Composite polycrystalline positive electrode material, electrode plate and all-solid-state battery

Abstract

The invention discloses a composite polycrystalline positive electrode material which is prepared by permeating and coating a polycrystalline positive electrode material with an oxyhalide solid electrolyte, and the oxyhalide solid electrolyte comprises one or more of Li-Ta-O-Cl, Li-Nb-O-Cl, Li-Zr-O-Cl and Li-Al-O-Cl. The specific oxyhalide electrolyte is adopted to carry out permeation coating on the polycrystalline positive electrode material, uniform coating on the surface of the polycrystalline positive electrode material and grain boundaries in particles is completed, capacity utilization in the particles of the polycrystalline positive electrode material is achieved, and the capacity utilization rate of the particles of the polycrystalline positive electrode material is improved through the coating effect of the oxyhalide with high ionic conductivity. Ion transmission inside and in gaps of the polycrystalline positive electrode material particles is regulated, interface impedance is reduced, energy density is improved, and the application prospect is wide.

Description

Technical Field

[0001] The present invention relates to the field of all-solid-state batteries, and in particular to a composite polycrystalline positive electrode material, an electrode sheet and an all-solid-state battery. Background Art

[0002] Lithium-ion batteries are excellent secondary energy storage devices, highly regarded for their high energy density, high operating voltage, excellent cycling stability, large storage capacity, lightweight, and environmentally friendly features. These significant advantages have led to their widespread application in diverse fields, including mobile electronics, public transportation, new energy electric vehicles, and aerospace technology, demonstrating their enormous potential and maturity as energy storage and conversion devices.

[0003] Compared with traditional liquid batteries, solid-state batteries have significant advantages. First, solid-state electrolytes are non-volatile and non-flammable, which can effectively reduce the risk of thermal runaway, thereby significantly improving battery safety. Second, solid-state batteries can support a higher operating voltage range and achieve compatibility with high-voltage positive electrode and high-capacity negative electrode materials, which helps to further improve the energy density of the battery. In addition, solid-state electrolytes also have high chemical and electrochemical stability, which can extend the cycle life of the battery and improve long-term performance stability. In terms of design flexibility, solid-state batteries do not require liquid electrolytes and complex packaging structures, which can achieve thinner and lighter battery designs to meet the needs of portable devices and high-density integrated systems. At the same time, solid-state batteries perform well in extreme temperatures and are suitable for special fields such as aerospace and automobiles. Therefore, the multiple advantages of solid-state batteries provide an important technical foundation for the innovation and industrialization of energy storage technology.

[0004] The core of high-energy-density all-solid-state batteries lies in the optimization of positive electrode materials and the synergy of solid-state electrolytes. Compared with traditional liquid batteries, all-solid-state batteries can support the use of higher voltage positive electrode materials, such as ternary layered oxides, lithium-rich manganese-based, lithium iron phosphate, spinel, lithium cobalt oxide and other positive electrode materials. However, in solid-state batteries, polycrystalline positive electrode materials cannot perform the performance of liquid batteries. This is because polycrystalline positive electrode materials contain a large number of grain boundaries, which cannot be filled with electrolyte particles and lithium ion transport is limited. During the continuous charging and discharging process, the intercalation and deintercalation of lithium ions will also cause the volume of the positive electrode material to shrink and expand, resulting in cracks inside the positive electrode particles under long-term cycling. Therefore, single crystal materials with fewer grain boundaries and better mechanical stability are often used as positive electrodes in solid-state batteries. Such as:

[0005] CN117276488 A discloses a lithium-ion battery positive electrode active composite material and a solid-state lithium-ion battery. This method utilizes a dry or wet process to coat a lanthanide halide electrolyte on the surface of the positive electrode active material, either in a point-coating or surface-coating manner, to obtain an interfacially stable lithium-ion battery composite positive electrode material. While this method is simple to prepare, the use of organic solvents poses environmental pollution and high solvent recovery costs. Furthermore, the point-to-point solid-solid interface contact structure of the granular halide coating on the positive electrode material requires optimization.

[0006] CN118712351A discloses an oxyhalide-coated positive electrode material, a preparation method, and an all-solid-state lithium battery. The method uses a ball milling-calcination method, first mixing and ball milling a high-nickel positive electrode material powder with TaF5, and then calcining it under an inert atmosphere to obtain an oxyhalide-coated high-nickel positive electrode material. This method has a simple process, but the raw material cost is relatively high and does not involve the field of polycrystalline positive electrode materials.

[0007] CN118281190 A discloses a method for preparing and applying a LiAlO2-coated positive electrode material. This method utilizes a secondary sintering process. The positive electrode material and LiAlCl4 are uniformly mixed to form a premix, which is then sealed and heated to 200-300°C for insulation. After cooling, the mixture is washed with alkali to remove chlorine and sintered at high temperature to produce the LiAlO2-coated positive electrode material. This method is simple and reduces the production cost of the positive electrode coating material, but does not address the field of polycrystalline positive electrode materials.

[0008] CN202310597059.2 discloses a single-crystal ternary positive electrode material coated with bismuth oxyhalide and a preparation method thereof. This technical solution involves the coating of a single-crystal positive electrode material and solves the technical problems arising during the energy migration process of the single-crystal positive electrode material.

[0009] Compared to single-crystal cathode materials, polycrystalline cathode materials, due to their aggregated structure composed of multiple tiny grains, possess higher compaction density and more abundant grain boundaries. This improves film-forming properties and structural density during practical processing, thereby increasing the battery's volumetric energy density. Furthermore, the grain boundaries between polycrystalline particles provide more diffusion pathways for lithium ions, which contributes to improved rate performance and charge-discharge efficiency. Furthermore, the mature synthesis process and flexible preparation conditions of polycrystalline materials make them suitable for large-scale, low-cost production. Their large surface area facilitates surface coating or interface modification, further enhancing the material's interfacial stability and cycle life. In contrast, while single-crystal cathode materials offer structural integrity and excellent cycle stability, their large particle size and limited grain boundaries result in longer lithium ion migration paths, limiting their rate performance. Furthermore, their relatively low compaction density makes them susceptible to particle breakage during processing, and the complex and costly synthesis process presents certain limitations in practical applications. Therefore, polycrystalline cathode materials offer advantages in terms of overall performance and engineering suitability. Summary of the Invention

[0010] To address the above-mentioned issues, the present invention aims to provide a composite polycrystalline positive electrode material, an electrode sheet, and an all-solid-state battery. The polycrystalline positive electrode material, coated with an oxyhalide solid electrolyte, features a coating layer with high ionic conductivity, high voltage stability, and a permeability-enabling effect. This composite positive electrode material can effectively reduce the grain boundary impedance of the polycrystalline positive electrode material, improving its capacity, and thereby enabling a high-energy-density all-solid-state battery.

[0011] In the composite positive electrode material, the oxyhalide electrolyte uniformly covers the surface of the polycrystalline positive electrode material and the grain boundaries within the particles through infiltration at high temperature.

[0012] The present invention is achieved through the following technical solutions:

[0013] A composite polycrystalline positive electrode material is prepared by infiltrating and coating a polycrystalline positive electrode material with a halide solid electrolyte, wherein the halide solid electrolyte includes one or more of Li-Ta-O-Cl, Li-Nb-O-Cl, Li-Zr-O-Cl, and Li-Al-O-Cl; the polycrystalline positive electrode material is layered LiCoO2, ternary layered oxide LiNi x Co y Mn 1−x−y O2, ternary layered oxide LiNi x Co y Al 1−x−y O2, olivine-type LiFePO4, spinel-type LiMn2O4, spinel-type LiMnO2, spinel-type LiNiO2, LiNi 0.5 Mn 1.5O4, xLi2MnO3·(1−x) LiMO2, Li 1+x M 1−x One or more of O2, lithium-rich layered positive electrode, and transition metal oxide materials, wherein M=Ni, Co, Mn.

[0014] The oxyhalide solid electrolyte is Li-Al-O-Cl. The mass proportion of polycrystalline positive electrode material is 80%-98%, and the mass proportion of oxyhalide solid electrolyte is 2%-20%.

[0015] An electrode sheet is prepared from the positive electrode material as described above.

[0016] The electrode sheet is made from a cathode material, a solid electrolyte, and a conductive agent. The cathode material accounts for 60%-85% by weight, the solid electrolyte for 15%-40%, and the conductive agent for 0-5%. The mixed cathode material is evenly spread throughout the solid-state battery mold and maintained at a pressure of 3 tons for 1-3 minutes to produce a cathode sheet that can be directly used in all-solid-state batteries.

[0017] In the electrode sheet, the solid electrolyte includes at least one of a sulfide solid electrolyte, a halide solid electrolyte, and an oxide solid electrolyte. The conductive agent material includes one or more of conductive carbon black (SP), graphite, carbon fiber (VGCF), carbon nanotubes (CNTs), and graphene (GN).

[0018] An all-solid-state battery is prepared by including the electrode sheet mentioned above.

[0019] As described above, the preparation method of the positive electrode material is to mix the polycrystalline positive electrode material with the halide oxide electrolyte, sinter, cool, and refine the mixture. The sintering method is specifically to mix the mixture under the protection of an inert atmosphere, with a sintering temperature of 200-500°C and a sintering time of 6-12 hours. The mixing method is ball milling or hand milling. During the ball milling process, the ball-to-material ratio is 30:1, the rotation speed is 200-400 rpm, and the ball milling time is 1-2 hours. During the hand milling process, the material is ground in a mortar for 30 minutes. The refining process is ball milling or hand milling. During the ball milling process, the ball-to-material ratio is 30:1, the rotation speed is 200-400 rpm, and the ball milling time is 1-2 hours. During the hand milling process, the material is ground in a mortar for 30 minutes.

[0020] The present invention introduces a halide oxide solid electrolyte of a specific composition and adopts a penetration-coating synergistic strategy to modify the polycrystalline positive electrode material to achieve simultaneous effective and uniform coating on the particle surface and internal grain boundaries. Compared with single-crystal positive electrode materials, polycrystalline materials are prone to structural fractures due to volume expansion and stress concentration during the charge and discharge process due to the presence of a large number of grain boundaries between their particles, which in turn leads to capacity decay and decreased cycle life. Although polycrystalline materials have certain advantages in compaction performance, due to their high grain boundary activity and relatively poor chemical stability, it is difficult to directly work stably in all-solid-state batteries for a long time, resulting in limited improvement in their actual energy density. The halide oxide electrolyte used in the present invention exhibits excellent ionic conductivity and strong interfacial wettability at room temperature. It can penetrate into the internal grain boundary region of the polycrystalline positive electrode without inducing side reactions, thereby achieving deep interface construction and stabilization. The permeable coating effectively blocks direct contact between the electrolyte and the highly active grain boundaries in the positive electrode and balances the mechanical stress during charging and discharging, reducing the possibility of side reactions while significantly inhibiting particle breakage and structural pulverization, thereby improving the structural integrity and cycle stability of the material.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] The present invention uses a specific halide oxide electrolyte to infiltrate and coat the polycrystalline positive electrode material, thereby achieving uniform coating of the surface of the polycrystalline positive electrode material and the grain boundaries within the particles, and realizing capacity utilization inside the polycrystalline positive electrode material particles; effectively blocking direct contact between the electrolyte and the highly active grain boundaries in the positive electrode, reducing interfacial side reactions; acting as a buffer interface, coordinating the mechanical stress during the charge and discharge process, and significantly inhibiting particle breakage and structural pulverization; through the coating effect of the halide oxide with high ionic conductivity, regulating the ion transport inside and in the gaps of the polycrystalline positive electrode material particles, reducing the interfacial impedance, and achieving an increase in energy density, the invention has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0024] Figure 1 Schematic diagram of the process of preparing the positive electrode material according to an embodiment of the present invention.

[0025] Figure 2 This is the charge and discharge curve of the first cycle of Example 1.

[0026] Figure 3 This is the charge and discharge curve of the first cycle of Example 2.

[0027] Figure 4 This is the electrochemical curve of Example 3.

[0028] Figure 5 This is the first cycle charge and discharge curve of comparative example 1.

[0029] Figure 6 This is the first cycle charge and discharge curve of comparative example 2.

[0030] Figure 7 SEM images of (a) Comparative Example, (b) Example 1, and (c) Example 2 DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0032] Example 1

[0033] Preparation method of the positive electrode material in this embodiment:

[0034] Step 1: Polycrystalline positive electrode material LiNi 0.8 Co 0.1 Mn 0.1 O2 and halide oxide electrolyte Li-Al-O-Cl were mixed in a mass ratio of 9:1 and hand-grinded in a mortar for 30 min to achieve uniform mixing.

[0035] Step 2: Mix the LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li-Al-O-Cl composite polycrystalline positive electrode was placed in a crucible, sintered at 200°C for 9 hours in a muffle furnace protected by an inert atmosphere, and cooled with the furnace.

[0036] Step 3: Sinter the LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li-Al-O-Cl composite polycrystalline positive electrode was put into a mortar and hand-ground to obtain a polycrystalline LiNi uniformly coated with Li-Al-O-Cl. 0.8 Co 0.1 Mn 0.1 O2 positive electrode material.

[0037] Assembly method of the all-solid-state battery in this embodiment:

[0038] LiNi 0.8 Co 0.1 Mn 0.1The O2-Li-Al-O-Cl composite polycrystalline cathode, Li6PS5Cl, and Super P were ground in a mortar at a ratio of 70:28:2 for 10 minutes to achieve a uniform mixture. The mixed cathode material was evenly spread throughout a solid-state battery mold and maintained at a pressure of 3 tons for 3 minutes to produce a positive electrode sheet that can be directly used in all-solid-state batteries. The resulting positive electrode sheet was assembled with the Li6PS5Cl electrolyte layer and the Li-In alloy anode to form the all-solid-state battery used in this example.

[0039] The all-solid-state battery in this embodiment was first activated by charging and discharging for three cycles at a rate of 0.1C and a cut-off voltage of 2.5 V to 4.3 V, and then subjected to a charge and discharge cycle test at a rate of 0.3C and a cut-off voltage of 2.5 V to 4.3 V. Figure 1 The infiltration and coating process of halide oxide electrolyte on polycrystalline cathode materials is demonstrated. Figure 2 The coated polycrystalline ternary cathode can deliver 142.5 mAh g in the first cycle. - 1 The capacity, through Figure 7 (b) shows that the electron microscope photo shows that Figure 7 (a) The uncoated polycrystalline positive electrode material. Coating can make the electrolyte evenly cover the particle surface and grain boundaries.

[0040] Example 2

[0041] Step 1: Polycrystalline positive electrode material LiNi 0.8 Co 0.1 Mn 0.1 O2 and halide oxide electrolyte Li-Al-O-Cl were mixed in a mass ratio of 9.5:0.5 and hand-grinded in a mortar for 30 min to achieve uniform mixing.

[0042] Step 2: Mix the LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li-Al-O-Cl composite polycrystalline positive electrode was placed in a crucible, sintered at 250°C for 6 hours in a muffle furnace protected by an inert atmosphere, and cooled with the furnace.

[0043] Step 3: Sinter the LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li-Al-O-Cl composite polycrystalline positive electrode was put into a mortar and hand-ground to obtain a polycrystalline LiNi uniformly coated with Li-Al-O-Cl. 0.8 Co 0.1 Mn 0.1 O2 positive electrode material.

[0044] Assembly method of the all-solid-state battery in this embodiment:

[0045] LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li-Al-O-Cl composite polycrystalline cathode, Li6PS5Cl, and Super P were ground in a mortar at a ratio of 70:28:2 for 10 minutes to achieve a uniform mixture. The mixed cathode material was evenly spread throughout a solid-state battery mold and maintained at a pressure of 3 tons for 3 minutes to produce a positive electrode sheet that can be directly used in all-solid-state batteries. The resulting positive electrode sheet was assembled with the Li6PS5Cl electrolyte layer and the Li-In alloy anode to form the all-solid-state battery used in this example.

[0046] The all-solid-state battery in this embodiment was first activated by charging and discharging for 3 cycles at a rate of 0.1C and a cut-off voltage of 2.5 V to 4.3 V, and then subjected to a charge and discharge cycle test at a rate of 0.3C and a cut-off voltage of 2.5 V to 4.3 V. Figure 3 As shown, the coated polycrystalline ternary cathode can deliver 128.6 mAh g in the first cycle. - 1 The capacity, through Figure 7 (c) shows that the electron microscope photo shows that Figure 7 (a) The uncoated polycrystalline positive electrode material. Coating can make the electrolyte evenly cover the particle surface and grain boundaries.

[0047] Example 3

[0048] Preparation method of composite positive electrode material in this embodiment:

[0049] Step 1: Polycrystalline cathode material Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O2 and halide oxide electrolyte Li-Al-O-Cl were mixed in a mass ratio of 9:1 and hand-grinded in a mortar for 30 min to achieve uniform mixing.

[0050] Step 2: Mix the Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 The O2-Li-Al-O-Cl composite polycrystalline positive electrode was placed in a crucible, sintered at 230°C for 8 hours in a muffle furnace protected by an inert atmosphere, and cooled with the furnace.

[0051] Step 3: Sinter the Li 1.2 Mn 0.54 Co 0.13 Ni 0.13The O2-Li-Al-O-Cl composite polycrystalline positive electrode was put into a mortar and ground by hand to obtain a polycrystalline Li uniformly coated with Li-Al-O-Cl. 1.2 Mn 0.54 Co 0.13 Ni 0.13 O2 positive electrode material.

[0052] Assembly method of the all-solid-state battery in this embodiment:

[0053] Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 The O2-Li-Al-O-Cl composite polycrystalline cathode, Li6PS5Cl, and Super P were ground in a mortar at a ratio of 65:30:5 for 10 minutes to achieve a uniform mixture. The mixed cathode material was evenly spread throughout a solid-state battery mold and maintained at a pressure of 3 tons for 3 minutes to produce a positive electrode sheet that can be directly used in all-solid-state batteries. The resulting positive electrode sheet was assembled with the Li6PS5Cl electrolyte layer and the Li-In alloy anode to form the all-solid-state battery used in this example.

[0054] The all-solid-state battery in this embodiment was first activated by charging and discharging for 3 cycles at a rate of 0.1C and a cut-off voltage of 2.5 V to 4.8 V, and then subjected to a charge and discharge cycle test at a rate of 0.3C and a cut-off voltage of 2.5 V to 4.8 V. The test results are shown in Figure 2. Figure 4 As shown, the coated polycrystalline ternary cathode can exert a capacity of 199.8 mAh g-1 in the first cycle.

[0055] Comparative Example 1

[0056] Uncoated polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 The O2 cathode, Li6PS5Cl, and Super P were ground in a mortar at a ratio of 70:28:2 for 10 minutes to achieve a uniform mixture. The mixed cathode material was evenly spread throughout a solid-state battery mold and maintained at a pressure of 3 tons for 3 minutes to produce a positive electrode sheet that can be directly used in all-solid-state batteries. The resulting positive electrode sheet was assembled with the Li6PS5Cl electrolyte layer and the Li-In alloy anode to form the all-solid-state battery used in this example.

[0057] The all-solid-state battery in this comparative example was first activated by charging and discharging for 3 cycles at a rate of 0.1C and a cut-off voltage of 2.5 V to 4.3 V, and then subjected to a charge and discharge cycle test at a rate of 0.3C and a cut-off voltage of 2.5 V to 4.3 V. Figure 5As shown, the coated polycrystalline ternary cathode can only produce 91.7 mAh g in the first cycle. - 1 Compared with Examples 1-3, the coated polycrystalline positive electrode material can achieve higher capacity, thereby effectively improving the energy density of the entire battery.

[0058] Comparative Example 2

[0059] Preparation method of composite positive electrode material in this embodiment:

[0060] Step 1: Polycrystalline positive electrode material LiNi 0.8 Co 0.1 Mn 0.1 O2 and halide electrolyte Li3YCl6 were mixed in a mass ratio of 9.5:0.5 and hand-grinded in a mortar for 30 minutes to achieve uniform mixing.

[0061] Step 2: Mix the LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li3YCl6 composite polycrystalline positive electrode was placed in a crucible, sintered at 250°C for 6 hours in a muffle furnace protected by an inert atmosphere, and cooled with the furnace.

[0062] Step 3: Sinter the LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li3YCl6 composite polycrystalline positive electrode was put into a mortar and ground by hand to obtain a polycrystalline LiNi uniformly coated with Li3YCl6. 0.8 Co 0.1 Mn 0.1 O2 positive electrode material.

[0063] (3) Assembly method of the all-solid-state battery in this embodiment:

[0064] LiNi 0.8 Co 0.1 Mn 0.1 The O2-Li3YCl6 composite polycrystalline cathode, Li6PS5Cl, and Super P were ground in a mortar at a ratio of 70:28:2 for 10 minutes to achieve a uniform mixture. The mixed cathode material was evenly spread throughout a solid-state battery mold and maintained at a pressure of 3 tons for 3 minutes to produce a cathode sheet that can be directly used in all-solid-state batteries. The resulting cathode sheet was assembled with the Li6PS5Cl electrolyte layer and the Li-In alloy anode into the all-solid-state battery used in this example.

[0065] The all-solid-state battery in this embodiment was first activated by charging and discharging for 3 cycles at a rate of 0.1C and a cut-off voltage of 2.5 V to 4.3 V, and then subjected to a charge and discharge cycle test at a rate of 0.3C and a cut-off voltage of 2.5 V to 4.3 V. Figure 6 As shown, the coated polycrystalline ternary cathode only exerted 104.25 mAh g in the first cycle. -1 Commonly used halide electrolytes are melted under the premise of ensuring the structural stability of the polycrystalline positive electrode material. This makes it impossible to achieve effective coating of the halide electrolyte on the grain boundaries within the polycrystalline positive electrode, resulting in increased side reactions and mechanical stress at the polycrystalline grain boundaries, particle breakage and structural pulverization during the cycle, and failure to effectively utilize the capacity.

[0066] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite polycrystalline positive electrode material, characterized in that: It is prepared by infiltration and coating of polycrystalline positive electrode materials with oxyhalide solid electrolytes, the oxyhalide solid electrolytes include one or more of Li-Ta-O-Cl, Li-Nb-O-Cl, Li-Zr-O-Cl, Li-Al-O-Cl; the polycrystalline positive electrode materials are layered LiCoO2, ternary layered oxide LiNi x Co y Mn 1−x−y O2, ternary layered oxide LiNi x Co y Al 1−x−y O2, olivine-type LiFePO4, spinel-type LiMn2O4, spinel-type LiMnO2, spinel-type LiNiO2, LiNi 0.5 Mn 1.5 O4, xLi2MnO3·(1−x) LiMO2, Li 1+x M 1−x One or more of O2, lithium-rich layered positive electrode, and transition metal oxide materials, wherein M=Ni, Co, Mn.

2. The positive electrode material according to claim 1, characterized in that The oxyhalide solid electrolyte is Li-Al-O-Cl.

3. The positive electrode material according to claim 1, characterized in that The mass proportion of polycrystalline positive electrode materials is 80%-98%, and the mass proportion of halide oxide solid electrolyte is 2%-20%.

4. An electrode sheet, characterized in that: The positive electrode material is prepared from the positive electrode material according to any one of claims 1 to 3.

5. The electrode sheet according to claim 4, characterized in that It is prepared from positive electrode material, solid electrolyte and conductive agent, with the mass proportion of positive electrode material being 60%-85%, the mass proportion of solid electrolyte being 15%-40%, and the mass proportion of conductive agent being 0-5%.

6. An all-solid-state battery, characterized in that: The method is prepared by comprising the electrode sheet according to claim 4.

7. The method for preparing a positive electrode material according to any one of claims 1 to 3, characterized in that: The polycrystalline positive electrode material is mixed with the halide oxide electrolyte, sintered, cooled and refined. The sintering method is specifically to mix the mixture under the protection of an inert atmosphere, the sintering temperature is 200-500°C, and the sintering time is 6-12h.

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