阅读说明：本技术 一种高温型固态电解质及其制备方法和应用 (High-temperature solid electrolyte and preparation method and application thereof ) 是由 陈人杰 屈雯洁 邢易 陈楠 闫明霞 温子越 吴锋 于 2020-04-10 设计创作，主要内容包括：本发明涉及电解质材料技术领域,具体涉及一种高温型固态电解质及其制备方法和应用。本发明提供了一种高温型固态电解质,所述高温型固态电解质包括细菌纤维素膜、二氧化硅纳米颗粒和离子液体电解质；所述细菌纤维素膜具有三维网状结构,所述二氧化硅纳米颗粒和离子液体电解质分布在所述细菌纤维素膜的三维网状结构内部；所述离子液体电解质包裹在二氧化硅纳米颗粒表面。本发明提供的高温型固态电解质,能够发挥出所有成分的各自优势,具备优异的综合性能,该体系在宏观上呈现出高热稳定性和尺寸稳定性,在微观结构上内部离子液体均匀包裹在纳米颗粒外表面,形成连续液相,为离子的迁移和传导提供快速通道。(The invention relates to the technical field of electrolyte materials, in particular to a high-temperature solid electrolyte and a preparation method and application thereof. The invention provides a high-temperature solid electrolyte, which comprises a bacterial cellulose membrane, silicon dioxide nanoparticles and an ionic liquid electrolyte; the bacterial cellulose membrane is provided with a three-dimensional network structure, and the silica nanoparticles and the ionic liquid electrolyte are distributed inside the three-dimensional network structure of the bacterial cellulose membrane; the ionic liquid electrolyte is coated on the surface of the silica nanoparticle. The high-temperature solid electrolyte provided by the invention can exert respective advantages of all components, has excellent comprehensive performance, macroscopically presents high thermal stability and dimensional stability, and the internal ionic liquid is uniformly coated on the outer surface of the nano-particles on a microstructure to form a continuous liquid phase, thereby providing a rapid channel for the migration and conduction of ions.)

1. A high temperature type solid electrolyte, comprising a bacterial cellulose membrane, silica nanoparticles, and an ionic liquid electrolyte; the bacterial cellulose membrane is provided with a three-dimensional network structure, and the silica nanoparticles and the ionic liquid electrolyte are distributed inside the three-dimensional network structure of the bacterial cellulose membrane; the ionic liquid electrolyte is coated on the surface of the silica nanoparticle.

2. The high-temperature solid electrolyte according to claim 1, wherein the ionic liquid electrolyte is a mixed solution of an organic lithium salt and an ionic liquid; the molar concentration of the organic lithium salt in the ionic liquid electrolyte is 0.5-1.5 mol/L; the molar ratio of the ionic liquid to the silicon dioxide nanoparticles is 0.5-2: 1; the average particle size of the silicon dioxide nanoparticles is 10-50 nm.

3. The high temperature solid state electrolyte of claim 1 or 2, wherein the organic lithium salt comprises one or more of lithium bistrifluoromethanesulfonylimide, lithium bifluorosulfonylimide, lithium perfluoroethanesulfonyl imide, and lithium perfluoromethanesulfonyl methide.

4. The high temperature solid state electrolyte according to claim 1 or 2, wherein the ionic liquid comprises N-methyl, propyl pyrrolidine bistrifluoromethylsulfonyl imide salt, N-methyl, butyl pyrrolidine bistrifluoromethylsulfonyl imide salt, N-methyl, propyl piperidine bistrifluoromethylsulfonyl imide salt, N-methyl, butyl piperidine bistrifluoromethylsulfonyl imide salt, N-methyl, propyl piperidine bistrifluoromethylsulfonyl imide salt, 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt, 1-propyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt, 1-butyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt, 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt, N-methyl, butyl-3-pyrrolidinium bistrifluoromethylsulfonyl imide salt, N-methyl, butyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt, N-, One or more of 1-propyl-3-methylimidazolium bis-fluoromethanesulfonylimide salts and 1-butyl-3-methylimidazolium bis-fluoromethanesulfonylimide salts.

5. A high-temperature solid-state electrolyte as claimed in claim 1, wherein the silica nanoparticles are generated by hydrolysis of silicate-based organic materials by in-situ sol-gel reaction.

6. A high-temperature solid-state electrolyte according to claim 1 or 5, wherein the silicate-type organic substance comprises one or more of methyl silicate, ethyl silicate, propyl silicate, isopropyl silicate and butyl silicate.

7. A method for preparing a high-temperature solid electrolyte as claimed in claims 1 to 6, comprising the steps of:

carrying out first mixing on an organic lithium salt and an ionic liquid to obtain an ionic liquid-organic lithium salt solution;

carrying out second mixing on the ionic liquid-organic lithium salt solution and the silicate organic matter to obtain a mixed solution;

dipping the bacterial cellulose membrane into the mixed solution to obtain a dipped bacterial cellulose membrane;

and dropwise adding formic acid into the bacterial cellulose impregnated membrane, standing and solidifying to obtain the high-temperature solid electrolyte.

8. The preparation method according to claim 7, wherein the first mixing and the second mixing are independently performed under stirring conditions, and the stirring rate is independently 300 to 500 r/min; the stirring time is independently 3-10 min.

9. The preparation method according to claim 7, wherein the time for the immersion is 12 to 48 hours; the standing and curing time is 4-7 days; the temperature of standing and curing is 70-100 ℃.

10. Use of the high-temperature solid electrolyte according to any one of claims 1 to 6 or the high-temperature solid electrolyte obtained by the preparation method according to any one of claims 7 to 9 in a lithium battery.

Technical Field

The invention relates to the technical field of electrolyte materials, in particular to a high-temperature solid electrolyte and a preparation method and application thereof.

Background

With the change of market demands at home and abroad and the rapid development of various industries, the traditional secondary battery can not meet the requirements of special extreme working temperatures in the fields of oil well exploration (200-300 ℃), intelligent robots (> 120 ℃), military communication (350-600 ℃), aerospace (> 300 ℃) and the like due to fixed normal-temperature working conditions, so that the development of the high-temperature secondary battery with safety, reliability and long service life is urgent. Among them, the thermal stability of the electrolyte determines the temperature range and safety that the battery can endure when operating. At present, most of electrolytes of commercialized traditional lithium secondary batteries are carbonate solutions of lithium hexafluorophosphate, and the electrolytes are unstable, flammable and explosive at high temperature, easy to leak and the like, so that thermal runaway of the secondary batteries in a high-temperature environment is easily caused.

In recent years, researchers have proposed a novel composite electrolyte composed of an ionic liquid and a Solid Framework, wherein one part is an ionic liquid electrolyte with thermal stability and mainly provides a fast conduction path for migration of ions, and the other part is a porous Solid network Framework and mainly provides a fixed support and mechanical strength for the composite electrolyte and an attachment site for the ionic liquid electrolyte, and the prior report "A Metal-Organic-Framework-based electrolyte with nanowet interface for High-Energy-Density-Solid-state lithium Battery" (Adv. Mater.2018,30(2):1704436) discloses a Solid electrolyte composed of an ionic liquid and a Solid Framework, and the room-temperature ionic conductivity of the Solid electrolyte is 3 × 10^-4S/cm, and the working temperature range can be expanded to-20-150 ℃.

However, the electrochemical performance of the composite solid electrolyte is easily affected by the shape, size and other factors of the solid framework material, and when the composite solid electrolyte works at high temperature, solid-liquid phase separation in a composite system is easily generated, so that the mechanical strength and interface stability of the composite solid electrolyte are poor, and further, the secondary battery is easy to be unstable in the circulating process when the composite solid electrolyte works at high temperature, and finally, the problems of battery short circuit and the like are caused.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a high-temperature solid electrolyte, a method for preparing the same, and an application of the same, wherein the high-temperature solid electrolyte provided by the present invention has high thermal stability and structural stability, and an ion battery prepared from the high-temperature solid electrolyte provided by the present invention has high ionic conductivity and high cycling stability.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a high-temperature solid electrolyte, which comprises a bacterial cellulose membrane, silicon dioxide nanoparticles and an ionic liquid electrolyte; the bacterial cellulose membrane is provided with a three-dimensional network structure, and the silica nanoparticles and the ionic liquid electrolyte are distributed inside the three-dimensional network structure of the bacterial cellulose membrane; the ionic liquid electrolyte is coated on the surface of the silica nanoparticle.

Preferably, the ionic liquid electrolyte is a mixed solution of an organic lithium salt and an ionic liquid; the molar concentration of the organic lithium salt in the ionic liquid electrolyte is 0.5-1.5 mol/L; the molar ratio of the ionic liquid to the silicon dioxide nanoparticles is 0.5-2: 1; the average particle size of the silicon dioxide nanoparticles is 10-50 nm.

Preferably, the organic lithium salt comprises one or more of lithium bistrifluoromethanesulfonylimide, lithium bisfluorosulfonylimide, lithium perfluoroethanesulfonyl imide and lithium perfluoromethanesulfonyl methide.

Preferably, the ionic liquid comprises N-methyl, propyl pyrrolidine bis (trifluoromethanesulfonimide) salt, N-methyl, butyl pyrrolidine bis (trifluoromethanesulfonimide) salt, N-methyl, propyl pyrrolidine bis (fluoromethanesulfonylimide) salt, N-methyl, propyl piperidine bis (trifluoromethanesulfonimide) salt, N-methyl, butyl piperidine bis (trifluoromethanesulfonimide) salt, N-methyl, propyl piperidine bis (fluoromethanesulfonylimide) salt, 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonimide) salt, 1-propyl-3-methylimidazole bis (trifluoromethanesulfonimide) salt, 1-butyl-3-methylimidazole bis (trifluoromethanesulfonimide) salt, 1-ethyl-3-methylimidazole bis (fluoromethanesulfonylimide) salt, 1-propyl-3-methylimidazole bis (fluoromethanesulfonylimide) salt and 1-butyl-3-methylimidazole bis (trifluoromethanesulfonimide) salt One or more of bis-fluoromethanesulfonylimide salts.

Preferably, the silicon dioxide nanoparticles are generated by hydrolyzing silicate organic matters through an in-situ sol-gel reaction.

Preferably, the silicate organic matter comprises one or more of methyl silicate, ethyl silicate, propyl silicate, isopropyl silicate and butyl silicate.

The invention provides a preparation method of the high-temperature solid electrolyte, which comprises the following steps:

carrying out first mixing on an organic lithium salt and an ionic liquid to obtain an ionic liquid-organic lithium salt solution;

carrying out second mixing on the ionic liquid-organic lithium salt solution and the silicate organic matter to obtain a mixed solution;

dipping the bacterial cellulose membrane into the mixed solution to obtain a dipped bacterial cellulose membrane;

and dropwise adding formic acid into the bacterial cellulose impregnated membrane, standing and solidifying to obtain the high-temperature solid electrolyte.

Preferably, the first mixing and the second mixing are independently carried out under the condition of stirring, and the stirring speed is independently 300-500 r/min; the stirring time is independently 3-10 min.

Preferably, the dipping time is 12-48 h; the standing and curing time is 4-7 days; the temperature of standing and curing is 70-100 ℃.

The invention provides the application of the high-temperature solid electrolyte in the technical scheme or the high-temperature solid electrolyte obtained by the preparation method in the technical scheme in a lithium battery.

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

the invention provides a high-temperature solid electrolyte which can exert the respective advantages of all components and has excellent comprehensive performance: the system has high thermal stability and dimensional stability in a macroscopic view, and the ionic liquid in the system is uniformly coated on the outer surface of the nano particles on a microscopic structure to form a continuous liquid phase so as to provide a rapid channel for the migration and conduction of ions. The results of the embodiment show that the high-temperature solid electrolyte provided by the invention has excellent high thermal stability and structural stability, and has good thermal stability and cycling stability when being made into a lithium battery and working in a high-temperature environment, the first-cycle discharge specific capacity is 158.6-163.4 mAh/g, the discharge specific capacity after 10-cycle is 157.8-161.8 mAh/g, and the coulombic efficiency is 96.0-99.9%.

The invention provides a preparation method of a high-temperature solid electrolyte, wherein the high-temperature solid electrolyte adopts an in-situ sol-gel method to uniformly compound a bacterial cellulose membrane, an ionic liquid electrolyte and silicon oxide nanoparticles, so that the ionic liquid is uniformly dispersed into a three-dimensional fiber network of the bacterial cellulose membrane in a solid state form integrated with the nanoparticles; the preparation method is simple to operate, green and environment-friendly, and easy to realize large-scale production.

The invention also provides the application of the high-temperature solid electrolyte in the technical scheme or the high-temperature solid electrolyte obtained by the preparation method in the technical scheme in a lithium battery. When the high-temperature solid electrolyte provided by the invention is used for preparing a lithium battery, particularly when the lithium battery is a lithium metal battery, the metal lithium cathode has good interface contact with the high-temperature solid electrolyte and stable interface, the dendrite is well inhibited, and the lithium battery shows good cycle stability and high safety.

Drawings

FIG. 1 is a digital photograph of a high-temperature type solid electrolyte prepared in example 1 after heat treatment;

FIG. 2 is a scanning electron microscope photograph of the high-temperature type solid electrolyte prepared in example 1 after removing ionic liquid;

fig. 3 is a graph showing cycle performance at 140 c of a lithium metal secondary battery assembled with the high-temperature type solid electrolyte prepared in example 1.

Detailed Description

The invention provides a high-temperature solid electrolyte, which comprises a bacterial cellulose membrane, silicon dioxide nanoparticles and an ionic liquid electrolyte; the bacterial cellulose membrane is provided with a three-dimensional network structure, and the silica nanoparticles and the ionic liquid electrolyte are distributed inside the three-dimensional network structure of the bacterial cellulose membrane; the ionic liquid electrolyte is coated on the surface of the silica nanoparticle.

In the present invention, the ionic liquid electrolyte is preferably a mixed solution of an organic lithium salt and an ionic liquid; the molar concentration of the organic lithium salt in the ionic liquid electrolyte is preferably 0.5-1.5 mol/L, and more preferably 0.8-1.2 mol/L; the mol ratio of the ionic liquid to the silicon dioxide nanoparticles is preferably 0.5-2.0: 1.0, more preferably 1.0 to 1.5: 1.0; the average particle size of the silicon dioxide nanoparticles is preferably 10-50 nm, and more preferably 20-45 nm.

In the invention, the bacterial cellulose membrane is preferably a milky dry membrane, the interior of the bacterial cellulose membrane is provided with a rich hyperfine three-dimensional reticular structure, and the thickness of the bacterial cellulose membrane is preferably 20-100 μm, and is further preferably 25-50 μm; the bacterial cellulose membrane preferably has a diameter of 19 mm. The source of the bacterial cellulose membrane is not specially required, and a commercially available product is adopted, and in the embodiment of the invention, the bacterial cellulose membrane is purchased from Beijing Youlan science and technology Co.

In the present invention, the organic lithium salt preferably includes one or more of lithium bis (trifluoromethanesulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium perfluoroethanesulfonyl imide, and lithium perfluoromethanesulfonyl methide, and further preferably includes lithium trifluoromethanesulfonyl imide, lithium bis (fluorosulfonyl) imide, lithium perfluoroethanesulfonyl imide, or lithium perfluoromethanesulfonyl methide. In the invention, when the organic lithium salt preferably comprises more than two of bis (trifluoromethane sulfonyl) imide lithium, bis (fluorosulfonyl) imide lithium, perfluoroethane sulfonyl imide lithium and perfluoromethane sulfonyl methyl lithium, the mass ratio of the specific substances in the invention has no special requirement, and any ratio can be adopted. The source of the organic lithium salt is not specially required, and a commercial product is adopted.

In the present invention, the ionic liquid preferably includes N-methyl, propyl pyrrolidine bistrifluoromethylsulfonyl imide salt, N-methyl, butyl pyrrolidine bistrifluoromethylsulfonyl imide salt, N-methyl, propyl piperidine bistrifluoromethylsulfonyl imide salt, N-methyl, butyl piperidine bistrifluoromethylsulfonyl imide salt, N-methyl, propyl piperidine bistrifluoromethylsulfonyl imide salt, 1-ethyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-propyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-butyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-ethyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-propyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt and 1-butyl-3- One or more of methylimidazolium bis-fluoromethanesulfonylimide salts, further preferably N-methyl, propylpyrrolidine bis-trifluoromethanesulfonimide salt, N-methyl, butylpyrrolidine bis-trifluoromethanesulfonimide salt, N-methyl, propylpyrrolidine bis-fluoromethanesulfonylimide salt, N-methyl, propylpiperidine bis-trifluoromethanesulfonimide salt, N-methyl, butylpiperidine bis-trifluoromethanesulfonimide salt, N-methyl, propylpiperidine bis-fluoromethanesulfonylimide salt, 1-ethyl-3-methylimidazolium bis-trifluoromethanesulfonimide salt, 1-propyl-3-methylimidazolium bis-trifluoromethanesulfonimide salt, 1-butyl-3-methylimidazolium bis-trifluoromethanesulfonimide salt, 1-ethyl-3-methylimidazolium bis-fluoromethanesulfonylimide salt, N-methyl-pyrrolidine bis-trifluoromethanesulfonimide salt, N, 1-propyl-3-methylimidazolium bis (fluoromethanesulfonylimide) salt or 1-butyl-3-methylimidazolium bis (fluoromethanesulfonylimide) salt; in the present invention, when the ionic liquid preferably comprises N-methyl, propyl pyrrolidine bistrifluoromethylsulfonyl imide salt, N-methyl, butyl pyrrolidine bistrifluoromethylsulfonyl imide salt, N-methyl, propyl piperidine bistrifluoromethylsulfonyl imide salt, N-methyl, butyl piperidine bistrifluoromethylsulfonyl imide salt, N-methyl, propyl piperidine bistrifluoromethylsulfonyl imide salt, 1-ethyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-propyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-butyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-ethyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt, 1-propyl-3-methylimidazole bistrifluoromethylsulfonyl imide salt and 1-butyl-3- When more than two of the methylimidazole bis (fluoromethanesulfonylimide) salts are used, the mass ratio of the specific substances is not particularly required, and any ratio can be adopted. The source of the ionic liquid has no special requirement, and the ionic liquid can be obtained by adopting a commercial product.

In the invention, the silicon dioxide nano-particles are generated by hydrolyzing silicate organic matters through an in-situ sol-gel reaction. In the invention, the silicate organic matter preferably comprises one or more of methyl silicate, ethyl silicate, propyl silicate, isopropyl silicate and butyl silicate, and further preferably comprises methyl silicate, ethyl silicate, propyl silicate, isopropyl silicate or butyl silicate.

The invention provides a preparation method of the high-temperature solid electrolyte, which comprises the following steps:

carrying out first mixing on an organic lithium salt and an ionic liquid to obtain an ionic liquid-organic lithium salt solution;

carrying out second mixing on the ionic liquid-organic lithium salt solution and the silicate organic matter to obtain a mixed solution;

dipping the bacterial cellulose membrane into the mixed solution to obtain a dipped bacterial cellulose membrane;

and dropwise adding formic acid into the bacterial cellulose impregnated membrane, standing and solidifying to obtain the high-temperature solid electrolyte.

In the present invention, all the raw material components are commercially available products of swine to those skilled in the art, unless otherwise specified.

The method for preparing the high-temperature solid electrolyte is preferably performed in an environment filled with an inert gas, preferably argon, and having a moisture content of 0.1ppm or less, and in the embodiment of the present invention, the method is preferably performed in a glove box filled with an inert gas, preferably having a moisture content of 0.1ppm or less.

According to the invention, organic lithium salt and ionic liquid are subjected to first mixing to obtain ionic liquid-organic lithium salt solution.

In the invention, the first mixing is preferably carried out under the condition of stirring, and the stirring speed is preferably 300-500 r/min, and more preferably 400-450 r/min; the stirring time is preferably 3-10 min, more preferably 6-8 min, and the stirring is preferably mechanical stirring. In the invention, the molar concentration of the organic lithium salt in the ionic liquid-organic lithium salt solution is preferably 0.5-1.5 mol/L, and more preferably 0.8-1.2 mol/L.

Obtaining an ionic liquid-organic lithium salt solution; the ionic liquid-organic lithium salt solution and the silicate organic matter are subjected to second mixing to obtain a mixed solution.

In the invention, the second mixing is preferably carried out under the condition of stirring, and the stirring speed is preferably 300-500 r/min, and more preferably 350-450 r/min; the stirring time is preferably 3-10 min, more preferably 4-7 min, and the stirring time is preferably mechanical stirring; in the invention, the molar ratio of the ionic liquid to the silicate organic matter in the ionic liquid-organic lithium salt solution is preferably 0.5-2: 1, more preferably 1.0 to 1.5: 1.

after the mixed solution is obtained, the bacterial cellulose membrane is soaked in the mixed solution to obtain the soaked bacterial cellulose membrane.

In the invention, the bacterial cellulose membrane is preferably dried and then soaked, and the drying process is not particularly required, and the operation process well known to the skilled person can be adopted. The invention removes the moisture of the bacterial cellulose membrane through drying treatment.

In the present invention, the time for the immersion is preferably 12 to 48 hours, and more preferably 24 to 36 hours. The present invention does not require any particular operation for the impregnation, and can be carried out by operations known to those skilled in the art.

After the impregnated bacterial cellulose membrane is obtained, formic acid is dripped into the impregnated bacterial cellulose membrane, and the impregnated bacterial cellulose membrane is kept stand and solidified to obtain the high-temperature solid electrolyte.

The dropping speed of the formic acid to the impregnated bacterial cellulose membrane has no special requirement. In the invention, the standing and curing time is preferably 4-7 days, and more preferably 5-6 days; the temperature of standing and curing is preferably 70-100 ℃.

In the invention, in the standing and curing process, silicate organic matters in the impregnated bacterial cellulose membrane are subjected to sol-gel reaction under the action of formic acid to generate silicon dioxide nanoparticles, wherein the average particle size of the silicon dioxide nanoparticles is 10-50 nm, and more preferably 20-45 nm.

According to the preparation method provided by the invention, the bacterial cellulose membrane, the ionic liquid electrolyte and the silicon dioxide nanoparticles are uniformly compounded by adopting an in-situ sol-gel method, so that the ionic liquid electrolyte and the silicon dioxide nanoparticles are uniformly dispersed into a three-dimensional fiber network of the bacterial cellulose membrane in an integrated solid state form; the preparation method is simple to operate, green and environment-friendly, and easy to realize large-scale production.

The invention also provides the application of the high-temperature solid electrolyte in the technical scheme or the high-temperature solid electrolyte prepared by the preparation method in the technical scheme in a lithium battery.

The invention has no special requirements on the specific method for applying the high-temperature solid electrolyte in the lithium battery, and the application method of the solid electrolyte in the lithium battery, which is well known to the technical personnel in the field, can be adopted.

When the high-temperature solid electrolyte provided by the invention is applied to a lithium metal battery, the interface contact between a lithium metal cathode and the high-temperature solid electrolyte is good, the interface is stable, the dendrite is well inhibited, and the lithium metal battery shows good cycling stability and high safety.

In an embodiment of the present invention, a specific method of application of the high temperature type solid electrolyte in a lithium battery includes the steps of:

active electrode material LiFePO₄Premixing acetylene black and polyvinylidene fluoride to obtain a mixed electrode material;

preliminarily mixing the mixed electrode material and N-methyl pyrrolidone, and grinding to obtain electrode slurry;

coating the electrode slurry on an Al foil, and sequentially drying, rolling and punching to obtain an electrode slice;

and sequentially placing the electrode plate, the high-temperature solid electrolyte and the metal lithium sheet into the button battery shell, and tabletting to obtain the lithium metal secondary battery.

The invention uses active electrode material LiFePO₄And premixing the acetylene black and the polyvinylidene fluoride to obtain the mixed electrode material.

In the present invention, the active electrode material LiFePO₄The mass ratio of acetylene black to polyvinylidene fluoride is preferably 8: 1: the invention has no special requirements on the specific operation method of the premixing, and the specific operation of the mixing which is well known to the technical personnel in the field is adopted to realize the uniform mixing.

Obtaining a mixed electrode material; preliminarily mixing the mixed electrode material and N-methyl pyrrolidone, and grinding to obtain electrode slurry;

the invention has no special requirements on the specific operation method of the preliminary mixing, and the specific operation of mixing which is well known by the technical personnel in the field is adopted to realize uniform mixing. The method for the grinding operation is not particularly required, and the grinding operation known to those skilled in the art can be used.

After obtaining the electrode slurry, coating the electrode slurry on an Al foil, and sequentially drying, rolling and punching to obtain an electrode slice;

the invention has no special requirements on the coating mode, and the coating mode known by the technicians in the field can be adopted; in the present invention, the diameter of the Al foil is preferably 11mm, and the source of the Al foil is not particularly limited in the present invention, and a commercially available product may be used. In the present invention, the drying temperature is preferably 80 ℃, the drying time is preferably 24h, the drying is preferably vacuum drying, and the drying equipment is preferably a vacuum drying oven. The invention has no special requirement on the specific method of rolling and punching, and the method of rolling and punching, which is well known to those skilled in the art, can be adopted, and in the invention, the thickness of the electrode plate is preferably 150 μm, and the diameter is preferably 11 mm.

After the electrode plate is obtained, the electrode plate, the high-temperature solid electrolyte and the metal lithium sheet are sequentially placed into a button battery shell, and the lithium metal secondary battery is obtained through tabletting.

In the invention, the electrode plate, the high-temperature solid electrolyte and the metal lithium sheet are sequentially placed in a button battery case, the tabletting process is preferably carried out in a glove box filled with argon, the type of the button battery case is preferably 2025, the invention has no special requirement on the specific tabletting method, and the tabletting method known to a person skilled in the art can be adopted.

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.