consistent with target component.After charge and discharge cycles, electrolyte Film still keeps homogeneity, and still smooth defect free cell interface structure (electrolyte/anode, electrolyte/cathode) occurs.This Outside, the hull cell prepared by PLD film deposition techniques can be obviously improved the interface impedance (lithium ion in solid electrolyte Conductivity is compared in liquid phase electrolyte or slightly lower, so that ohmic resistance be caused to increase).But pass through the PLD technology The film lithium ion battery (Electrochemistry Communications, 6 (2004) 417-421) of preparation is by the After charge and discharge cycles, capacity is gradually decayed, and discharge capacity only has first time circulation volume after 100 circulations 45%, the mainly Li due to SnO and insertion⁺Reaction generates Sn-Li alloy and Li₂Caused by O.In addition, there is researcher by PLD Be combined from different sputtering technologies and realize continuous coating: i.e. PLD deposits anode LiCoO₂, radio frequency and direct magnetic control deposit LiPON, heat Evaporated metal cathode of lithium (Solid State Ionics, 285 (2016) 118-121).Although this combination deposition technique can be with Realize whole vacuum preparation, interfacial contact is good, and cell manufacturing process not ingress of air, but this method is excessively cumbersome, no Conducive to industrialized large-scale production.Furthermore current researcher mostly uses metal when preparing solid-State Thin Film Li-Ion Batteries Lithium is as cathode, but lithium fusing point is lower (180 DEG C), the heatproof (250 with solder reflow technology in micro cell and integrated circuit DEG C) require incompatible, it is easy to form dead lithium in cycle charge-discharge.Furthermore lithium metal needs harshness to oxygen and water vapor sensitive Encapsulation technology keep stablize, seriously constrain the large-scale promotion application of full solid thin film lithium electricity.Therefore, develop a kind of prepare It is technically simple, realize that multiple circulation volume is kept, while meet the miniature full solid thin film lithium of thermal stability high temperature resistant requirement from Sub- battery, is of great significance.

Summary of the invention

Miniature full solid thin film is prepared in situ with PLD in view of the above existing problems in the prior art, the present invention provides a kind of Battery performance and cycle-index can be improved in the method for lithium ion battery, while guaranteeing thermal stability and the welding of miniature lithium electricity Heatproof requirement.

To achieve the goals above, what the present invention used a kind of is prepared in situ miniature full solid thin film lithium-ion electric with PLD The method in pond, comprising the following steps:

1) pretreatment of substrate: silicon dioxide substrates are cleaned up, and dried for standby；

2) metal platinum work the preparation of battery: is sequentially depositing in the silicon dioxide substrates cleaned up in step 1) with PLD Make as electrolyte, graphene as penetration of electrons transition zone and graphite for collector, cobalt acid lithium as anode, LiPON For negative film.

As an improvement, in the step 1), specific cleaning step are as follows:

(i) silicon dioxide substrates are cleaned by ultrasonic 20min in acetone；

(ii) then it is cleaned by ultrasonic 20min in ethanol；

(iii) it is cleaned several times with deionized water.

As an improvement, the preparation of the step 2) battery, specifically includes a) preparation of target and b) produced in situ micro electric Each layer film in pond；

The preparation of a) target:

When preparing electrolyte lithium phosphorous oxynitride using PLD, the target used is by Li₃PO₄Powder tabletting is sintered；

When depositing cobalt acid lithium as anode, the target used passes through LiCoO₂Tabletting sintering is made；

When depositing graphene as penetration of electrons transition zone, the target used is made up of graphene tabletting sintering；

When depositing graphite as negative film, the target used is made up of graphite composite powder tabletting sintering.

As an improvement, each layer film of b) the produced in situ minicell, specifically includes the following steps:

(i) one layer of metal platinum is plated as plus plate current-collecting body using PLD on the silicon wafer after cleaning-drying；

(ii) on same PLD instrument, LiCoO is utilized₂Target in-situ deposition anode LiCoO₂Film；

(iii) on same PLD instrument, PLD deposition solid electrolyte LiPON is utilized；

(iv) on same PLD instrument, penetration of electrons transport layer graphene film is deposited；

(v) on same PLD instrument, graphite is deposited as negative film.

As an improvement, step (ii) specific steps are as follows:

LiCoO₂Target is made up of dry-pressing powder in 900 DEG C of sintering 5h, and deposition process is passed through certain oxygen, pressure control In 0.13Pa, 400 DEG C of underlayer temperature；Laser frequency is 3Hz, laser energy density 1.0Jcm^-2。

As an improvement, step (iii) specific steps are as follows:

When preparing solid electrolyte LiPON film using PLD technology, Li₃PO₄Target is made in 600 DEG C of sintering 5h, deposition When be passed through N₂, air pressure is in 0.5Pa, laser frequency 6Hz, laser energy density 2.5Jcm^-2, room temperature deposition.

As an improvement, step (iv) specific steps are as follows: be filled with protective atmosphere Ar first, air pressure is in 0.5Pa, laser frequency Rate is 3Hz, laser energy density 1.0Jcm^-2, room temperature deposition graphene film.

As an improvement, step (v) specific steps are as follows: deposition graphite as negative film when, the atmosphere used for Ar, Air pressure is in 0.1Pa, laser frequency 6Hz, laser energy density 2.0Jcm^-2, room temperature deposition.

In addition, the present invention also provides miniature full solid thin film lithium-ion electrics made from a kind of any of the above-described the method Pond.

Compared with prior art, the invention has the following beneficial effects:

1) the miniature solid-State Thin Film Li-Ion Batteries substitute traditional lithium metal as negative film using graphite, avoid Reacting between lithium metal and other metals, while also avoiding the stroke of dead cathode of lithium, substantially increase film all-solid-state The stability of lithium ion battery.

2) using having high conductivity, the graphene that thermal conductivity is good, insensitive to environment, which is introduced by PLD In the material system of pond, it is placed between electrolyte and graphite cathode as penetration of electrons transport layer, it can be achieved that the quick penetration of electronics, The chemical property of All-solid film batteries not only can be improved in this graphene/graphite cathode composite construction, but also guarantees The thermostabilization of hull cell.

3) preparation method is quick and easy, not only avoid with air and moisture, but also optimize solid-state thin-film battery Preparation flow and enhancing circulating battery period.

4) by miniature solid-State Thin Film Li-Ion Batteries prepared by PLD technology be expected to future portable electronic equipment, Defence equipment and microelectromechanical systems (MEMS) etc. have a wide range of applications.

Detailed description of the invention

Fig. 1 is schematic illustration of the present invention using pulse laser deposition；

Fig. 2 is that miniature All-solid film batteries structure section schematic diagram is made in the present invention；

In figure: 1, laser, 2, lens, 3, optical beam scanner, 4, power supply, 5, substrate heater, 6, substrate, 7, plumage brightness, 8, vacuum chamber, 9, target, 10, graphite, 11, LiPON, 12, metal platinum, 13, silicon dioxide substrates, 14, cobalt acid lithium, 15, stone Black alkene.

Specific embodiment

In order to make the objectives, technical solutions and advantages of the present invention clearer, below by accompanying drawings and embodiments, to this Invention is further elaborated.However, it should be understood that the specific embodiments described herein are merely illustrative of the present invention, The range being not intended to restrict the invention.

Unless otherwise defined, all technical terms and scientific terms used herein are led with technology of the invention is belonged to The normally understood meaning of the technical staff in domain is identical, and term as used herein in the specification of the present invention is intended merely to retouch State the purpose of specific embodiment, it is not intended that in the limitation present invention.

The pulse laser deposition principle used in the method for the present invention, as shown in Figure 1, lens 2 are passed through by laser 1, then By optical beam scanner 3 by laser bombardment on target 9, the electrodeposition substance fallen by laser bombardment on the substrate 6, and substrate 6 It is heated using plumage brightness 7, power supply 4 and substrate heater 5, it is ensured that deposition effect, wherein bombardment, deposition process are all in vacuum Room 8 carries out.

Embodiment one

A method of miniature solid-State Thin Film Li-Ion Batteries being prepared in situ with PLD, specifically includes the following steps:

1) pretreatment of substrate:

A) firstly, silicon dioxide substrates 13 are cleaned by ultrasonic, the step of cleaning are as follows: (i) is cleaned by ultrasonic in acetone 20min；(ii) it is cleaned by ultrasonic 20min in ethanol, is then cleaned several times with deionized water again；

2) preparation of target:

Electrolyte Li is prepared using PLD₃PO_4-xN_x(LiPON) when film, the target used is by Li₃PO₄Powder tabletting is burnt It ties, for positive LiCoO₂Film, electron transfer layer graphene and cathode graphite linings, used in target pass through LiCoO₂, graphene and graphite composite powder tabletting sintering be made；

3) each layer film of growth in situ minicell:

Miniature All-solid film batteries structure section schematic diagram is as shown in Figure 2:

(i) one layer of metal platinum 12 (deposition thickness 100nm) is plated as anode using PLD on the silicon wafer after cleaning-drying Collector metallic film；

(ii) on same PLD instrument, LiCoO is utilized₂14 film (thickness of target in-situ deposition anode cobalt acid lithium 200nm)；

Wherein, LiCoO₂Target is made up of dry-pressing powder sintering (900 DEG C of sintering 5h), and deposition process is passed through certain oxygen Gas, pressure control is in 0.13Pa, and 400 DEG C of underlayer temperature；Laser frequency is 3Hz, laser energy density 1.0Jcm^-2；

(iii) on same PLD instrument, PLD deposition solid electrolyte Li is utilized₃PO_4-xN_x(11 film of LiPON, The film deposition thickness is 1 μm)；

When preparing solid electrolyte LiPON film using PLD technology, target Li₃PO₄(600 DEG C of sintering 5h), deposition When be passed through N₂, air pressure is in 0.5Pa, laser frequency 6Hz, laser energy density 2.5Jcm^-2, room temperature deposition；

(iv) on same PLD instrument, 15 film of penetration of electrons transport layer graphene is deposited, with a thickness of 100nm；

It is filled with protective atmosphere Ar first, air pressure is in 0.5Pa, laser frequency 3Hz, laser energy density 1.0Jcm^-2, room Temperature deposition；

(v) on same PLD instrument, deposition graphite 10 is used as cathode (graphite linings are with a thickness of 500nm), the atmosphere of use For Ar, air pressure is in 0.1Pa, laser frequency 6Hz, laser energy density 2.0Jcm^-2, room temperature deposition.

In whole preparation process, every kind of target is screwed in target button, base substrate also screws in substrate button, closes chamber Door, cavity is vacuumized with mechanical pump and molecular pump.When intracavitary vacuum is evacuated to 10^-4Pa is passed through corresponding reaction gas, and adjusts To certain air pressure；Target and substrate rotating switch are opened, target revolving speed is adjusted and is rotated in 120rpm, substrate revolving speed is in 60rpm. Laser energy density and frequency values are inputted on control panel, are opened laser and are started deposition process；After reaching sedimentation time, close Laser and rotating switch are closed, is cooled to room temperature taking-up sample to underlayer temperature, is placed in dry sealer, in case carrying out structure Morphology characterization or electrochemical property test.If not wanting test item, then sample is not taken out, only need to close laser, adjusted Whole next target location and deposition parameter start deposition process, until the preparation of last negative film terminates.

Embodiment two

Comparative test.(iv) step in embodiment one is omitted, (v) step makees following adjustment, remaining step is consistent:

(v) on same PLD instrument, deposit cathode graphite linings (600nm), use atmosphere for Ar, air pressure in 0.1Pa, Laser frequency is 6Hz, laser energy density 2.0Jcm^-2, room temperature deposition.

Embodiment three

Comparative test.(v) step in embodiment one is omitted, (iv) step makees following adjustment, remaining step is consistent:

(iv) it on same PLD instrument, deposits negative metal lithium layer film (600nm).Atmosphere is Ar, and air pressure exists 0.1Pa, laser frequency 6Hz, laser energy density 2.0Jcm^-2, room temperature deposition.

Example IV

Using the structure and morphology and chemical property of miniature solid-State Thin Film Li-Ion Batteries made from the method for the present invention Characterization:

Using the impedance spectra of ac impedance spectroscopy and charge and discharge electric cabinet test solid film lithium battery, Cyclic voltamogram curve And charging and discharging curve, it is heavy using X-ray diffractometer analysis PLD by scanning electron microscope monitoring cell structure and surface topography Long-pending film phase structure disperses spectrum test interface chemical valence state by X-ray energy to analyze the thermal stability of battery structure.

The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention Made any modification, equivalent replacement or improvement etc., should all be included in the protection scope of the present invention within mind and principle.

Claims

1. a method for preparing miniature all-solid-state thin-film lithium-ion battery in situ with PLD, is characterized in that, comprises the following steps:

1) Pretreatment of the substrate: the silicon dioxide substrate (13) is cleaned and dried for use;

2) Preparation of the battery: PLD is used to sequentially deposit metal platinum (12) as the current collector, lithium cobalt oxide (14) as the positive electrode, lithium phosphorus oxynitride ( 11) as electrolyte, graphene (15) as electron penetration transport layer, and graphite (10) as negative electrode film;

The step 2) the preparation of the battery specifically includes a) the preparation of the target material and b) the in-situ production of each layer of the micro-battery thin film;

The preparation of the a) target material:

When using PLD to prepare the electrolyte lithium phosphorus oxynitride (11), the target material used is formed by pressing and sintering Li ₃ PO ₄ powder;

When depositing lithium cobalt oxide (14) as a positive electrode, the target material used is made by pressing LiCoO ₂ and sintering;

When the graphene (15) is deposited as the electron penetration transport layer, the target material used is made by sintering the graphene sheet;

When the graphite (10) is deposited as the negative electrode film, the target material used is made by pressing and sintering graphite powder;

The b) in-situ production of each layer of thin film of the micro-battery specifically includes the following steps:

(i) using PLD to coat a layer of metal platinum (12) on the cleaned and dried silicon wafer as a positive electrode current collector;

(ii) In situ deposition of positive LiCoO thin films using LiCoO targets _on the same PLD instrument _;

(iii) Using PLD to deposit solid electrolyte LiPON on the same PLD instrument;

(iv) On the same PLD instrument, deposit the electron penetration transport layer graphene film;

(v) on the same PLD instrument, depositing graphite (10) as a negative electrode film;

Described step (ii) concrete steps are:

The LiCoO ₂ target is made by sintering dry-pressed powder at 900°C for 5h. During the deposition process, a certain amount of oxygen is introduced, the air pressure is controlled at 0.13Pa, and the substrate temperature is 400°C; the laser frequency is 3Hz, and the laser energy density is 1.0Jcm ^-2 ;

Described step (iii) concrete steps are:

When the solid electrolyte LiPON thin film was prepared by PLD technology, the Li ₃ PO ₄ target was sintered at 600 ℃ for 5h, and N ₂ was introduced during deposition, the gas pressure was 0.5Pa, the laser frequency was 6Hz, and the laser energy density was 2.5Jcm ^-2 . room temperature deposition;

The specific steps of the step (iv) are as follows: firstly, the protective atmosphere Ar is charged, the air pressure is 0.5Pa, the laser frequency is 3Hz, the laser energy density is 1.0Jcm ⁻² , and the graphene film is deposited at room temperature;

The specific steps of the step (v) are: when the graphite (10) is deposited as the negative electrode film, the atmosphere used is Ar, the gas pressure is 0.1Pa, the laser frequency is 6Hz, the laser energy density is 2.0Jcm ⁻² , and the deposition is at room temperature.

2. a kind of method for preparing miniature all-solid-state thin-film lithium-ion battery in situ with PLD according to claim 1, is characterized in that, in described step 1), concrete cleaning step is:

(i) ultrasonically cleaning the silica substrate (13) in acetone for 20min;

(ii) then ultrasonically cleaned in ethanol for 20min;

(iii) Rinse several times with deionized water.

3. A miniature all-solid-state thin-film lithium-ion battery prepared by the method of any one of claims 1-2.