A high-nickel lithium-rich manganese-based all-solid-state battery positive electrode material and a preparation method thereof

Abstract

The application discloses a high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material, which comprises a lithium nickel cobalt manganese oxide core and a NiO layer coated on the surface of the core; the weight percentage of the NiO in the high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material is 1-5%. The positive electrode material is the lithium nickel cobalt manganese oxide coated with the NiO layer, the high-chemical-stability NiO coating layer on the surface of the positive electrode material can act as a protective layer at the positive electrode / electrolyte interface, on the one hand, can stabilize the lattice oxygen on the surface of the positive electrode material, and reduce the phase degradation of the positive electrode material in the cycle process; on the other hand, can also act as a buffer layer to limit the direct contact of the positive electrode material with the solid-state electrolyte, so as to weaken the side reaction between the positive electrode material and the solid-state electrolyte, finally improve the specific capacity and cycle performance of the solid-state battery. The application further discloses a preparation method of the high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material, a full-solid-state battery positive electrode material and a full-solid-state battery.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lithium ion battery materials, in particular to a high-nickel lithium-rich manganese-based all-solid-state battery positive electrode material and a preparation method thereof. BACKGROUND

[0002] The energy density and safety performance of all-solid-state batteries are significantly superior to those of liquid-state batteries, and the all-solid-state batteries have excellent commercial prospects. The positive electrode, the negative electrode and the electrolyte are key components of the battery. In the past few decades, many breakthroughs have been made in the negative electrode and the electrolyte, and the positive electrode material has become an important factor restricting the performance improvement of lithium batteries, accounting for about 30-40% of the cost of lithium ion batteries. Compared with the current positive electrode material, the lithium-rich manganese-based positive electrode material has the advantages of high discharge specific capacity (> 250 mAh / g) and low cost, and is expected to become the next generation of lithium ion battery positive electrode material.

[0003] The lithium-rich manganese-based positive electrode material has a special "Li-O-Li" structure and can undergo lattice oxygen redox reaction at high voltage, thereby obtaining high specific capacity. However, in the process of lattice oxygen redox, part of the oxygen will be irreversibly oxidized to oxygen and form oxygen vacancies, which can reduce the migration energy of transition metal ions to the lithium layer, thereby inducing structural transformation and ultimately causing problems such as low initial coulombic efficiency, voltage decay and hysteresis of the battery. On the other hand, the generated oxygen attacks the electrolyte, forming a large amount of by-products at the positive electrode / electrolyte interface, hindering the lithium ion transmission at the interface, and deteriorating the cycle performance and rate performance of the lithium-rich manganese-based positive electrode material.

[0004] Current performance optimization methods for lithium-rich manganese-based positive electrode materials include coating, doping, electrode structure design, etc., aiming to solve the problems of oxygen evolution and slow electron / ion transmission inherent in lithium-rich manganese-based positive electrode materials. For example, Zhang Qiang et al. introduced stable polyanion SO3 2- substituted lattice oxygen O 2- , stabilized the positive electrode / electrolyte interface, and to a certain extent, inhibited the release of oxygen, significantly improving the initial charge-discharge efficiency and cycle performance of the lithium-rich manganese-based material. Pan Hongge et al. adjusted the ratio of Ni and Co in the lithium-rich manganese-based material, which improved the electronic and ionic conductivities of the material by 4 orders of magnitude, and obtained ultra-high discharge specific capacity and 1000 cycle stability. However, these methods are relatively complex and difficult to realize large-scale production and application. Therefore, it is necessary to develop a simpler and more effective method to improve the structural stability of lithium-rich manganese-based positive electrode materials and the electrochemical performance of solid-state batteries. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a high-nickel lithium-rich manganese-based all-solid-state battery positive electrode material and a preparation method thereof.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows: a high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material, comprising a lithium nickel cobalt manganese oxide core and a NiO layer coated on the surface of the core;

[0007] The chemical formula of the lithium nickel cobalt manganese oxide core is shown as formula (I):

[0008] aLi2MnO3·(1-a)LiMn 1 / 3 Ni 1 / 3 Co 1 / 3 O2(I)

[0009] wherein 0.4 < a < 0.6;

[0010] In the high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material, the weight percentage of the NiO is 1-5%.

[0011] The high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material of the present application has a NiO layer coated on the surface of the lithium nickel cobalt manganese oxide core, and when the weight percentage of the NiO in the positive electrode material is 1-5% (such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%, etc., but not limited to the above contents), the specific capacity and cycle stability of the material can be improved. The inventors speculate that it may be due to the chemical stability of the surface NiO coating layer, which acts as a protective layer at the positive electrode / electrolyte interface, on the one hand, it can stabilize the lattice oxygen on the surface of the positive electrode material, and reduce the phase degradation thereof during the cycle process; on the other hand, it can also act as a buffer layer to limit the direct contact of the positive electrode material with the solid-state electrolyte, thereby weakening the side reaction between the positive electrode material and the solid-state electrolyte, and finally improving the specific capacity and cycle performance of the solid-state battery.

[0012] The lithium nickel cobalt manganese oxide core is a spherical particle, and the D50 (secondary particle) is 1-10 μm (such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm, etc., but not limited thereto), and the thickness of the NiO layer is 5-20 nm (such as 5 nm, 7 nm, 9 nm, 11 nm, 13 nm, 15 nm, 17 nm, 19 nm, and 20 nm, etc., but not limited thereto). The D50 particle size of the lithium nickel cobalt manganese oxide core can be obtained by scanning electron microscope test statistics, and the average value is obtained after testing the particle size of 50 particles. Preferably, the D50 particle size of the primary particles of the lithium nickel cobalt manganese oxide is 0.1-1 μm. The thickness of the NiO layer is obtained by transmission electron microscope (TEM) test.

[0013] Preferably, the average particle size of the lithium nickel manganese cobalt oxide core is 3-7 μm. The lithium nickel manganese cobalt oxide can be commercially available or prepared by conventional methods known in the art, such as the method mentioned in Jun Wang, Xiaoyin Yao, Xufeng Zhou and Zhaoping Liu* Synthesis and electrochemical properties of layered lithium transition metal oxides [J] J. Mater. Chem., 2011, 21, 2544-2549.

[0014] Preferably, in the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material, the weight percentage of NiO is 2-4%. NiO at this content can exhibit better specific capacity and cycle stability.

[0015] The application also provides a preparation method of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material, comprising the following steps:

[0016] S1. Obtain lithium nickel manganese cobalt oxide particles;

[0017] S2. Mix the lithium nickel manganese cobalt oxide particles and nickel salt uniformly to obtain a mixture, sinter the mixture to decompose the nickel salt into nickel oxide, and cool to obtain the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material.

[0018] The high-nickel lithium-rich manganese-based full solid-state battery positive electrode material can be prepared by mixing the lithium nickel manganese cobalt oxide particles and the nickel salt, sintering the mixture to decompose the nickel salt into nickel oxide, and forming a rock salt phase of the nickel oxide on the surface of the lithium nickel manganese cobalt oxide particles, thereby constructing a surface stable layer. The process has strong production stability and can be applied to batch production of materials.

[0019] Preferably, in S2, the mixing is: stirring and mixing the lithium nickel manganese cobalt oxide particles and the nickel salt uniformly in a solvent, and removing the solvent; preferably, the solvent is an organic solvent; the organic solvent is preferably one or a mixture of several of alcohol, aromatic hydrocarbon, ether, ketone, and more preferably ethanol; the amount of the solvent added is 1 g of the mixture / 10-30 mL of the solvent. The removal of the solvent can be performed by conventional means such as volatilization under negative pressure, flowing gas atmosphere, heating (preferably below 100°C), etc. The sintering is preferably performed in a muffle furnace. The heating rate for heating to the sintering temperature is preferably 3-10°C / min, and the sintering atmosphere is air atmosphere. The cooling is preferably natural cooling to room temperature in the furnace.

[0020] Preferably, the nickel salt is a salt capable of decomposing into nickel oxide after sintering, preferably, the nickel salt is at least one of nickel nitrate and hydrates thereof, nickel sulfate and hydrates thereof, and nickel hydroxide.

[0021] Preferably, the nickel salt is added in an amount such that the weight percentage of NiO in the high-nickel lithium-rich manganese-based full-solid-state battery cathode material is 1-5%.

[0022] Preferably, the nickel salt is nickel nitrate hexahydrate, and the nickel nitrate hexahydrate accounts for 1-5% of the total molar ratio of the mixture.

[0023] Preferably, when the nickel salt is nickel nitrate hexahydrate, the sintering temperature is 350-750°C, and the sintering time is 3-8 hours.

[0024] More preferably, when the nickel salt is nickel nitrate hexahydrate, the sintering temperature of the mixture is 350-600°C, more preferably 500-600°C, and the sintering time is 5.5-6.5 hours. The material obtained at a temperature of 500-600°C has higher specific capacity and better cycle performance, and the inventors believe that the possible reason is that at a lower sintering temperature (about 350°C), the nickel nitrate hexahydrate mainly undergoes dehydration and partial decomposition of nitrate, and does not fully form NiO. At 500-600°C, the nickel nitrate hexahydrate is completely decomposed, achieving surface high-nickelization, but at more than 700°C, the NiO enters the bulk phase of the material, which hinders the transport of lithium ions, thereby limiting the electrochemical performance. Therefore, at 500-600°C, the nickel oxide is uniformly coated on the surface of the lithium nickel cobalt manganese oxide particles, thereby constructing a surface stable layer and achieving better material performance.

[0025] Preferably, the nickel nitrate hexahydrate accounts for 2-4%, more preferably 2-3%, of the total molar ratio of the mixture.

[0026] The purpose of the present application is also to provide a full-solid-state battery cathode material, comprising: the high-nickel lithium-rich manganese-based full-solid-state battery cathode material described above or prepared by the method described above.

[0027] Preferably, the full-solid-state battery cathode material further comprises a halide solid-state electrolyte, a conductive additive, and a binder. Further preferably, the full-solid-state battery cathode material comprises the following ingredients in the following weight percentages: cathode active material 50-85%, halide solid-state electrolyte 15-50%, and conductive additive 0.5-10%.

[0028] Preferably, the halide solid-state electrolyte has the chemical formula Li6PS5Cl and / or Li a MX b , wherein Lia MX b In some embodiments, M is selected from at least one of Al, Ga, In, Sc, Y and La-based elements; X is selected from at least one of F, CI and Br; 0≤a≤10; 1≤b≤13; the halide solid-state electrolyte is more preferably at least one of Li6PS5CI and Li3InCI6; and the conductive additive is preferably selected from at least one of conductive carbon black, carbon nanotube, carbon nanofiber, acetylene black, conductive graphite and graphene.

[0029] The present application also provides a full solid-state battery comprising the full solid-state battery cathode material, a solid-state electrolyte layer and a metal anode. The metal anode is preferably selected from metal indium, metal lithium, alloy, carbon anode, tin-based anode or nano-oxide. The solid-state electrolyte is preferably selected from one or more of halide, sulfide, oxide and polymer. The solid-state electrolyte layer is preferably a double-layer solid-state electrolyte, with a Li3InCI6 solid-state electrolyte layer close to the cathode side and a Li6PS5CI solid-state electrolyte layer close to the anode side.

[0030] Compared with the prior art, the present application has the following beneficial effects: the high-nickel lithium-rich manganese-based full solid-state battery cathode material of the present application is a nickel cobalt lithium manganate coated with a NiO layer. The chemical stability of the surface NiO coating layer makes it act as a protective layer at the cathode / electrolyte interface, which can stabilize the lattice oxygen on the surface of the cathode material and reduce the phase degradation of the cathode material during the cycle process, and also can act as a buffer layer to limit the direct contact between the cathode material and the solid-state electrolyte, thereby weakening the side reaction between the cathode material and the solid-state electrolyte, and further improving the specific capacity and cycle stability of the material, improving the electrochemical performance of the material, and especially when applied to a full solid-state battery, the specific capacity and cycle performance of the battery can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 SEM image of nickel cobalt lithium manganate particles according to Comparative Example 1;

[0032] Figure 2 (a) is a particle size distribution histogram of primary particles of nickel cobalt lithium manganate particles according to Comparative Example 1, and (b) is a particle size distribution histogram of secondary particles of nickel cobalt lithium manganate particles according to Comparative Example 1;

[0033] Figure 3 SEM images of high-nickel lithium-rich manganese-based full solid-state battery cathode materials according to Examples 1-9, wherein Example 1 is (a), Example 2 is (b), Example 3 is (c), Example 4 is (d), Example 5 is (e), Example 6 is (f), Example 7 is (g), Example 8 is (h), and Example 9 is (i);

[0034] Figure 4 SEM-EDS surface scanning distribution of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in Example 5;

[0035] Figure 5 The first charge-discharge curve of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in Example 5 and the comparative example;

[0036] Figure 6 The cycle performance graph of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in Example 5 and the comparative example;

[0037] Figure 7 (a) is the linear TEM scanning graph of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in Example 5, and (b) is the linear TEM-EDS intensity signal graph corresponding to (a);

[0038] Figure 8 The HRTEM graph and the FFT graph of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in Example 5. DETAILED DESCRIPTION

[0039] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in conjunction with the drawings and specific embodiments.

[0040] In the following examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0041] Example 1

[0042] The high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in the present application includes a lithium nickel cobalt manganese oxide core, a NiO layer coated on the surface of the core; the lithium nickel cobalt manganese oxide core is a lithium nickel cobalt manganese oxide particle Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2, purchased from Kurand, with a D50 (secondary particle) of 5.67 μm and a D50 particle size of 0.46 μm for the primary particle, and the SEM graph thereof is shown in Figure 1 , and the particle size distribution statistical graph of the primary particle and the secondary particle is shown in Figure 2 .

[0043] The preparation method of the high-nickel lithium-rich manganese-based full solid-state battery positive electrode material described in the present embodiment includes the following steps:

[0044] S1. Obtain a lithium nickel cobalt manganese oxide particle;

[0045] S2. Weigh the lithium nickel cobalt manganese oxide particles, weigh the nickel nitrate hexahydrate according to 1% of the total moles of the lithium nickel cobalt manganese oxide particles and the nickel nitrate hexahydrate, and add 1 g of the mixture to 20 mL of 95% ethanol solution, stir to mix uniformly, dry at 80°C, obtain the mixture, place the mixture in a corundum square boat, move to a muffle furnace, heat to 350°C at a heating rate of 5°C / min under an air atmosphere, keep for 6 hours, after the end, naturally cool to room temperature with the furnace, and obtain the high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material.

[0046] Example 2

[0047] The difference between this example and Example 1 is that the amount of nickel nitrate hexahydrate added is different. In this example, the amount of nickel nitrate hexahydrate added is 2.5% of the total moles of the lithium nickel cobalt manganese oxide particles and the nickel nitrate hexahydrate.

[0048] Example 3

[0049] The difference between this example and Example 1 is that the amount of nickel nitrate hexahydrate added is different. In this example, the amount of nickel nitrate hexahydrate added is 5% of the total moles of the lithium nickel cobalt manganese oxide particles and the nickel nitrate hexahydrate.

[0050] Example 4

[0051] The difference between this example and Example 1 is the sintering temperature in S2. In this example, the sintering temperature is 550°C, denoted as LLO(550, 1%).

[0052] Example 5

[0053] The difference between this example and Example 1 is that the amount of nickel nitrate hexahydrate added and the sintering temperature are different. In this example, the amount of nickel nitrate hexahydrate added is 2.5% of the total moles of the lithium nickel cobalt manganese oxide particles and the nickel nitrate hexahydrate, and the sintering temperature is 550°C, denoted as LLO(550, 2.5%).

[0054] Example 6

[0055] The difference between this example and Example 1 is that the amount of nickel nitrate hexahydrate added and the sintering temperature are different. In this example, the amount of nickel nitrate hexahydrate added is 5% of the total moles of the lithium nickel cobalt manganese oxide particles and the nickel nitrate hexahydrate, and the sintering temperature is 550°C, denoted as LLO(550, 5%).

[0056] Example 7

[0057] The difference between this example and Example 1 is the sintering temperature in S2. In this example, the sintering temperature is 750°C.

[0058] Example 8

[0059] The difference between this embodiment and Example 1 is that the amount of nickel nitrate hexahydrate added and the sintering temperature are different. In this embodiment, the amount of nickel nitrate hexahydrate added is 2.5% of the total moles of lithium nickel cobalt manganese oxide particles and nickel nitrate hexahydrate, and the sintering temperature is 750°C.

[0060] Example 9

[0061] The difference between this embodiment and Example 1 is that the amount of nickel nitrate hexahydrate added and the sintering temperature are different. In this embodiment, the amount of nickel nitrate hexahydrate added is 2.5% of the total moles of lithium nickel cobalt manganese oxide particles and nickel nitrate hexahydrate, and the sintering temperature is 750°C.

[0062] Comparative Example

[0063] This comparative example is the lithium nickel manganese oxide particles Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2, denoted as LLO.

[0064] Example

[0065] Preparation of all-solid-state battery positive electrode material: The high-nickel lithium-rich manganese-based all-solid-state battery positive electrode material described in the examples and comparative examples, electrolyte Li3InCl6, and conductive additive C65 are mixed in a weight ratio of 66.5:28.5:5 to obtain the positive electrode material.

[0066] Assembly of all-solid-state battery: 55 mg of Li6PS5Cl is placed in a pressurized mold (diameter 10 mm) and compacted under a pressure of 1 ton, and then 55 mg of Li3InCl6 is added on top and compacted under the same pressure of 1 ton, and then 10 mg of all-solid-state battery positive electrode material is added on top of the Li3InCl6 electrolyte and compacted under a pressure of 3 tons for 2 minutes, and then a high-purity indium sheet (thickness 0.1 mm), a lithium sheet (0.05 mm), and a copper sheet (0.008 mm) are placed in sequence on one side of the Li6PS5Cl electrolyte sheet and placed in a battery mold, thereby completing the assembly of the all-solid-state battery.

[0067] The assembled all-solid-state battery is tested for performance using a charge-discharge tester, with an ambient temperature of 25°C, a working voltage range of 1.4-4.2V, and first performing 3 activation operations on the battery at a current of 0.1C.

[0068] The test results are shown in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] From the results of Table 1, it can be seen that the addition of nickel nitrate hexahydrate in the amount of 1-5% of the total moles of lithium nickel cobalt manganese oxide particles and nickel nitrate hexahydrate to the lithium nickel manganese oxide material, after sintering, forms a positive electrode material having a NiO weight percentage content of 1-5%, and the discharge performance and capacity retention rate of the positive electrode material are superior to those of the lithium nickel manganese oxide material without NiO coating, and can reach a discharge performance of more than 140 mAh / g at the first circle (0.1C) and a capacity retention rate of more than 53% after 300 circles. In particular, when the sintering temperature is 550°C and the amount of nickel nitrate hexahydrate is 2.5% of the total moles of lithium nickel cobalt manganese oxide particles and nickel nitrate hexahydrate, the first discharge performance and capacity retention rate after 300 circles of Example 5 are optimal. Below 750°C, as the temperature increases, the surface nickel-rich treatment can improve the discharge performance of the lithium-rich manganese-based positive electrode material, and at the same temperature, the capacity retention rate increases first and then decreases with the increase of the coating amount. In particular, when the sintering temperature is 550°C and the amount of nickel nitrate hexahydrate is 2.5% of the total moles of lithium nickel cobalt manganese oxide particles and nickel nitrate hexahydrate (i.e., the theoretical weight percentage content of NiO in the high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material is about 2.77%), the performance improvement effect is the most significant. This shows that the surface nickel-rich treatment can improve the specific capacity and cycle performance of the material.

[0073] From Figure 3 It can be seen that the surface of all the example materials does not change significantly, and still maintains the morphology of the comparative sample. The surface high-nickelization does not change the morphology.

[0074] Figure 4 The SEM-EDS surface scanning distribution map of Example 5 is the EDS surface composition distribution map of the high-nickel lithium-rich manganese-based full-solid-state battery positive electrode material. As can be seen from the figure, the Ni element is uniformly distributed in the material, and the uniformity of the surface coating layer is high, and there is no obvious segregation.

[0075] From Figure 5 It can be seen that, compared with the uncoated comparative example, the first discharge performance of the positive electrode material coated with rock salt phase nickel oxide is more optimal.

[0076] From Figure 6 It can be seen that, compared with the uncoated comparative example, the specific capacity and cycle performance of the positive electrode material coated with rock salt phase nickel oxide are more optimal.

[0077] From Figure 7 It can be seen that the Ni element content on the surface of the sample with surface high-nickel is higher than that in the bulk phase, further proving the existence of the surface NiO coating.

[0078] From Figure 8 It can be seen that there is a NiO layer on the surface of the material, and at the same time, the bulk phase still maintains a typical layered structure.

[0079] Finally, it should be noted that the above examples are only intended to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. An all-solid-state battery, characterized in that, This includes all-solid-state battery cathode materials, solid electrolyte layers, and metal anodes; The all-solid-state battery cathode material includes the following components: high-nickel lithium-rich manganese-based all-solid-state battery cathode material, halide solid electrolyte, conductive additives, and binders; The chemical formula of the halide solid electrolyte is Li3InCl6; The solid electrolyte layer is a double-layer solid electrolyte, with a Li3InCl6 solid electrolyte layer on the side near the positive electrode and a Li6PS5Cl solid electrolyte layer on the side near the negative electrode. The high-nickel lithium-rich manganese-based all-solid-state battery cathode material includes a lithium nickel cobalt manganese oxide core and a NiO layer coated on the surface of the core. The chemical formula of the lithium nickel cobalt manganese oxide core is shown in formula (I): aLi2MnO3•(1-a)LiMn 1 / 3 Ni 1 / 3 Co 1 / 3 O2 (I) Where 0.4 < a < 0.6; In the high-nickel lithium-rich manganese-based all-solid-state battery cathode material, the NiO content is 2.5% to 4% by weight. The preparation method of the high-nickel lithium-rich manganese-based all-solid-state battery cathode material includes the following steps: S1. Obtain lithium nickel cobalt manganese oxide particles; S2. Mix lithium nickel cobalt manganese oxide particles and nickel salt evenly to obtain a mixture. Sinter the mixture to decompose the nickel salt into nickel oxide. Cool to obtain the high-nickel lithium-rich manganese-based all-solid-state battery cathode material. The sintering temperature is 500~600℃, and the sintering time is 5.5-6.5 hours.

2. The all-solid-state battery as described in claim 1, characterized in that, The lithium nickel cobalt manganese oxide core is a spherical particle with a D50 of 1~10μm, and the NiO layer has a thickness of 5~20nm.

3. The all-solid-state battery as described in claim 1, characterized in that, The average particle size of the lithium nickel cobalt manganese oxide core is 3~7μm.

4. The all-solid-state battery as described in claim 3, characterized in that, The nickel salt is at least one of nickel nitrate and its hydrate, nickel sulfate and its hydrate, and nickel hydroxide.

5. The all-solid-state battery as described in claim 4, characterized in that, The nickel salt is nickel nitrate hexahydrate, and the nickel nitrate hexahydrate accounts for 1 to 5% of the total molar ratio of the mixture.

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