A solid-state electrolyte-coated ternary positive electrode material, a preparation method therefor, and use thereof

Abstract

The application relates to the technical field of lithium ion battery positive electrode materials, in particular to a solid-state electrolyte-coated ternary positive electrode material and a preparation method and application thereof. The preparation method of the solid-state electrolyte-coated ternary positive electrode material comprises the following steps: a nickel-cobalt-manganese hydroxide precursor and a lithium source are uniformly mixed according to a stoichiometric ratio of a ternary material to obtain a mixture; the mixture is placed in an oxygen-containing atmosphere to perform first sintering treatment to obtain the ternary material; a LiB3H8 material is obtained; the ternary material and the LiB3H8 material are uniformly mixed and placed in an inert atmosphere to perform second sintering treatment, and the solid-state electrolyte-coated ternary positive electrode material is obtained. The solid-state electrolyte LiB3H8 material is used as a coating layer, the ternary material and the LiB3H8 material are mixed and coated, and then surface coating fusion is performed in an inert atmosphere, so that the diffusion rate of lithium ions between the positive electrode material and the electrolyte is improved, and the cycle retention rate, specific capacity and rate performance of the battery material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery cathode material, in particular to a solid-state electrolyte coated ternary cathode material and a preparation method and application thereof. BACKGROUND

[0002] Compared with liquid batteries, solid-state batteries have the following advantages: 1) higher safety: solid-state electrolyte is not flammable and has better stability and mechanical properties at high temperatures; 2) higher energy density: solid-state electrolyte has a wider electrochemical window, reduces side reactions with electrode materials, and broadens the range of available electrode materials; 3) longer cycle life: solid-state electrolyte is not volatile and there is no leakage problem.

[0003] The cathode materials of the currently commercialized lithium ion batteries mainly use phosphate materials and ternary materials. Among them, the ternary material has the advantages of more lithium ions that can be used for deintercalation, high energy density, good cycle performance, etc. However, the ternary material for solid-state batteries still has the problems of poor compatibility of material interface with solid-state electrolyte and low lithium ion diffusion coefficient, which affects the diffusion rate of lithium ions between the cathode material and the electrolyte, and further affects the cycle retention rate, specific capacity and rate performance of the battery. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defects of the existing ternary material for solid-state batteries, such as poor compatibility of material interface with solid-state electrolyte and low lithium ion diffusion coefficient, which leads to poor cycle retention rate, specific capacity and rate performance of the battery, so as to provide a solid-state electrolyte coated ternary cathode material and a preparation method and application thereof to solve the above problems.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A preparation method of a solid-state electrolyte coated ternary cathode material, comprising: weighing nickel-cobalt-manganese hydroxide precursors and lithium sources according to the stoichiometric ratio of the ternary material to obtain a mixture; placing the mixture in an oxygen-containing atmosphere to perform a first sintering treatment to obtain a ternary material; obtaining a LiB3H8 material; mixing the ternary material and the LiB3H8 material and placing them in an inert atmosphere to perform a second sintering treatment.

[0007] Preferably, the chemical formula of the ternary material is Li a Ni x Co y Mn 1-x-y O2, wherein 1.0≤a≤1.1, 0.5 0.9 Co 0.05 Mn 0.05 O2.

[0008] Preferably, the molar ratio of the ternary material to the LiB3H8 material is 10:(0.2-2.0);

[0009] Preferably, the lithium source comprises lithium hydroxide;

[0010] Preferably, the oxygen-containing atmosphere is oxygen or air.

[0011] Preferably, the temperature of the first sintering treatment is 600-800℃, preferably 700℃;

[0012] Preferably, the holding time of the first sintering treatment is 8-12h, preferably 10h.

[0013] Preferably, the temperature of the second sintering treatment is 400-500℃, preferably 450℃;

[0014] Preferably, the holding time of the second sintering treatment is 4-6h, preferably 5h;

[0015] Preferably, the inert atmosphere is nitrogen or / and argon.

[0016] Preferably, the obtaining process of the LiB3H8 material comprises: adding nano lithium powder into a tetrahydrofuran solution of borane in anhydrous and oxygen-free environment to react to obtain.

[0017] Preferably, the concentration of the tetrahydrofuran solution of borane is 0.5-1.5mol / L, preferably 1mol / L;

[0018] Preferably, the volume of the tetrahydrofuran solution of borane is 15-20L, preferably 15L, based on 5mol of the molar amount of nano lithium powder.

[0019] Preferably, the temperature of the reaction is room temperature;

[0020] Preferably, the time of the reaction is 6-10h, preferably 8h;

[0021] Preferably, the reaction is also stirring at the same time.

[0022] The application also provides a solid-state electrolyte-coated ternary positive material prepared by the above-mentioned preparation method of the solid-state electrolyte-coated ternary material.

[0023] The application also provides a solid-state lithium ion battery comprising the above-mentioned solid-state electrolyte-coated ternary positive material.

[0024] In the application, the room temperature is 20-30℃, preferably 25℃;

[0025] In the present application, after the nano lithium powder is added into the tetrahydrofuran solution of borane to react, filtration is further carried out to remove insoluble substances, and the filtrate is concentrated to remove the solvent, washed, and vacuum concentrated to remove the solvent. Among them, the washing agent used in the washing is toluene.

[0026] The technical scheme of the present application has the following advantages:

[0027] 1. A preparation method of a solid-state electrolyte-coated ternary positive electrode material, comprising: weighing nickel-cobalt-manganese hydroxide precursors and a lithium source according to the stoichiometric ratio of the ternary material to obtain a mixture; placing the mixture in an oxygen-containing atmosphere to perform a first sintering treatment to obtain a ternary material; obtaining a LiB3H8 material; mixing the ternary material and the LiB3H8 material and placing them in an inert atmosphere to perform a second sintering treatment.

[0028] Meanwhile, the synthesis of the ternary material needs to be carried out in an oxidizing atmosphere, while the synthesis of the LiB3H8 material needs to avoid contact with oxygen. Due to the different synthesis atmospheres, it is impossible to perform in-situ coating of the LiB3H8 material during the synthesis of the ternary material, and the synthesis needs to be carried out in steps and then mixed and coated. However, simple mixing and coating may have the problem of insufficient tightness of the solid-state electrolyte and the surface of the ternary positive electrode material, and there may be gaps, so that the lithium ions cannot be stably transmitted, resulting in a still low lithium ion diffusion rate. Based on this, after the ternary material and the LiB3H8 material are mixed and coated, surface coating fusion is performed in an inert atmosphere to improve the ability of lithium ions to be extracted from the surface of the ternary material and enter the solid-state electrolyte. Unlike ordinary surface contact coating, due to the different synthesis atmospheres, the LiB3H8 material is synthesized and then solid-solid fusion contact occurs with the surface of the ternary material, the contact surface is tight and firm, the lithium ion migration transition is more smooth, and during the cycle process, the volume change of the particles due to the change of the crystal lattice volume and the distortion of the crystal lattice after the material extracts lithium ions increases the stress, the firm interface generated by fusion is not easy to separate, thereby avoiding the problem that lithium ions cannot diffuse after the interface separates in the common solid-state lithium ion battery, and further improving the cycle retention rate, capacity and rate performance of the battery material. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the accompanying drawings required by the specific embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0030] Figure 1 is the SEM morphology diagram of the ternary positive electrode material coated with solid-state electrolyte prepared in Example 1 of the present application;

[0031] Figure 2 is the SEM morphology diagram of the positive electrode material prepared in Comparative Example 1 of the present application;

[0032] Figure 3 is the cycle test diagram of Examples 1-3 and Comparative Examples 1-4 of the present application. DETAILED DESCRIPTION

[0033] The following examples are provided to better further understand the present application, and are not limited to the best mode, and do not limit the content and protection scope of the present application. Any person under the inspiration of the present application or the combination of the present application with other prior art features can obtain any product same or similar to the present application, which falls within the protection scope of the present application.

[0034] The specific experimental steps or conditions not mentioned in the examples can be performed according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments not mentioned by the manufacturer are conventional reagent products that can be obtained by market purchase.

[0035] Example 1

[0036] The present embodiment provides a preparation method of a ternary positive electrode material coated with solid-state electrolyte, and the specific steps are as follows:

[0037] 1) 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2 were weighed and uniformly mixed, then placed in an oxygen atmosphere, heated to 700℃ and heat treated for 10 h, cooled in the furnace and crushed through a 250 mesh sieve to obtain a ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0038] 2) In a glove box (waterless and oxygen-free environment), 5 mol of nano-lithium powder was placed in a schlenk reaction bottle, 15 L of 1 mol / L borane tetrahydrofuran solution (THF·BH3) was added, and the reaction was continuously stirred at room temperature (25°C) for 8 hours. The insoluble matter was removed by filtration, the filtrate was concentrated to remove the solvent to obtain a solid, which was washed with toluene, and finally vacuum concentrated to remove the solvent to obtain LiB3H8. The material obtained in step 2) was subjected to elemental analysis, and the test results are shown in Table 1 below:

[0039] Table 1

[0040]

[0041]

[0042] From Table 1, it can be seen that the molar ratio of the synthesized solid-state electrolyte Li:B:H = 1:2.90:7.86, and considering the instrument test error, the synthesized solid-state electrolyte material is close to LiB3H8.

[0043] 3) 1 mol of LiB3H8 obtained in step 2) and 10 mol of ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2 obtained in step 1) were weighed and uniformly mixed, then placed in a nitrogen atmosphere, heated to 450°C and heat treated for 5 h, cooled with the furnace and crushed through a 250 mesh sieve to obtain a solid-state electrolyte coated ternary positive electrode material, the SEM morphology of which is shown in Figure 1 .

[0044] Example 2

[0045] The present embodiment provides a preparation method of a solid-state electrolyte coated ternary positive electrode material, and the specific steps are as follows:

[0046] 1) 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2 were weighed and uniformly mixed, then placed in an oxygen atmosphere, heated to 700°C and heat treated for 10 h, cooled with the furnace and crushed through a 250 mesh sieve to obtain a ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0047] 2) In a glove box (anhydrous and anaerobic environment), 5 mol of nano-lithium powder was placed in a schlenk reaction bottle, 15 L of tetrahydrofuran solution (THF·BH3) with a concentration of 1 mol / L of borane was added, and the reaction was continuously stirred at room temperature (25°C) for 8 hours. The insoluble matter was removed by filtration, the filtrate was concentrated to remove the solvent to obtain a solid, which was washed with toluene, and finally vacuum concentrated to remove the solvent to obtain LiB3H8. The material obtained in step 2) was subjected to elemental analysis, and the test results are shown in Table 1.

[0048] 3) 2 mol of LiB3H8 obtained in step 2) and 10 mol of the ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2 obtained in step 1) were weighed and uniformly mixed, then placed in a nitrogen atmosphere, heated to 450°C and heat treated for 5 h, cooled with the furnace and crushed through a 250 mesh sieve to obtain a solid-state electrolyte-coated ternary positive electrode material.

[0049] Example 3

[0050] The present embodiment provides a preparation method of a solid-state electrolyte-coated ternary positive electrode material, and the specific steps are as follows:

[0051] 1) 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2 were weighed and uniformly mixed, then placed in an oxygen atmosphere, heated to 700°C and heat treated for 10 h, cooled with the furnace and crushed through a 250 mesh sieve to obtain a ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0052] 2) In a glove box (anhydrous and anaerobic environment), 5 mol of nano-lithium powder was placed in a schlenk reaction bottle, 15 L of tetrahydrofuran solution (THF·BH3) with a concentration of 1 mol / L of borane was added, and the reaction was continuously stirred at room temperature (25°C) for 8 hours. The insoluble matter was removed by filtration, the filtrate was concentrated to remove the solvent to obtain a solid, which was washed with toluene, and finally vacuum concentrated to remove the solvent to obtain LiB3H8. The material obtained in step 2) was subjected to elemental analysis, and the test results are shown in Table 1.

[0053] 3) 0.2 mol of LiB3H8 obtained in step 2) and 10 mol of the ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05After mixing uniformly, the mixture was placed in an oxygen atmosphere, heated to 700°C for 10 h, cooled in the furnace and crushed to pass through a 250 mesh sieve to obtain the ternary positive electrode material LiNi

[0054] Comparative Example 1

[0055] The present comparative example provides a preparation method of a ternary positive electrode material, and the specific steps are as follows:

[0056] 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2, and after mixing uniformly, the mixture was placed in an oxygen atmosphere, heated to 700°C for 10 h, cooled in the furnace and crushed to pass through a 250 mesh sieve to obtain the ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2, and the SEM morphology thereof is shown in Figure 2

[0057] Comparative Example 2

[0058] The present comparative example provides a preparation method of an oxide-coated ternary positive electrode material, and the specific steps are as follows:

[0059] 1) 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2, and after mixing uniformly, the mixture was placed in an oxygen atmosphere, heated to 700°C for 10 h, cooled in the furnace and crushed to pass through a 250 mesh sieve to obtain the ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2;

[0060] 2) In a glove box (water-free and oxygen-free environment), 5 mol of nano lithium powder was placed in a schlenk reaction bottle, 15 L of 1 mol / L borane tetrahydrofuran solution (THF·BH3) was added, and the reaction was continuously stirred at room temperature (25°C) for 8 hours. The insoluble matter was removed by filtration, the filtrate was concentrated to remove the solvent to obtain a solid, and toluene was used for washing, and finally vacuum concentration was performed to remove the solvent to obtain LiB3H8;

[0061] 3) 1 mol of LiB3H8 obtained in step 2) and the ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2 obtained in step 1) were mixed uniformly, and then placed in an oxygen atmosphere, heated to 450°C for 5 h, cooled in the furnace and crushed to pass through a 250 mesh sieve to obtain the oxide-coated ternary positive electrode material.​

[0062] Comparative Example 3

[0063] The present comparative example provides a preparation method of a ternary positive electrode material, and the specific steps are as follows:

[0064] 1) 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2are weighed and uniformly mixed, then placed in an oxygen atmosphere, heated to 700°C for 10 h of heat treatment, cooled with the furnace and crushed to pass through a 250 mesh sieve to obtain a ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0065] 2) 1 mol of LiBH4 and the ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2obtained in step 1) are uniformly mixed, then placed in a nitrogen atmosphere, heated to 450°C for 5 h of heat treatment, cooled with the furnace and crushed to pass through a 250 mesh sieve to obtain a LiBH4-coated ternary positive electrode material.

[0066] Comparative Example 4

[0067] The present comparative example provides a preparation method of a ternary positive electrode material, and the specific steps are as follows:

[0068] 1) 10 mol of LiOH, 10.0 mol of Ni 0.9 Co 0.05 Mn 0.05 (OH)2are weighed and uniformly mixed, then placed in an oxygen atmosphere, heated to 700°C for 10 h of heat treatment, cooled with the furnace and crushed to pass through a 250 mesh sieve to obtain a ternary positive electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0069] 2) In a glove box (water-free and oxygen-free environment), 5 mol of nano lithium powder is placed in a schlenk reaction bottle, 15 L of a 1 mol / L borane tetrahydrofuran solution (THF·BH3) is added, and the reaction is continuously stirred at room temperature (25°C) for 8 hours. The insoluble matter is removed by filtration, the filtrate is concentrated to remove the solvent to obtain a solid, which is washed with toluene, and finally vacuum concentrated to remove the solvent to obtain LiB3H8;

[0070] 3) 1 mol of LiB3H8 obtained in step 2) and the ternary positive electrode material LiNi 0.9 Co 0.05 Mn0.05 After mixing uniformly, the mixture was dried in a vacuum oven at 100℃ for 1d, and then crushed to pass through a 250-mesh screen to obtain the simple mixed coated solid-state electrolyte coated ternary cathode material.

[0071] Test Example 1

[0072] The cathode materials prepared in the above examples and comparative examples were subjected to electrochemical performance testing. The electrochemical performance testing procedure was as follows: the cathode material, carbon black and polyvinylidene fluoride (PVDF) were weighed according to a mass ratio of 95:2.5:2.5, mixed, and then a solvent N-methyl pyrrolidone (NMP) was added according to a solid-liquid ratio of 2:1 to prepare a cathode slurry. The slurry was uniformly coated on an aluminum foil, which was baked at 105℃ for 2h. The baked electrode sheet was cut and then pressed in a tablet press (the compaction density was 3.2g / cm 3 ), and small round sheets were cut out. The small round sheets were assembled in a nitrogen atmosphere, in which the water vapor and oxygen content was less than 0.1ppm. The small round sheets were placed in a positive electrode side of a button cell shell, with the coated surface facing away from the positive electrode. Polyacrylonitrile (PAN) + Li7La3Zr2O 12 (LLZO) (the mass ratio of PAN:LLZO was 1:9) was added, and then a negative electrode sheet (pure lithium sheet), a gasket and a spring were added. The button cell was sealed to form a CR2032 button cell. The charge and discharge system was as follows: the charge cut-off voltage was 4.3V, the discharge cut-off voltage was 3.0V; the first cycle was 0.1C charging and 0.1C discharging; the second cycle was 0.5C charging and 0.5C discharging; the third cycle was 1.0C charging and 1.0C discharging; and then 1C charging and 1C discharging were cycled for 500 times for cycle retention rate testing (as shown in Figure 3 Table 2).

[0073] Table 2

[0074]

[0075] As shown in Table 2, the 0.1C discharge specific capacity of the solid-state electrolyte coated ternary cathode material prepared in the present application was greater than or equal to 212.0mAh / g, the 0.5C discharge specific capacity was greater than or equal to 201.3mAh / g, the 1C discharge specific capacity was greater than or equal to 196.5mAh / g, and the 500 cycle performance was greater than or equal to 90.78%.

[0076] As can be seen from the comparison between Example 1 and Comparative Example 1, the ternary material coated with solid-state electrolyte in the present example was applied in a solid-state battery. The cathode material was coated with solid-state electrolyte in advance, and thus had good contact with the electrolyte in the solid-state battery. After the lithium ions were released from the ternary cathode, they passed through the three-dimensional channel of the surface-coated solid-state electrolyte and smoothly entered the electrolyte in the solid-state battery. Therefore, the material had high capacity and good cycle performance.

[0077] From the comparison of Example 1 and Comparative Example 2, it can be seen that after the LiB3H8 material in Comparative Example 2 is coated and sintered in an oxygen atmosphere, the coated solid electrolyte is oxidized, the crystal form of the surface coating changes, the three-dimensional diffusion path of lithium ions is lost, and the capacity and cycle life are reduced.

[0078] From the comparison of Example 1 and Comparative Example 3, it can be seen that after the LiBH4 material in Comparative Example 3 is coated, the ion conduction ability of the coating LiBH4 is weak, which hinders the lithium ions from entering the electrolyte of the battery, and the capacity and cycle life are reduced.

[0079] From the comparison of Example 1 and Comparative Example 4, it can be seen that after the LiB3H8 material in Comparative Example 4 is coated, the treatment is vacuum oven, and the sintering temperature is 100°C, which is insufficient to fuse the LiB3H8 and the ternary material matrix, and there is a physical gap at the contact surface, the ion conduction ability of the interface is poor, which seriously hinders the lithium ions from entering the coated electrolyte, and the capacity and cycle life are reduced.

[0080] From the comparison of Example 1 and Comparative Example 4, it can be seen that after the LiB3H8 material in Comparative Example 4 is coated, the treatment is vacuum oven, and the sintering temperature is 100°C, which is insufficient to fuse the LiB3H8 and the ternary material matrix, and there is a physical gap at the contact surface, the ion conduction ability of the interface is poor, which seriously hinders the lithium ions from entering the coated electrolyte, and the capacity and cycle life are reduced. Figure 1 Figure 2 From the comparison of Example 1 and Comparative Example 4, it can be seen that after the LiB3H8 material in Comparative Example 4 is coated, the treatment is vacuum oven, and the sintering temperature is 100°C, which is insufficient to fuse the LiB3H8 and the ternary material matrix, and there is a physical gap at the contact surface, the ion conduction ability of the interface is poor, which seriously hinders the lithium ions from entering the coated electrolyte, and the capacity and cycle life are reduced.

[0081] Obviously, the above examples are merely examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.​

Claims

1. A method for preparing a solid-state electrolyte-coated ternary cathode material, characterized in that, include: According to the stoichiometric ratio of the ternary material, the nickel-cobalt-manganese hydroxide precursor and the lithium source were weighed and mixed to obtain a mixture. The mixture was placed in an oxygen-containing atmosphere for a first sintering treatment to obtain the ternary material. The LiB3H8 material was obtained. The ternary material and the LiB3H8 material were mixed and placed in an inert atmosphere for a second sintering treatment to obtain the final product.

2. The production method according to claim 1, characterized by, The chemical formula of the ternary material is Li a Ni x Co y Mn 1-x-y O2, wherein 1.0≤a≤1.1, 0.5 And / or, the molar ratio of the ternary material to the LiB3H8 material is 10:(0.2-2.0); And / or, the lithium source includes lithium hydroxide; And / or, the oxygen-containing atmosphere is oxygen or air.

3. The production method according to claim 2, characterized by, The ternary material has a chemical formula of LiNi 0.9 Co 0.05 Mn 0.05 O2.

4. The production method according to claim 1 or 2, characterized by, The temperature of the first sintering treatment is 600-800℃; And / or, the holding time for the first sintering treatment is 8-12 h; And / or, the temperature of the second sintering treatment is 400-500℃; And / or, the holding time for the second sintering treatment is 4-6 h; And / or, the inert atmosphere is nitrogen and / or argon.

5. The production method according to claim 4, characterized by, The temperature of the first sintering treatment is 700℃; And / or, the holding time for the first sintering treatment is 10 h; And / or, the temperature of the second sintering treatment is 450°C; And / or, the holding time for the second sintering treatment is 5 h.

6. The production method according to claim 1 or 2, characterized by, The process of obtaining the LiB3H8 material includes: adding nano-lithium powder to a tetrahydrofuran solution of borane in an anhydrous and oxygen-free environment to carry out the reaction.

7. The production method according to claim 6, characterized by, The concentration of the borane in tetrahydrofuran solution is 0.5-1.5 mol / L; And / or, based on a molar amount of 5 mol of lithium nanoparticles, the volume of the tetrahydrofuran solution of borane is 15-20 L; And / or, the reaction is carried out at room temperature; And / or, the reaction duration is 6-10 h; And / or, the reaction is also carried out with stirring.

8. The production method according to claim 7, characterized by, The concentration of the borane tetrahydrofuran solution is 1 mol / L; And / or, based on a molar amount of 5 mol of lithium nanoparticles, the volume of the tetrahydrofuran solution of borane is 15 L; And / or, the reaction duration is 8 h.

9. A solid-state electrolyte-coated ternary cathode material, characterized in that, It is prepared by the method for preparing solid electrolyte-coated ternary materials as described in any one of claims 1-8.

10. A solid-state lithium-ion battery, characterized by, The solid-state lithium-ion battery includes the solid electrolyte-coated ternary cathode material as described in claim 9.

Images