Solid-state battery positive electrode and preparation method and application thereof

Abstract

The invention provides a solid-state battery positive electrode and a preparation method and application thereof, and relates to the technical field of solid-state batteries. Specifically, the method comprises the following steps: mixing a positive electrode active material and a solid electrolyte, and carrying out mechanical ball milling treatment to obtain composite powder; preparing the positive electrode for the solid-state battery from a material containing the composite powder; wherein in the mechanical ball milling treatment, the mass ratio of the positive electrode active material to the solid electrolyte is (30-40): (60-70), and the ball-material ratio is (20-50): 1. The defect that the capacity utilization rate of an electrode active material is low when the all-solid-state battery is high in surface load can be effectively overcome, and the excellent performance of the solid-state positive electrode in the ion transmission capacity and the capacity utilization rate can be achieved by limiting the technological method and parameters of mechanical ball milling.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a solid-state battery positive electrode and a preparation method and application thereof. Background Art

[0002] As a simple and efficient energy storage system, lithium-ion batteries have received significant attention in all aspects of modern energy technology development. However, the organic electrolytes in traditional liquid batteries have drawbacks such as environmental unfriendliness and flammability. Furthermore, there are safety concerns such as lithium dendrites penetrating the separator, causing internal short circuits in the battery, which in turn can lead to flammability and explosion. All-solid-state batteries, which replace the electrolyte and separator in traditional lithium-ion batteries with solid-state electrolytes, can effectively circumvent these issues, offering high safety and energy density. Solid-state batteries are expected to become a key technology in the next generation of secondary batteries.

[0003] Compared with traditional liquid batteries, in which the lithium ions transferred from the electrode material can directly enter the electrolyte and be transferred between the positive and negative electrodes after the electrolyte fully infiltrates the electrode material, for all-solid-state batteries, the solid electrolyte does not have the fluidity and wettability of the electrolyte, so the lithium ions transferred from the electrode material cannot directly enter the solid electrolyte layer. Therefore, it is necessary to add a certain proportion of solid electrolyte powder to the electrode material as a medium for the transfer of lithium ions between the electrode material and the electrolyte layer. In this field, the powder obtained by evenly mixing the electrode material and the electrolyte is usually called a composite electrode, and is directly used as the electrode of the solid-state battery. However, the contact mode between the active material particles and the electrolyte particles in the composite electrode is a "point-to-point" contact between solid and solid. Compared with the transmission mode of liquid batteries, the transmission path of ions in the composite electrode of solid-state batteries is more tortuous.

[0004] As the process requirements for battery energy density gradually increase, the use of positive electrode active materials with high operating voltage and high theoretical specific capacity alone can no longer meet functional requirements. It is also necessary to further increase the amount of composite electrodes to ensure the high areal capacity density of solid-state batteries. However, as the amount of composite electrodes increases, the thickness of the composite electrodes also increases significantly, which makes the path for ions in the active materials in the composite electrodes to be transferred to the electrolyte layer longer. Therefore, when the amount of composite electrodes is increased, the capacity utilization rate of the active materials is greatly reduced due to the insufficient ion transmission capacity of the composite electrodes.

[0005] In addition, commercial ternary transition metal oxides, used as positive electrode active materials in solid-state batteries, experience severe volume changes and cracking between primary particles during charge and discharge. Since the electrolyte in the composite electrode cannot fill the cracks between primary particles, nor can it fill the gaps formed between the active material and the electrolyte after the volume change, this further reduces the ion transport performance within the composite electrode at high areal loadings in solid-state batteries. Therefore, optimizing the composite method between the active material and the electrolyte in the composite electrode will be of great significance for improving the capacity utilization of the active material when high composite electrode dosages are used.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The first purpose of the present invention is to provide a method for preparing a solid-state battery positive electrode, which is mainly used to solve the defect of low capacity utilization of electrode active materials when the all-solid-state battery has a high surface loading; the present invention introduces a mechanical ball milling process to prepare a solid-state positive electrode with high ion transmission capability and high capacity utilization.

[0008] A second object of the present invention is to provide a solid-state battery positive electrode.

[0009] The third object of the present invention is to provide an all-solid-state battery.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: A method for preparing a positive electrode for a solid-state battery comprises the following steps: mixing a positive electrode active material and a solid electrolyte, and subjecting the mixture to mechanical ball milling to obtain a composite powder; and preparing a material containing the composite powder to obtain a positive electrode for a solid-state battery. Wherein, in the mechanical ball milling process, the mass ratio of the positive electrode active material to the solid electrolyte is (30-40): (60-70), and the ball-to-material ratio is (20-50):1.

[0011] Preferably, the positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide or lithium-rich manganese-based positive electrode material; Preferably, the solid electrolyte includes at least one of a halide solid electrolyte or a sulfide solid electrolyte.

[0012] Preferably, the mechanical ball milling treatment time is 1 hour to 5 hours, and the rotation speed of the mechanical ball milling treatment is 100 rpm to 500 rpm.

[0013] Preferably, the mechanical ball milling treatment comprises the following steps: placing the positive electrode active material, the solid electrolyte and grinding balls into a ball milling jar, and placing the jar in a ball mill for grinding.

[0014] More preferably, the material of the grinding balls and / or the grinding jar includes at least one of stainless steel, cemented carbide or zirconium oxide; further preferably, the material of the grinding balls and the grinding jar is zirconium oxide.

[0015] More preferably, the diameter of the grinding balls is 4 mm to 6 mm.

[0016] More preferably, the ball mill is a planetary ball mill; the orbital speed of the planetary ball mill is 100 rpm to 500 rpm, the rotational speed is 100 rpm to 500 rpm, and the speed ratio of the orbital speed to the rotational speed is 1:(0.8 to 1.2).

[0017] Preferably, the preparation method comprises the following steps: placing the material containing the composite powder in a mold, applying an external pressure of 3t~6t to both sides of the mold, and continuously applying pressure for 3s~8s to obtain the sheet-shaped positive electrode for the solid-state battery.

[0018] A solid-state battery positive electrode is prepared using the solid-state battery positive electrode preparation method.

[0019] An all-solid-state battery comprises the solid-state battery positive electrode.

[0020] The present invention processes the cathode active material and solid electrolyte through mechanical ball milling to produce a solid-state battery cathode with high ion transport capability and high capacity utilization. Compared with the prior art, the present invention has the following advantages: On the one hand, the present invention places active electrode materials and electrolytes in appropriate proportions into a high-energy ball mill for mechanical ball milling. The energy provided by the mechanical ball milling can grind secondary particles of micron-sized particles into submicron-sized primary particles, avoiding cracking between primary particles during electrochemical testing, thereby improving the capacity utilization of the active material.

[0021] On the other hand, solid electrolytes often have a "softer" texture than positive electrode active materials. After the mechanical ball milling process, the electrolyte will be evenly wrapped on the surface of the active electrode material, achieving perfect fit between the electrolyte and the positive electrode active material in the composite electrode, avoiding the "point-to-point" contact between the positive electrode active material and the solid electrolyte in conventional solid-state electrodes, thereby effectively promoting the rapid transmission of ions at the interface.

[0022] On the other hand, the above-mentioned perfectly fitted solid-state electrode has a high density, so that the thickness of the electrode remains relatively thin when the amount of active material is increased, and it can resist the gaps left at the interface after the volume change of the active material, greatly shortening the ion transmission path in the solid-state electrode and ensuring the integrity of the electrode structure. At the same time, even if the amount of active material is not increased, the thickness of the solid-state positive electrode obtained by the present invention will be thinner than that of the conventional preparation process, which can shorten the transmission path of lithium ions in the electrode. Thus, the present invention can achieve a high capacity utilization rate of the electrode active material and realize the use of a high areal capacity density. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A process flow chart of the present invention is provided; Figure 2 Provided is a graph of the first charge and discharge test of Example 1 of the present invention; Figure 3 Provided is a graph of the first charge and discharge test of Comparative Example 2 of the present invention; Figure 4 Provided is a graph of the first charge and discharge test of Comparative Example 3 of the present invention; Figure 5 Provided is a graph of the first charge and discharge test of Comparative Example 4 of the present invention; Figure 6 A curve diagram of the first charge and discharge test of Comparative Example 5 of the present invention is provided. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. However, it will be understood by those skilled in the art that the following embodiments are only some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially. In addition, the terms "first", "second" and "third" are only used for descriptive purposes and are not to be construed as indicating or implying relative importance.

[0026] A first aspect of the present invention is to provide a method for preparing a positive electrode of a solid-state battery.

[0027] The preparation method mainly includes the following steps: mixing a positive electrode active material and a solid electrolyte, performing mechanical ball milling treatment to obtain a composite powder; preparing a material containing the composite powder to obtain a positive electrode for a solid-state battery; wherein, in the mechanical ball milling treatment, the mass ratio of the positive electrode active material to the solid electrolyte is (30~40): (60~70), and the ball-to-material ratio is (20~50):1.

[0028] The present invention processes the positive electrode active material and the solid electrolyte by mechanical ball milling to prepare a solid-state battery positive electrode with high ion transport capability and high capacity utilization, such as Figure 1 The figure provides a process flow diagram of the present invention.

[0029] As an optional embodiment, the mass ratio of the positive electrode active material to the solid electrolyte includes but is not limited to any one of 30:70, 31:69, 32:68, 33:67, 34:66, 35:65, 36:64, 37:63, 38:62, 39:61, and 40:60, or a ratio range consisting of any two of them.

[0030] It is worth noting that during the mechanical ball milling process, the ratio of the positive electrode active material to the solid electrolyte must be controlled within an appropriate range to ensure that the solid electrolyte is in sufficient contact with the positive electrode active material.

[0031] As an optional embodiment, the ball-to-material ratio includes but is not limited to any one of 20:1, 22.5:1, 25:1, 27.5:1, 30:1, 32.5:1, 35:1, 37.5:1, 40:1, 42.5:1, 45:1, 47.5:1, and 50:1, or a ratio range consisting of any two of them.

[0032] It is worth noting that in the present invention, it is necessary to reasonably control the ball-to-material ratio to provide sufficient pressure on the grinding material, and then provide sufficient energy to achieve the crushing and refinement of the material; at the same time, while taking into account the grinding efficiency, a ball milling process that conforms to the crushing mechanism preset in the present invention is obtained.

[0033] As a preferred embodiment, the positive electrode active material includes at least one of a transition metal oxide positive electrode material, a spinel structure positive electrode material, an olivine structure positive electrode material, a lithium-rich manganese-based positive electrode material, and a polyanion positive electrode material, and more preferably a layered transition metal oxide positive electrode material, including but not limited to lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMnO2), lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O2), lithium nickel cobalt aluminum oxide (LiNi x Co y Al 1-x- y O2), or more preferably, a lithium-rich manganese-based positive electrode material (xLi2MnO3·(1-x)LiMO2, M=Ni / Co / Mn, etc.)

[0034] As a preferred embodiment, the solid electrolyte includes at least one of a halide solid electrolyte or a sulfide solid electrolyte; the halide solid electrolyte includes at least one of Li3InX6 or Li2ZrX6, X is selected from at least one of Cl, Br, and I; the sulfide solid electrolyte includes Li6PS5Cl, Li3PS4, Li7P3S 11 、Li 10 GeP2S 12 、Li 10 SnP2S 12 At least one of .

[0035] As a preferred embodiment, the mechanical ball milling treatment time is 1 hour to 5 hours, and the mechanical ball milling treatment speed is 100 rpm to 500 rpm. In some optional embodiments, the mechanical ball milling treatment time includes but is not limited to any one of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 (hours) or a numerical range consisting of any two of them, and the mechanical ball milling treatment speed includes but is not limited to any one of 100, 150, 200, 250, 300, 350, 400, 450, and 500 (rpm) or a numerical range consisting of any two of them.

[0036] It is worth noting that in the present invention, only mechanical ball milling can be used for processing, and manual grinding cannot be used as a substitute; apart from considerations of industrial production efficiency, manual grinding makes it difficult to ensure that the material is subjected to uniform force in all directions, and defects such as uneven mixing or wide particle size distribution are very likely to occur; at the same time, the collision frequency and contact area introduced by mechanical ball milling can achieve the coating of the positive electrode active material by the solid electrolyte as expected by the present invention, thereby achieving the technical effect of improving the capacity utilization of the active material in the present invention.

[0037] As a preferred embodiment, the mechanical ball milling treatment comprises the following steps: placing the positive electrode active material, the solid electrolyte and grinding balls into a ball milling jar, and placing the jar in a ball mill for grinding.

[0038] As a preferred embodiment, the ball mill is a high-energy ball mill. It is worth noting that by replacing conventional ball mill containers with high-energy ball mills, higher energy input and stronger grinding effects can be achieved, thereby achieving fine grinding of secondary particles and obtaining submicron or even nanometer-level primary particles.

[0039] As a more preferred embodiment, the material of the grinding balls and / or the high-energy grinding jar includes at least one of stainless steel, cemented carbide or zirconium oxide; as a more preferred embodiment, the grinding balls are made of zirconium oxide and the grinding jar is also made of zirconium oxide.

[0040] As a more preferred embodiment, the diameter of the grinding balls is 4 mm to 6 mm, more preferably 5 mm in diameter.

[0041] As a more preferred embodiment, the ball mill is a planetary ball mill, wherein the orbital speed of the planetary ball mill is 100 rpm~500 rpm, the rotation speed is 100 rpm~500 rpm, and the speed ratio of the orbital speed to the rotation speed is 1:(0.8~1.2). Further preferably, the speed ratio of the orbital speed to the rotation speed is 1:1.

[0042] As a preferred embodiment, the mechanical ball milling treatment is carried out in a protective gas atmosphere, and the protective gas includes but is not limited to one or more of nitrogen, helium, neon or argon.

[0043] The present invention also involves the step of preparing a material containing the composite powder into a solid-state battery positive electrode. It is understandable that the present invention does not focus on limiting the process method or specific process parameters in this process.

[0044] As a preferred embodiment, the method for preparing the positive electrode for the solid-state battery includes: placing the material containing the composite powder in a mold, applying an external pressure of 3t~6t on both sides of the mold, and continuously applying pressure for 3s~8s to obtain the sheet-shaped positive electrode for the solid-state battery.

[0045] As a preferred embodiment, the "material containing the composite powder" includes the following components: the composite powder, as well as a conductive agent, a binder and a current collector; in this embodiment, its preparation method mainly involves: preparing a mixture of the composite powder, the conductive agent and the binder, and compounding the mixture with the current collector through a dry process to obtain the solid-state battery positive electrode.

[0046] The present invention does not impose strict restrictions on the types and ratios of the conductive agent, binder, and current collector used in the above embodiments. Alternatively, in some non-preferred embodiments, the "material comprising the composite powder" may consist solely of the composite powder; the "material comprising the composite powder" may also include a positive electrode active material and / or a solid electrolyte, meaning these two components are not added solely through the mechanical milling process.

[0047] The second aspect of the present invention is to provide a solid-state battery positive electrode obtained by the preparation method of the solid-state battery positive electrode as described in the first aspect.

[0048] The third aspect of the present invention is to provide an all-solid-state battery, comprising the solid-state battery positive electrode as described in the second aspect. It is understood that, in addition to the solid-state battery positive electrode, the all-solid-state battery should include a negative electrode, an electrolyte, and other necessary or non-essential functional elements or packaging components, etc., which can be arbitrarily selected and combined by those skilled in the art; when the solid-state battery positive electrode described in the present invention is included in the all-solid-state battery, whether or not other solid-state positive electrodes are compounded in the all-solid-state battery, it can be regarded as an embodiment of the present invention.

[0049] Example 1 1) This example was carried out in a glove box filled with argon; solid electrolyte Li3InCl6 was mixed with commercial active electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2 is weighed at a mass ratio of 65:35 and then placed in a ball mill made of ZrO2.

[0050] 2) Add 5mm diameter ZrO2 balls to the ball mill and control the ball-to-material ratio so that the total mass of the balls added is 30 times the total mass of the materials added in the first step.

[0051] 3) Place the ball mill jar in a planetary ball mill and mill for 2 h at an orbital speed of 300 rpm and an axisymmetric speed of 300 rpm.

[0052] 4) After the ball milling is completed, the powder in the ball mill is scraped off to obtain the composite positive electrode material.

[0053] Example 2 The process is basically the same as Example 1, except that the ball-to-material ratio is controlled to be 20 in step 2).

[0054] Example 3 The process is basically the same as Example 1, except that the ball-to-material ratio is controlled to be 40 in step 2).

[0055] Example 4 The process is basically the same as Example 1, except that the ball milling time in step 3) is controlled to be 1 h.

[0056] Example 5 The process is basically the same as Example 1, except that the ball milling time in step 3) is controlled to be 4 h.

[0057] Example 6 The process is basically the same as Example 1, except that in step 3), the planetary ball mill is replaced by a high-speed ball mill, and the rotation speed is controlled to be 400 revolutions per minute for both revolution and rotation.

[0058] Comparative Example 1: Preparation of Ordinary Micron-Scale Cathode Materials 1) This comparative example was carried out in a glove box filled with argon; the solid electrolyte Li3InCl6 and the active electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2 was weighed in a mass ratio of 65:35 and then placed in an agate mortar.

[0059] 2) The mixed powder in the agate mortar was hand-grinded for 30 minutes to obtain the positive electrode material of this comparative example.

[0060] Comparative Example 2: Preparation of ordinary submicron cathode materials 1) This comparative example was carried out in a glove box filled with argon; the active electrode material LiNi 0.9 Co 0.05 Mn 0.05 O2 is placed in a ball mill jar made of ZrO2.

[0061] 2) Add 5mm diameter ZrO2 balls to the ball mill and control the ball-to-material ratio so that the total mass of the balls added is 30 times the mass of the material added in the first step.

[0062] 3) Place the ball mill jar in a planetary ball mill and mill for 2 h. The orbital and rotation speeds of the ball mill are both 200 rpm.

[0063] 4) After the ball milling is completed, the powder in the ball mill is scraped off to obtain submicron active electrode materials.

[0064] 5) The solid electrolyte Li3InCl6 and the material obtained in step 4) were weighed in a weight ratio of 65:35 and then placed in an agate mortar.

[0065] 6) The mixed powder in the agate mortar was hand-grinded for 30 minutes to obtain the positive electrode material of this comparative example.

[0066] Comparative Example 3 The method is basically the same as Example 1, except that the mass ratio in step 1) is replaced with 55:45.

[0067] Comparative Example 4 The process is basically the same as Example 1, except that the mass ratio in step 1) is replaced with 75:25.

[0068] Test example: Assembly and testing of all-solid-state batteries S1. 80 mg of Li6PS5Cl powder was placed into a 10 mm diameter PKKT all-solid-state mold. A pressure of 3 tons was applied to the upper and lower ends of the mold for 5 seconds to press the powder into a sheet-like electrolyte layer.

[0069] S2. Add 20 mg of the positive electrode material prepared in each embodiment and comparative example to one side of the electrolyte layer, ensuring that the distribution is as uniform as possible. Apply 5t pressure to the upper and lower ends of the mold for 5 seconds to obtain a sheet-like electrolyte-positive electrode composite layer.

[0070] S3. Stack the In sheet and Li sheet with a molar ratio of 3:1 together and cold press them at 10 MPa for 5 seconds to obtain a Li-In alloy negative electrode. Then use an 8mm punch to cut it, take a piece of the finished alloy negative electrode and place it on the other side of the electrolyte layer. Finally, apply 2t pressure at the upper and lower ends of the mold and maintain the pressure to obtain an all-solid-state battery for testing.

[0071] The battery assembly processes involved in S1 to S3 were all carried out in a glove box filled with Ar gas atmosphere.

[0072] S4. After the all-solid-state batteries corresponding to each embodiment or comparative example were allowed to rest for 1 minute, constant current charge and discharge tests were performed. Test parameters were as follows: operating voltage 2.1V-3.7V (vs Li-In), operating current 20 mA / g. The mass specific capacity and initial coulombic efficiency (ICE) values ​​of the positive electrode materials in each all-solid-state battery during the initial charge and discharge were measured and recorded in Table 1.

[0073] Table 1

[0074] In addition, if Figure 2 The first charge and discharge curve of Example 1 is shown in FIG. 1 ; it can be seen that the positive electrode active material provides a higher mass specific capacity at a high surface loading (20 mg), which exceeds 90% of the theoretical mass specific capacity; the all-solid-state battery uses this electrode to achieve a capacity of more than 3 mAh g -1 The areal capacity density of is 2.533 Å, which proves that the preparation process of the present invention is helpful to improve the capacity utilization of active materials in high areal loading all-solid-state batteries.

[0075] like Figure 3 The first charge and discharge curve of Comparative Example 1 is shown in FIG. Figure 4 The figure shows the first charge and discharge curve of Comparative Example 2; it can be seen that the preparation process of the present invention has better electrochemical performance than conventional grinding or manual grinding, and ordinary hand grinding mixing cannot achieve high capacity utilization of active materials.

[0076] like Figure 5 The first charge and discharge curve of Comparative Example 3 is shown in FIG. Figure 6 The figure shows the first charge and discharge curve of Comparative Example 4. It can be seen that the importance of defining the mass ratio of active material and solid electrolyte in the solid positive electrode of the present invention is significant. The ratio of active electrode material to electrolyte will also directly affect the capacity utilization of active material.

[0077] Although the present invention has been illustrated and described using specific embodiments, it should be appreciated that the above embodiments are merely intended to illustrate the technical solutions of the present invention rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and scope of the present invention. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a solid-state battery positive electrode, characterized in that: The method comprises the following steps: mixing a positive electrode active material and a solid electrolyte, and subjecting the mixture to mechanical ball milling to obtain a composite powder; and preparing a material containing the composite powder to obtain a positive electrode for a solid-state battery. Wherein, in the mechanical ball milling process, the mass ratio of the positive electrode active material to the solid electrolyte is (30-40): (60-70), and the ball-to-material ratio is (20-50):

1.

2. The method for preparing a solid-state battery positive electrode according to claim 1, characterized in that: The positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide or lithium-rich manganese-based positive electrode material; And / or, the solid electrolyte includes at least one of a halide solid electrolyte or a sulfide solid electrolyte.

3. The method for preparing a solid-state battery positive electrode according to claim 1, characterized in that: The time of the mechanical ball milling treatment is 1 hour to 5 hours, and the rotation speed of the mechanical ball milling treatment is 100 rpm to 500 rpm.

4. The method for preparing a solid-state battery positive electrode according to claim 1, characterized in that: The mechanical ball milling treatment comprises the following steps: placing the positive electrode active material, the solid electrolyte and grinding balls into a ball milling jar, and placing the jar in a ball mill for grinding.

5. The method for preparing a solid-state battery positive electrode according to claim 4, characterized in that: The grinding balls and / or the grinding jar are made of at least one of stainless steel, cemented carbide or zirconium oxide; Preferably, the grinding balls and the grinding jar are made of zirconium oxide.

6. The method for preparing a solid-state battery positive electrode according to claim 4, characterized in that: The diameter of the grinding balls is 4 mm to 6 mm.

7. The method for preparing a solid-state battery positive electrode according to claim 4, characterized in that: The ball mill is a planetary ball mill; The planetary ball mill has an orbital speed of 100 rpm to 500 rpm, an autorotation speed of 100 rpm to 500 rpm, and a speed ratio of the orbital speed to the autorotation speed of 1:(0.8 to 1.2).

8. The method for preparing a solid-state battery positive electrode according to claim 1, characterized in that: The steps include: The material containing the composite powder is placed in a mold, and an external pressure of 3t to 6t is applied to both sides of the mold. The pressure is continuously applied for 3s to 8s to obtain the sheet-shaped positive electrode for the solid-state battery.

9. A solid-state battery positive electrode, characterized in that: It is prepared by the method for preparing a solid-state battery positive electrode according to any one of claims 1 to 8.

10. An all-solid-state battery, characterized in that: Comprising the solid-state battery positive electrode as described in claim 9.

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