阅读说明：本技术 一种固体电解质界面膜及其制备方法 (Solid electrolyte interface film and preparation method thereof ) 是由 易陈谊 张宇 刘越 周俊杰 谭理国 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种固体电解质界面膜的制备方法,包括,在锂金属表面采用钙钛矿形成所述固体电解质界面膜。其中,所述钙钛矿选自KNiF-(3)、KMnF-(3)、KCuF-(3)、KZnF-(3)、KCoF-(3)、KNiCl-(3)、KMnCl-(3)、KCuCl-(3)、KZnCl-(3)或KCoCl-(3)中的至少一种,所述固体电解质界面膜的厚度为1-5000nm,所述锂金属表面采用钙钛矿材料形成所述固体电解质界面膜的方法选自溶液旋涂法、溶液刮涂、狭缝挤压涂布、溶液喷涂、溶液丝网印刷、或真空蒸镀法中的至少一种。本发明的方法制得的固体电解质界面膜,其钙钛矿组成材料和结构十分稳定,在高温、湿度和化学试剂中具有良好的稳定性,不会出现钙钛矿分解或者相变等问题。(The invention discloses a preparation method of a solid electrolyte interface film, which comprises the step of forming the solid electrolyte interface film on the surface of lithium metal by adopting perovskite. Wherein the perovskite is selected from KNiF 3 、KMnF 3 、KCuF 3 、KZnF 3 、KCoF 3 、KNiCl 3 、KMnCl 3 、KCuCl 3 、KZnCl 3 Or KCoCl 3 Wherein the thickness of the solid electrolyte interface film is 1-5000nm, and the method for forming the solid electrolyte interface film by adopting the perovskite material on the surface of the lithium metal is at least one selected from a solution spin coating method, a solution blade coating method, a slit extrusion coating method, a solution spraying method, a solution screen printing method and a vacuum evaporation method. The solid electrolyte interface film prepared by the method of the invention has perovskite composition materials and structureStable, has good stability in high temperature, humidity and chemical reagents, and does not have the problems of perovskite decomposition or phase change and the like.)

1. A method for producing a solid electrolyte interface film, comprising forming the solid electrolyte interface film on a lithium metal surface by using perovskite.

2. The method of producing a solid electrolyte interface film as claimed in claim 1 wherein the perovskite is selected from KNiF₃、KMnF₃、KCuF₃、KZnF₃、KCoF₃、KNiCl₃、KMnCl₃、KCuCl₃、KZnCl₃Or KCoCl₃At least one of (1).

3. The method of producing a solid electrolyte interface film as claimed in claim 2 wherein the perovskite is selected from KNiF₃、KMnF₃、KCuF₃、KZnF₃、KCoF₃At least one of (1).

4. The solid electrolyte interface film as claimed in claim 3 wherein the perovskite material is prepared by adding a methanolic solution of potassium fluoride to a methanolic solution of nickel chloride, manganese chloride, copper chloride, zinc chloride or cobalt chloride to form a solid product, filtering, washing and drying to obtain KNiF₃、KMnF₃、KCuF₃、KZnF₃Or KCoF₃And (3) powder.

5. The method of producing a solid electrolyte interface film according to claim 1 wherein the thickness of the solid electrolyte interface film is 1 to 5000 nm.

6. The method of producing a solid electrolyte interface film according to claim 1 wherein the method of forming the solid electrolyte interface film on the lithium metal surface using a perovskite material is at least one selected from the group consisting of solution spin coating, solution blade coating, slit extrusion coating, solution spray coating, solution screen printing, and vacuum evaporation.

7. The method for preparing a solid electrolyte interface film according to claim 1 wherein the solution spin coating comprises dissolving the perovskite in a solvent, dropping a solution containing the perovskite on the metallic lithium plate, wherein the solvent is at least one selected from the group consisting of N, N-dimethylformamide, dimethylsulfoxide, γ -butyrolactone, chlorobenzene, and N-hexane, the concentration of the solution containing the perovskite is 1-1500mg/ml, spin coating is performed by a spin coater at a spin speed of 1000-.

8. A solid electrolyte interface film, characterized in that it is produced by the method according to any one of claims 1 to 7.

9. A lithium electrode comprising the solid electrolyte interface film of claim 8.

10. A lithium battery comprising the lithium electrode of claim 9.

Technical Field

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a solid electrolyte interface film, and a preparation method of the solid electrolyte interface film.

Background

Along with the popularization of electronic products and electric automobiles, the specific capacity of the graphite cathode of the commercial lithium ion battery gradually approaches to the theoretical limit value (372 mAh.g)^-1) It is difficult to satisfy the increasing social demands. Metallic lithium is a metal having the smallest density in nature (0.534g cm)^-3) Has extremely high theoretical specific capacity (3860mAh g)^-1) Lowest electrode potential (-3.04V vs standard hydrogen electrode) and good mechanical flexibility. These advantages have facilitated the replacement of graphite by metallic lithium as the battery negative electrode. Representative lithium-sulfur and lithium-air batteries are expected to become the next generation of high energy density batteries. However, lithium metal has high reactivity and is easily subjected to side reactions with the electrolyte. In the reaction, the uneven dissolution and deposition of lithium are easy to generate dendritic crystals, and the lithium dendritic crystals can pierce a battery diaphragm to cause short circuit of a positive electrode and a negative electrode in the battery, so that safety accidents such as gas expansion, thermal runaway and even combustion explosion are caused.

Therefore, it is necessary to take effective measures to protect the lithium metal negative electrode, so as to inhibit the growth of lithium dendrites and improve the safety of the lithium metal battery.

Disclosure of Invention

The present invention is based on the discovery and recognition by the inventors of the following facts and problems: the construction of Solid Electrolyte Interface (SEI) films is a common lithium metal protection method, and SEI materials mainly include inorganic compounds, polymers, organic/inorganic composites, and the like. Common inorganic SEI films are LiF and Li₃N、Li₂S and other lithium-containing compounds, which generally have high lithium ion transport rate and electrolyte barrier properties, but are large in rigidity, insufficient in flexibility, and difficult to withstand volume changes caused by long-term cycling of lithium metal; the polymer SEI film generally has high Young modulus (0.4-4.83 GPa) and good stability, and can bear severe deformation of lithium metal so as to inhibit the growth of lithium dendrites. But the electron and ion conductivity of the polymer material are poor, which is not favorable for the efficient transmission of charges in the charging and discharging process; organic/inorganic composite SEI film combinedOrganic compounds and organic polymers, but the SEI film has a complex preparation process and is easy to generate side reaction with electrolyte during charging and discharging to damage a composite structure. Therefore, the development of a chemically stable SEI film material that has high lithium ion transport performance and can inhibit lithium dendrite volume expansion is a key to solving the safety problem of lithium metal negative electrodes.

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the embodiment of the invention provides a solid electrolyte interface film and a preparation method thereof, and the prepared solid electrolyte interface film has stable composition materials and structure, good stability in high temperature, humidity and chemical reagents, and no problems of perovskite decomposition or phase change and the like.

The method for producing a solid electrolyte interface film according to an embodiment of the present invention includes forming the solid electrolyte interface film on a lithium metal surface using perovskite.

According to the advantages and technical effects of the preparation method of the solid electrolyte interface film provided by the embodiment of the invention, 1, in the embodiment of the invention, a perovskite material is used as a solid electrolyte interface of lithium metal, a uniform and stable protective layer is formed on the surface of the lithium metal, the composition and structure of perovskite on the protective layer are stable, the protective layer has good temperature and chemical stability, the protective layer has good stability in high temperature, high humidity and chemical reagents, and the problems of perovskite decomposition or phase change and the like can not occur; 2. in the embodiment of the invention, the perovskite protective film is modified on the surface of the lithium metal, so that the electrolyte and the lithium metal can be effectively isolated, the occurrence of side reaction is inhibited to a certain extent, and the growth of lithium dendrite is slowed down; 3. the solid electrolyte interface prepared by the method provided by the embodiment of the invention can improve the interface between lithium metal and electrolyte, effectively reduce the interface resistance and is beneficial to the transmission of lithium ions; 4. in the embodiment of the invention, the adopted perovskite material has a regular octahedral structure, so that spontaneous migration of lithium ions in the structure is ensured, the lithium ions are induced to be uniformly deposited on the metal electrode, the growth of lithium dendrites is effectively inhibited, and a good protection effect on a metal lithium cathode can be achieved in a long-cycle process.

In some embodiments, the perovskite is selected from KNiF₃、KMnF₃、KCuF₃、KZnF₃、KCoF₃、KNiCl₃、KMnCl₃、KCuCl₃、KZnCl₃Or KCoCl₃At least one of (1).

In some embodiments, the perovskite is selected from KNiF₃、KMnF₃、KCuF₃、KZnF₃、KCoF₃At least one of (1).

In some embodiments, the perovskite material is prepared by adding a methanolic solution of potassium fluoride to a methanolic solution of nickel chloride, manganese chloride, copper chloride, zinc chloride, or cobalt chloride to produce a solid product, filtering, washing, and drying to obtain KNiF₃、KMnF₃、KCuF₃、KZnF₃Or KCoF₃And (3) powder.

In some embodiments, the solid electrolyte interface film has a thickness of 1 to 5000 nm.

In some embodiments, the method of forming the solid electrolyte interface film using a perovskite material on the lithium metal surface is selected from at least one of a solution spin coating method, a solution blade coating method, a slit extrusion coating method, a solution spray coating method, a solution screen printing method, and a vacuum evaporation method.

In some embodiments, the solution spin coating method comprises dissolving perovskite in a solvent, dropping a solution containing perovskite on a metal lithium sheet, wherein the solvent is at least one selected from N, N-dimethylformamide, dimethyl sulfoxide, gamma-butyrolactone, chlorobenzene or N-hexane, the concentration of the solution containing perovskite is 1-1500mg/ml, spin coating is performed by using a spin coater at a spin coating speed of 1000-8000rmp for 10-100s, and heat treatment is performed after the spin coating is finished, the heat treatment temperature is 40-150 ℃, and the heat treatment time is 2-20min, so as to obtain the solid electrolyte interface film.

The embodiment of the invention also provides a solid electrolyte interface film which is prepared by the preparation method of the embodiment of the invention.

According to the advantages and the technical effects of the solid electrolyte interface film disclosed by the embodiment of the invention, 1, a layer of perovskite protective film is modified on the surface of lithium metal, the perovskite solid electrolyte interface is stable in composition material and structure, has good stability in high temperature, humidity and chemical reagents, cannot cause the problems of perovskite decomposition or phase change and the like, can effectively isolate electrolyte from the lithium metal, effectively inhibits the occurrence of side reactions, and slows down the growth of lithium dendrites; 2. in the embodiment of the invention, the special octahedral structure of the perovskite material can ensure spontaneous de-intercalation of lithium ions, and a favorable channel is provided for transmission of the lithium ions in the charge and discharge processes; 3. the solid electrolyte interface film disclosed by the embodiment of the invention is simple in preparation method and easy to apply, and can be used as a lithium cathode protective film.

The embodiment of the invention also provides a lithium electrode which comprises the solid electrolyte interface film.

The lithium electrode in the embodiment of the present invention includes the solid electrolyte interface film prepared in the embodiment of the present invention, and has all the advantages that the solid electrolyte interface film in the embodiment of the present invention can bring, and details are not described herein again.

The embodiment of the invention also provides a lithium battery which comprises the lithium electrode provided by the embodiment of the invention.

The lithium battery provided by the embodiment of the invention comprises the lithium electrode provided by the embodiment of the invention, can still maintain higher capacity after long-time charge and discharge cycles, has excellent charge and discharge capacity and cycle performance, can be applied to a high-specific energy electricity cyclic energy storage device, has all the advantages brought by the lithium electrode provided by the embodiment of the invention, and is not repeated herein.

Drawings

FIG. 1 is a schematic view of a process for producing a solid electrolyte interface film according to an embodiment of the present invention;

FIG. 2 is a graph comparing the results of the charge and discharge tests of the symmetrical batteries of example 1 of the present invention and comparative example 1;

fig. 3 is a comparison graph of the surface and cross-sectional morphology of a lithium electrode obtained by circularly disassembling a battery prepared in example 1 and a battery prepared in comparative example 1, wherein a and c are graphs of the surface and cross-sectional morphology of the lithium electrode obtained by circularly disassembling the battery in comparative example 1, and b and d are graphs of the surface and cross-sectional morphology of the lithium electrode obtained by circularly disassembling the battery in example 1;

fig. 4 is a comparison graph of the charge-discharge cycle performance and the rate performance of lithium iron phosphate full batteries according to example 2 and comparative example 2, wherein a is a charge-discharge cycle performance test graph, and b is a rate performance test graph.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1, the method for producing a solid electrolyte interface film according to an embodiment of the present invention includes forming the solid electrolyte interface film on a lithium metal surface using perovskite, and preferably, the thickness of the solid electrolyte interface film is 1 to 5000nm, and more preferably, 50 to 500 nm.

According to the preparation method of the solid electrolyte interface film provided by the embodiment of the invention, the perovskite material is used as the solid electrolyte interface of the lithium metal, a uniform and stable protective layer is formed on the surface of the lithium metal, the composition and the structure of the perovskite on the protective layer are stable, the perovskite has good temperature and chemical stability, the perovskite has good stability in high temperature, high humidity and chemical reagents, and the problems of decomposition or phase change of the perovskite and the like can be avoided; in the embodiment of the invention, the perovskite protective film is modified on the surface of the lithium metal, so that the electrolyte and the lithium metal can be effectively isolated, the occurrence of side reaction is inhibited to a certain extent, and the growth of lithium dendrite is slowed down; the solid electrolyte interface prepared by the method provided by the embodiment of the invention can improve the interface between lithium metal and electrolyte, effectively reduce the interface resistance and is beneficial to the transmission of lithium ions; in the embodiment of the invention, the adopted perovskite material has a regular octahedral structure, so that spontaneous migration of lithium ions in the structure is ensured, the lithium ions are induced to be uniformly deposited on the metal electrode, the growth of lithium dendrites is effectively inhibited, and a good protection effect on a metal lithium cathode can be achieved in a long-cycle process.

In some embodimentsWherein the perovskite is selected from KNiF₃、KMnF₃、KCuF₃、KZnF₃、KCoF₃、KNiCl₃、KMnCl₃、KCuCl₃、KZnCl₃Or KCoCl₃Preferably the perovskite is selected from KNiF₃、KMnF₃、KCuF₃、KZnF₃、KCoF₃At least one of (1). Preferably, the preparation method of the perovskite material comprises the steps of adding a methanol solution of potassium fluoride into a methanol solution of nickel chloride, manganese chloride, copper chloride, zinc chloride or cobalt chloride to generate a solid product, filtering, cleaning and drying to obtain KNiF₃、KMnF₃、KCuF₃、KZnF₃Or KCoF₃And (3) powder. The perovskite material provided by the embodiment of the invention can form a stable structure on the surface of lithium metal, the temperature and chemical stability are excellent, meanwhile, the octahedral structure of the perovskite material effectively ensures the spontaneous migration of lithium ions in the structure of the perovskite material, and the growth of lithium dendrites is inhibited.

In some embodiments, the method of forming the solid electrolyte interface film using a perovskite material on the lithium metal surface is selected from at least one of a solution spin coating method, a solution blade coating method, a slit extrusion coating method, a solution spray coating method, a solution screen printing method, and a vacuum evaporation method. Preferably, the solution spin coating method comprises the steps of dissolving perovskite in a solvent, dripping a solution containing perovskite on a metal lithium sheet, wherein the solvent is at least one selected from N, N-dimethylformamide, dimethyl sulfoxide, gamma-butyrolactone, chlorobenzene or N-hexane, the concentration of the solution containing perovskite is 1-1500mg/ml, preferably 5-50mg/ml, spin coating is carried out by adopting a spin coater, the spin coating speed is 1000-8000rpm, preferably 2000-4000rpm, the spin coating time is 10-100s, preferably 20-40s, heat treatment is carried out after the spin coating is finished, the heat treatment temperature is 40-150 ℃, preferably 60-100 ℃, the heat treatment time is 2-20min, preferably 5-10min, and the solid electrolyte interface membrane is prepared. The method provided by the embodiment of the invention is simple in preparation method, green and environment-friendly, and easy to apply.

The embodiment of the invention also provides a solid electrolyte interface film which is prepared by the preparation method of the embodiment of the invention.

According to the solid electrolyte interface film provided by the embodiment of the invention, the perovskite protective film is modified on the surface of lithium metal, the perovskite solid electrolyte interface composition material and structure are very stable, the film has good stability in high temperature, humidity and chemical reagents, the problems of perovskite decomposition or phase change and the like can not occur, the electrolyte and the lithium metal can be effectively isolated, the occurrence of side reactions is effectively inhibited, and the growth of lithium dendrites is slowed down; in the embodiment of the invention, the special octahedral structure of the perovskite material can ensure spontaneous de-intercalation of lithium ions, and a favorable channel is provided for transmission of the lithium ions in the charge and discharge processes; the solid electrolyte interface film disclosed by the embodiment of the invention is simple in preparation method and easy to apply, and can be used as a lithium cathode protective film.

The embodiment of the invention also provides a lithium electrode which comprises the solid electrolyte interface film. The lithium electrode of the embodiment of the invention has all the advantages brought by the solid electrolyte interface film of the embodiment of the invention, and details are not described herein.

The embodiment of the invention also provides a lithium battery which comprises the lithium electrode provided by the embodiment of the invention. The lithium battery provided by the embodiment of the invention comprises a negative electrode, a positive electrode, a diaphragm, electrolyte, a current collector and the like. The lithium electrode provided by the embodiment of the invention can be adopted as the anode and the cathode according to the requirement; septa include, but are not limited to, Celgard 2400, Celgard 2325, Celgard 2500, and the like; electrolytes include, but are not limited to, 1.0M 1, 3-dioxolane/glyme (DOL/DME v: v 1:1) solution of lithium bistrifluoromethane sulfonimide (LiTFSI), 1.0M lithium hexafluorophosphate (LiPF)₆) And ethylene carbonate/diethyl carbonate (EC/DEC v: v 1:1) solution.

The lithium battery provided by the embodiment of the invention can still maintain higher capacity after long-time charge and discharge cycles, has excellent charge and discharge capacity and cycle performance, can be applied to a high-specific-energy electrical cycle energy storage device, has all the advantages brought by the lithium electrode provided by the embodiment of the invention, and is not repeated herein.

The present invention will be described in detail below with reference to examples and the accompanying drawings.

In the following examples, a newway test system is adopted for battery performance tests, Celgard 2400 is used as a diaphragm, a 1, 3-dioxolane/glyme (DOL/DME, volume ratio of 1:1) mixed solution with concentration of 1.0M bis (trifluoromethane) sulfonimide Lithium (LiTFSI) is selected as the electrolyte of the symmetric battery in example 1, and lithium iron phosphate (LFP) lithium metal battery in example 3 is selected as the electrolyte of the lithium hexafluorophosphate (LiPF) with concentration of 1.0M₆) Commercial electrolyte (koledo), perovskite solid electrolyte interface of lithium metal was prepared in an argon glove box (water content < 0.1ppm, oxygen content < 0.1ppm) and CR2032 coin cells were assembled.

EXAMPLE 1 preparation of lithium Metal symmetrical Battery

(1) Adding potassium fluoride (KF) methanol solution according to a molar ratio of 3: 1 to copper chloride (CuCl)₂) Generating a solid product in a methanol solution, filtering the solid product, sequentially cleaning the solid product by using ethanol and acetone, and drying the solid product in an oven at 70 ℃ for 12 hours in vacuum to obtain pure KCuF₃Powder, put in argon glove box for standby.

(2) The obtained KCuF₃The powder is dissolved in DMF solvent after being ground to prepare KCuF with the concentration of 15mg/ml₃DMF solution. Dripping the solution on a metal lithium sheet, rotating at 3000rpm for 30s, heating at 80 deg.C for 10min, and taking off to obtain KCuF with perovskite structure₃A lithium metal sheet of a solid electrolyte interface film.

(3) Two pieces having perovskite KCuF₃And respectively taking the metal lithium sheet of the solid electrolyte interface film as a positive pole piece and a negative pole piece, adding 1.0M of DOL/DME electrolyte into the positive pole piece and the negative pole piece, assembling the metal lithium symmetrical battery, and performing performance test.

Comparative example 1

The same two original lithium sheets (not spin-coated to form perovskite KCuF) as in step (2) of example 1 were used₃Solid electrolyte interface film) as a negative electrode and a positive electrode, and an electrolyte and a separator were assembled into a lithium metal symmetrical battery in the same manner as in example 1, and the process was carried outAnd (5) testing the performance.

The lithium symmetrical batteries obtained in example 1 and comparative example 1 were subjected to charge-discharge cycle tests under the same conditions, respectively, and the charge-discharge conditions of the batteries were set to 4 mA-cm^-2And 4mAh · cm^-2. As shown in fig. 2, the lithium symmetric battery prepared in example 1 maintained an overpotential of about 0.12V after a long cycle time of 3000 hours. While the overpotential of the lithium symmetrical battery manufactured in comparative example 1 gradually increased after 400 hours and reached 0.35V at 1600 hours. A comparison of the cycling curves for the symmetric cells of example 1 and comparative example 1 shows that the cycling performance of the lithium negative electrode prepared in example 1 is significantly better than the original lithium negative electrode of comparative example 1.

The lithium metal electrodes prepared in example 1 and comparative example 1 were observed for morphology after cycling: the lithium symmetrical batteries prepared in example 1 and comparative example 1 were each charged at 4mA · cm^-2And 4mAh · cm^-2After 100 cycles of charge and discharge under the conditions, the product was disassembled in a glove box. The resulting lithium metal electrode was rinsed with DOL solvent and dried in vacuum in a transition chamber to remove the solvent. The morphology of the metal lithium electrode after cycling was observed by SEM, as seen in comparison of fig. 3, fig. 3a and 3c for the metal lithium electrode made in comparative example 1, which had uneven black pile on its surface, which is "dead lithium" produced by uneven deposition during cycling. And fig. 3b and 3d are the metal lithium electrode prepared in example 1, and SEM surface and cross-section comparison shows that the surface of the lithium metal prepared in example 1 is uniform and flat, while uneven surface is caused by uneven deposition of lithium ions on the lithium metal electrode of the battery prepared in comparative example 1, and a loose structure is formed by a large amount of stacked dendrites, which seriously affects the deintercalation capability of lithium ions.

Example 2 preparation of lithium iron phosphate all-cell

(1) Adding potassium fluoride (KF) methanol solution according to a molar ratio of 3: 1 to nickel chloride (NiCl)₂) Generating a solid product in a methanol solution, filtering the solid product, sequentially cleaning the solid product by using ethanol and acetone, and drying the solid product in an oven at 70 ℃ for 12 hours in vacuum to obtain pure KNiF₃Powder, put in argon glove box for standby.

(2) The obtained KNiF₃After grinding the powderDissolving in DMF solvent to obtain KNiF 15mg/ml₃DMF solution. The solution was dropped on a lithium metal plate and rotated at 3000rpm for 30 seconds. Heating at 80 deg.C for 10min, and taking off to obtain perovskite KNiF₃A lithium metal sheet of a solid electrolyte interface film.

(3) Commercial lithium iron phosphate (LiFePO)₄LFP), conductive carbon black and polyvinylidene fluoride (PVDF) are mixed in NMP according to the mass ratio of 8:1:1 to form slurry, and the slurry is coated on the surface of an aluminum current collector and dried to obtain the LFP positive electrode. The loading capacity of the LFP anode is 1.5mg/cm². The perovskite KNiF prepared in the step 2₃And (3) taking the metal lithium sheet of the solid electrolyte interface film as a negative electrode, and adding an electrolyte to assemble the battery. The electrolyte of the battery is commercial 1.0M LiPF₆Ethylene carbonate/diethyl carbonate (EC/DEC) solution, with a volume ratio of EC to DEC of 1: 1.

Comparative example 2

The same original metallic lithium piece (not spin-coated to form perovskite KNiF) as in step (2) of example 2 was used₃Solid electrolyte interface film) as a negative electrode, the same LFP pole piece as in example 2 as a positive electrode, and the same electrolyte and separator as in example 2 were assembled into a battery.

The battery obtained in example 2 and the battery obtained in comparative example 2, i.e., the full battery composed of the lithium metal negative electrode and the lithium iron phosphate positive electrode were subjected to a charge-discharge cycle test, and the current rate for charge and discharge was 1C (1C ═ 170mAh · g)^-1)。

The battery obtained in example 2 and the battery obtained in comparative example 2 were subjected to a rate performance test, and the current rates for charge and discharge were 0.2C, 0.5C, 1C, 2C, 3C, 4C, 5C, 6C, 7C, 8C, and 0.2C. The charge cut-off voltage was 4.2V and the discharge cut-off voltage was 2.5V, and the cell was activated before cycling.

As shown in fig. 4a, the initial capacity of the battery prepared in example 2 was slightly higher than that of the battery prepared in comparative example 2. The capacity of the battery prepared in comparative example 2 began to drop significantly after 100 cycles of charge and discharge, while the battery of example 2, due to the effective protection of the lithium negative electrode by the perovskite solid electrolyte interface, could maintain more than 80% of the initial capacity after 400 cycles, and its coulombic efficiency was also significantly higher than the battery of comparative example 2.

As shown in fig. 4b, when a charge and discharge test is performed at different current multiplying powers, the capacity of the battery prepared in example 2 protected by the perovskite layer is always higher than that of the battery prepared in comparative example 2, and it can be seen that the perovskite solid electrolyte interface can induce uniform deposition of lithium ions, inhibit side reactions of the electrode and the electrolyte, and effectively protect the lithium metal negative electrode, thereby improving the cycle performance and the multiplying power performance of the battery.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.