High-specific-energy lithium-rich manganese-based positive electrode slurry for solid-state battery, and preparation method and application thereof

Abstract

The invention relates to a composite positive electrode film in a lithium ion battery, in particular to high-specific-energy lithium-rich manganese-based positive electrode slurry for a solid-state battery as well as a preparation method and application of the high-specific-energy lithium-rich manganese-based positive electrode slurry. The slurry comprises a lithium-rich manganese-based composite positive electrode material and a binder solution, wherein the lithium-rich manganese-based composite positive electrode material comprises a lithium-rich manganese-based positive electrode active material, a gas-phase modified sulfide electrolyte and a carbon-based conductive agent. The strategy of synergistic application of sulfide electrolyte gas-phase modification and low-polarity solvent liquid-phase coating provided by the invention solves the problem of solvent sensitivity in preparation of the sulfide all-solid-state battery composite positive electrode, and the method realizes uniform dispersion and good contact of all components in the composite positive electrode and improves the stability of the sulfide all-solid-state battery composite positive electrode. The interface stability among different components is improved; and the scheme has remarkable application potential and has important significance in promoting the development of high-specific-energy sulfide all-solid-state batteries.

Description

Technical Field

[0001] This invention relates to composite cathode films in lithium-ion batteries, specifically to a high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries are widely used in consumer electronics, electric vehicles, and smart grids due to their superior energy density, cycle life, and low self-discharge. Currently, solid-state lithium batteries, characterized by solid electrolytes, offer both high specific energy and high safety, making them a key route for replacing traditional liquid lithium-ion batteries and achieving technological advancements in electrochemical energy storage. Among solid electrolytes represented by oxides, halides, and sulfides, sulfide solid electrolytes possess higher ionic conductivity and lower Young's modulus, enabling rapid lithium-ion transport while also exhibiting certain rigidity and flexibility, facilitating good interfacial contact between electrode materials and the solid electrolyte. Therefore, solid-state lithium battery technology based on sulfide solid electrolytes has attracted significant attention from numerous research institutions and related companies. On the one hand, as the primary source of lithium ions in solid-state lithium batteries, the type, structure, and electrochemical performance of the cathode material largely determine the energy density, cycle performance, and manufacturing cost of the solid-state lithium battery. Currently, commercially available cathode materials such as LiCoO2, LiFePO4, and NCM generally suffer from low specific capacity (≤200 mAh / g), while lithium-rich manganese-based cathode materials... x Li2MnO3·(1 -x LiTMO2 (TM = Ni, Mn, Co) is effective not only at low voltages (≤4.4V, vs. Li) + Li provides charge / discharge capacity through the redox reaction of transition metal ions and at high voltages (≥4.4V, vs. Li). +The oxygen anion (Li) also participates in the reversible reaction and provides additional charge / discharge capacity. Therefore, lithium-rich manganese-based cathode materials have higher discharge specific capacity (>250 mAh / g) and energy density (~1000 Wh / Kg) than traditional cathodes. Furthermore, the high manganese content of lithium-rich manganese-based cathode materials also gives them a low-cost advantage. On the other hand, as a key component of sulfide solid-state lithium batteries, composite cathode materials composed of cathode active materials, sulfide electrolytes, and conductive agents are key factors affecting the electrochemical performance of solid-state lithium batteries, such as capacity and cycle life. Therefore, developing lithium-rich manganese-based composite cathode materials based on sulfide solid electrolytes has significant research value and application prospects. Composite cathodes can be divided into two categories based on their state: composite cathode powder and composite cathode film. Composite cathode powder is often used in laboratory mold batteries and focuses on research into fundamental scientific issues such as solid-solid interface contact, (electro)chemical reactions, conductive networks, and battery performance failure. Composite cathode films, on the other hand, focus on the development and large-scale production of solid-state pouch batteries. Adding a certain amount of binder to composite cathode powder to prepare a composite cathode film with both rigidity and flexibility, low impedance, and high carrier transport capability is a prerequisite for the application of solid-state lithium batteries. Depending on the preparation method, the preparation of composite cathode films typically includes solid-phase and liquid-phase methods. The solid-phase method involves mixing, dispersing, and bonding the cathode active material, sulfide electrolyte, conductive agent, and binder in a certain mass ratio using equipment such as a planetary ball mill, mortar, or twin-screw extruder, followed by rolling to obtain the composite cathode film material. The liquid-phase method involves adding a certain mass of binder and organic solvent to the composite cathode powder, and then obtaining the composite cathode film electrode through processes such as mechanical stirring, slurry preparation, liquid-phase coating, solvent evaporation, high-temperature drying, and rolling to obtain the composite cathode film electrode.

[0003] Solid-state methods for preparing composite cathode films typically avoid the use of organic solvents and the decomposition of sulfide electrolytes, helping to reduce manufacturing costs and energy consumption. However, current solid-state preparation technology is still immature, resulting in composite cathode films with problems such as uneven dispersion of components, damage to the morphology and structure of the positive electrode active material particles, the need for multiple grinding or multi-stage rolling processes during film formation, and poor battery rate performance. For example, patent CN120376725 A describes a method that uses Li as the positive electrode active material... 1.75 Ti2(Mo 0.25 P 0.75 S 3.8 Se 0.2After mixing with the binder lithium thiooctanoate, a 150 μm thick composite cathode film was prepared by high-energy ball milling and subsequent pressing. However, the performance of the composite cathode film prepared by this high-energy mechanical ball milling is easily affected by the ball milling speed and time. In addition, continuous high-energy ball milling is prone to mechanochemical reactions, which destroy the structure of the cathode active material and the binder, affecting the electrochemical performance of the composite cathode film. Patent CN120497284 A provides a dry method for preparing a cathode film. First, the cathode active material, solid electrolyte, and conductive agent are mixed uniformly at room temperature to obtain a premix. Second, the premix is ​​mixed with the binder at low temperature to obtain a mixture. Then, the mixture is subjected to gradient fibrillation treatment under different processing temperatures, stirring speeds, and stirring times to obtain a fibrillated material. Furthermore, the fibrillated material is cooled and crushed and granulated using a pulse cooling strategy to obtain cathode powder. Finally, a highly fibrillated cathode film is obtained by multi-roll continuous rolling. Finally, the positive electrode film is composited with carbon-coated aluminum foil for current collector to obtain a dry-process positive electrode film. However, the binder in the composite positive electrode film prepared by this patent is highly fibrillated, resulting in low mechanical strength of the positive electrode film and limitations such as cumbersome preparation steps and complex processes. Patent CN120613374 A also provides a method for dry preparation of composite positive electrode films. In an argon atmosphere, a certain mass ratio of coated modified positive electrode active particles, sulfide electrolyte, conductive agent, and binder polytetrafluoroethylene are mixed evenly in a double planetary mixer. Then, the evenly mixed powder is placed in a mixer, heated, and pressurized to form a clump. Then, it is hot-rolled at high temperature to form a self-supporting positive electrode sheet, and finally hot-rolled composited with positive electrode current collector aluminum foil to obtain a positive electrode film. However, the dry preparation of composite positive electrode films proposed in this patent also has problems such as damaging the surface structure of positive electrode active particles, aggravating interfacial side reactions, and low mechanical strength of the positive electrode film.

[0004] Compared to dry film fabrication, liquid-phase preparation of composite cathode films facilitates uniform dispersion and good contact among the cathode active material particles, solid electrolyte, conductive agent, and binder, avoiding damage to the morphology and structure of the active material particles and achieving effective adhesion of the binder to the various components of the composite cathode. Furthermore, the liquid-phase composite cathode film preparation process can be matched with mature liquid lithium-ion battery membrane electrode production lines, reducing the manufacturing cost of solid-state batteries and enabling large-scale preparation of solid-state membrane electrodes. However, the liquid-phase preparation of composite cathode films requires comprehensive consideration of parameters such as binder, organic solvent, solid-liquid ratio, slurry preparation time, and drying temperature. For example, patent CN119314997 A first prepared a halide solid-state battery composite cathode slurry using ethanol solvent, then added polytetrafluoroethylene binder, and obtained a high-nickel ternary composite cathode film material through processes such as heating and thickening, slurry coating, roll forming, and high-temperature drying. The composite cathode film prepared by this patent achieves uniform dispersion and close contact of the components in the composite cathode. However, the highly polar ethanol solvent causes significant decomposition of the solid electrolyte, reduces the ionic conductivity of the solid electrolyte, generates high-impedance interfacial byproducts, and hinders the transport of lithium ions at the interface between the cathode active material and the solid electrolyte. In addition, high-temperature drying treatment also exacerbates the interfacial side reactions between the cathode active material and the solid electrolyte. Patent CN 120637642 A proposes a solution casting method for preparing composite cathode films. First, the cathode active material, conductive agent, first binder, and first solvent are mixed to obtain a cathode slurry, which is then coated on the surface of the cathode current collector. After drying, a cathode film with three-dimensional pores is obtained. Then, a halide electrolyte, a second binder, and a low-polarity second solvent are mixed to obtain a halide electrolyte solution, which is then cast onto the prepared cathode film, allowing the halide electrolyte solution to penetrate into the three-dimensional pores. Finally, after drying, a composite cathode sheet is obtained. This method significantly reduces the adverse effects of polar solvents on solid electrolytes and helps enhance the solid-solid interface contact between the solid electrolyte and the positive electrode active material. However, the solid electrolyte solution casting method proposed in this patent has specific requirements for the particle size of the active material, the particle size of the solid electrolyte, and the pore distribution and size of the positive electrode film. In addition, the solid electrolyte solution casting method is difficult to completely penetrate into the pores of the positive electrode film, resulting in uneven dispersion and non-dense contact of the active material, conductive agent, and solid electrolyte. Furthermore, the use of the first and second binders also reduces the capacity utilization of the composite positive electrode film. Therefore, based on the shortcomings of current composite positive electrode film material preparation technology, developing a novel liquid-phase method for preparing composite positive electrode films that is simple, low-cost, has minimal impact on lithium-rich manganese-based positive electrodes and sulfide electrolytes, exhibits excellent film-forming performance, and is applicable to mature liquid lithium-ion battery production lines has significant practical implications for the development of high-energy-density, high-safety lithium-rich manganese-based sulfide solid lithium batteries. Summary of the Invention

[0005] The main objective of this invention is to address the solvent sensitivity challenge encountered in the liquid-phase preparation of composite cathode films for sulfide solid-state lithium batteries, as well as the shortcomings of existing technologies in effectively guiding the preparation of lithium-rich manganese-based composite cathode films for high-energy-density sulfide solid-state lithium batteries. By developing a strategy that synergistically applies vapor-phase modification and low-polarity solvent liquid-phase coating, the difficulties encountered in preparing lithium-rich manganese-based composite cathode films for high-energy-density sulfide solid-state lithium batteries are effectively resolved. This invention provides a simple, low-cost, and easily scalable high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries, its preparation method, and its applications.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries, the slurry comprising a lithium-rich manganese-based composite cathode material and a binder solution, wherein the lithium-rich manganese-based composite cathode material comprises a lithium-rich manganese-based cathode active material, a gas-phase modified sulfide electrolyte, and a carbon-based conductive agent.

[0007] The lithium-rich manganese-based composite cathode material comprises a lithium-rich manganese-based cathode active material, a gas-phase modified sulfide electrolyte, and a carbon-based conductive agent, wherein the mass ratio of the lithium-rich manganese-based cathode active material, the gas-phase modified sulfide electrolyte, and the carbon-based conductive agent is 40-90: 60-10: 1-10.

[0008] The gas-phase modified sulfide electrolyte is prepared by placing the sulfide electrolyte in a sealed container and continuously introducing a weakly reactive gas at a flow rate of 1-500 ml / min for 0.5-6 h, so that the sulfide electrolyte and the gas can fully contact and react at room temperature; wherein the gas is one or more of carbon monoxide, carbon dioxide, and oxygen.

[0009] The lithium-rich manganese-based positive electrode active material is a lithium-rich manganese-based layered oxide. x Li2MnO3·(1 -x LiTMO2, where 0.3≤ x ≤0.7, TM consists of Ni, Co, and Mn elements, with a molar ratio of Ni, Co, and Mn of 3-8: 1-4: 1-3; the sulfide electrolyte is Li6PS5Cl, Li3PS4, Li6PS5Br, Li 10 GeP2S 12 One or more of the following; the carbon-based conductive agent is one or more of graphene, vapor-grown carbon fiber (VGCF), carbon nanotubes, and conductive carbon black (SP).

[0010] The mass ratio between the lithium-rich manganese-based composite cathode material and the binder solution is 4-6:6-4.

[0011] The adhesive solution is obtained by dissolving the adhesive in a low-polarity solvent; wherein the adhesive is one or more of styrene-butadiene rubber (SBR), hydrogenated nitrile butadiene rubber (HNBR), modified polyolefin (such as polyisobutylene PIB), or polyvinylidene fluoride (PVDF).

[0012] The low-polarity solvent is one or more of toluene, xylene, tetrahydrofuran, fluorinated alkanes, isoparaffins, and ester solvents, and the dielectric constant ε of the low-polarity solvent satisfies 1.5≤ε≤10.

[0013] The application of the aforementioned high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries, and the application of the slurry in the preparation of high-energy-density lithium-rich manganese-based composite cathode films for solid-state batteries.

[0014] A method for preparing a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries involves coating the obtained lithium-rich manganese-based composite cathode material slurry onto the surface of a conductive current collector, followed by heating and drying to obtain the high-energy-density lithium-rich manganese-based composite cathode film.

[0015] Specifically 1) Gas-phase modification: The sulfide electrolyte is placed in a 5-50 ml sealed container, and a weakly reactive gas is continuously introduced at a flow rate of 1-500 ml / min for 0.5-6 h. The surface of the sulfide electrolyte is passivated through the gas-solid interface reaction. 2) Positive electrode material: The above-mentioned gas-phase modified sulfide electrolyte, lithium-rich manganese-based positive electrode active material and carbon-based conductive agent are mixed in a mass ratio of 40-90: 60-10: 1-10. After mixing, the mixture is ground in the presence of an inert gas and set aside for use. 3) Liquid phase method for film formation: The binder and low polarity solution are mixed at a mass ratio of 0.1-3:10-7 and mechanically stirred at 30-90℃ for 0.5-4 h to form a binder solution (a glue solution containing the binder); then, the components are stirred and mixed according to the proportion of each component in the lithium-rich manganese-based composite cathode material slurry, and the mixed lithium-rich manganese-based composite cathode material slurry is coated on the surface of the conductive current collector and dried at 50-100℃ for 1-12 h to form a high-energy-density lithium-rich manganese-based composite cathode film.

[0016] Furthermore: (1) Take an appropriate amount of sulfide electrolyte and place it in a special glass container. The glass container is equipped with an inlet pipe and an outlet pipe and has good sealing performance. This design can ensure that when the gas enters the glass container, it can react with the sulfide electrolyte at a specific flow rate and avoid interference from environmental factors.

[0017] (2) Weigh the gas-phase modified sulfide electrolyte, high-energy lithium-rich manganese-based positive electrode active material and carbon-based conductive agent according to the set ratio and place them in a mortar. Manually grind them for a certain period of time in a glove box filled with argon gas and isolated from water and oxygen to achieve uniform mixing of each component.

[0018] Take an appropriate amount of polymer binder and add it to a specific low-polarity organic solvent. Under heating conditions, mechanically stir for a certain time to obtain a binder solution of a certain concentration. The low-polarity solution of the specific binder system can reduce its erosion of the sulfide electrolyte, while ensuring that the lithium-rich manganese-based composite cathode film has good film-forming characteristics.

[0019] (3) In the preparation stage of high-energy-density lithium-rich manganese-based composite cathode slurry, firstly, the binder-containing adhesive solution is added to the high-energy-density lithium-rich manganese-based composite cathode powder according to a specific mass ratio, and the binder molecules are allowed to penetrate between the active material, electrolyte, and conductive agent under low stirring speed. Then, the mechanical stirring speed is increased and the required low-polarity solvent is added according to the set solid-liquid ratio to complete the rapid slurry preparation with uniform mixing of each component and effective adhesion of the binder. Finally, the high-energy-density lithium-rich manganese-based composite cathode slurry is coated on the surface of the conductive current collector and dried under low-temperature vacuum heating conditions to achieve rapid evaporation of the solvent and obtain the high-energy-density lithium-rich manganese-based composite cathode film.

[0020] Application of a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries, wherein the high-energy-density lithium-rich manganese-based composite cathode film is used in sulfide electrolyte solid-state batteries.

[0021] A sulfide electrolyte all-solid-state battery, wherein the positive electrode of the battery is formed using the aforementioned composite positive electrode thin film material.

[0022] The electrolyte layer of the sulfide solid-state lithium battery is Li6PS5Cl, Li3PS4, Li6PS5Br, Li 10 GeP2S 12 One or more of the following. The negative electrode of the sulfide solid-state lithium battery is one of lithium metal negative electrode, lithium-indium negative electrode, carbon negative electrode, silicon negative electrode, and silicon-carbon negative electrode.

[0023] The fabrication of the sulfide solid-state lithium battery involves first placing 80 mg of sulfide solid electrolyte powder material into a solid-state battery mold with a diameter of 10 mm and applying a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, a high-energy-density lithium-rich manganese-based composite positive electrode film is cut into a 10 mm diameter piece and added from one side of the sulfide solid electrolyte layer, with a pressure of 800 MPa applied. Next, a certain mass of negative electrode material is placed on the other side of the sulfide solid electrolyte layer and a pressure of 200 MPa is applied. Finally, the fabrication of the sulfide electrolyte solid-state battery is completed by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0024] The sulfide solid-state lithium battery operates at 50 °C and 2.0-4.8 V (vs. Li). + / Li), 0.05 C (1 C=250 mA g -1 The device was activated once at 0.1 C, then activated twice at 0.1 C, and finally its charge-discharge performance was tested at 0.5 C.

[0025] In this invention, the surface of the sulfide solid electrolyte within the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is modified through gas-phase modification, which enhances the interfacial stability between the cathode active material and the solid electrolyte. Simultaneously, the use of low-polarity solvents and polymeric binders in the liquid-phase preparation of the composite cathode film, along with strategies such as rapid slurry preparation and low-temperature vacuum drying, significantly reduces the adverse effects of solvent polarity and drying temperature on the sulfide electrolyte and the interface between the cathode active material and the solid-state lithium battery.

[0026] Furthermore, a strategy of synergistically combining gas-phase modification and passivation of the sulfide electrolyte interface with rapid slurry preparation, coating, and film formation using low-polarity solvents was employed to prepare a high-energy-density lithium-rich manganese-based composite cathode film. The specific implementation process is as follows: An appropriate amount of sulfide electrolyte was placed in a specially designed glass bottle. A specific gas was introduced into the bottle at a certain flow rate and maintained for a certain period of time to achieve a uniform gas-solid interface reaction between the introduced gas and the sulfide electrolyte particles. The gas-phase modified sulfide electrolyte, the high-energy-density lithium-rich manganese-based cathode active material, and the carbon-based conductive agent were dry-premixed in a predetermined ratio to ensure uniform initial dispersion of each component. A low-polarity organic solvent for the binder was added to the mixed powder, the solid-liquid ratio was controlled, and rapid mechanical stirring was performed to obtain a high-energy-density lithium-rich manganese-based composite cathode slurry. The high-energy-density lithium-rich manganese-based composite cathode slurry was coated onto the surface of a conductive current collector, and the solvent was instantly removed using low-temperature vacuum rapid drying technology to form a dense, defect-free composite cathode film.

[0027] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: The strategy proposed in this invention, which combines gas-phase modification of sulfide electrolyte with liquid-phase coating of low-polarity solvent, solves the solvent sensitivity problem in the preparation of composite cathodes for sulfide all-solid-state batteries. The method of this invention achieves uniform dispersion and good contact of each component in the composite cathode while improving the interfacial stability between different components. This scheme has significant application potential and is of great significance for promoting the development of high-energy-density sulfide all-solid-state batteries.

[0028] (1) This invention utilizes the gas-solid interface reaction between a specific gas and sulfide electrolyte powder to achieve surface modification of the sulfide electrolyte, reducing the decomposition reaction of the sulfide electrolyte by low-polarity solvents. Simultaneously, the gas-phase modification of the sulfide electrolyte enhances the interfacial stability between the positive electrode active material and the sulfide electrolyte within the lithium-rich manganese-based composite positive electrode film, suppressing solid-solid interface reactions. Furthermore, the gas-phase modification, through the diffusion of gas molecules, can penetrate into the gaps and micropores of the powder particles, achieving a three-dimensional uniform coverage. Moreover, the gas-phase modification only acts on the material surface, eliminating the need to introduce liquid solvents, thus preventing solvent molecules from penetrating into the bulk phase of the sulfide electrolyte. Gas molecules do not enter the internal crystal lattice of the electrolyte, completely preserving its original ion conduction channels and bulk ion conductivity.

[0029] (2) Based on the gas-phase modification of the sulfide electrolyte surface, this invention further selects a binder solution containing low-polarity (or even ultra-low-polarity) solvents (such as long-chain alkanes, benzene derivatives, fluorinated solvents, etc.) for the rapid slurry preparation, coating, and subsequent low-temperature vacuum drying of the high-energy-density lithium-rich manganese-based composite cathode film. First, the low-polarity solution containing the binder can significantly reduce the decomposition reaction of the sulfide electrolyte. In addition, the rapid slurry preparation and coating process of the lithium-rich manganese-based composite cathode film further reduces the adverse effects of polar solvents. Furthermore, the low-temperature vacuum drying process can achieve rapid evaporation of polar solvents and avoid solid-solid interface side reactions between the lithium-rich manganese-based cathode active material and the sulfide electrolyte caused by high-temperature drying. Finally, the use of polymer binders helps to achieve close contact and effective adhesion between the lithium-rich manganese-based cathode active material, the electrolyte, and the conductive agent.

[0030] (3) The technical solution proposed in this invention has the advantages of simple process, low cost and can be matched with mature liquid lithium battery production line, which helps to reduce the manufacturing cost of high energy density lithium manganese-based composite cathode film and realize large-scale production. Attached Figure Description

[0031] Figure 1 In Example 1, (a) is a SEM image of the high-energy-density composite cathode film, (b) is a SEM image of the high-energy-density composite cathode powder, and (c) is a magnified SEM image and EDS image of the high-energy-density composite cathode film.

[0032] Figure 2 The first charge-discharge curve of the sulfide solid-state battery assembled with the high-energy-density sulfide composite cathode film material prepared in Example 1.

[0033] Figure 3 Cycle performance test of sulfide solid-state battery assembled with high specific energy sulfide composite cathode film material prepared in Example 1.

[0034] Figure 4The first charge-discharge curve of the sulfide solid-state battery assembled from the high-energy-density sulfide composite cathode film material prepared in Comparative Example 1.

[0035] Figure 5 Cycle performance testing of sulfide solid-state batteries assembled from the high-energy-density sulfide composite cathode film material prepared in Comparative Example 1. Detailed Implementation

[0036] The following examples further illustrate specific embodiments of the present invention. It should be noted that the specific embodiments described herein are merely for illustration and explanation and are not intended to limit the scope of the present invention.

[0037] This invention involves gas surface treatment of the sulfide electrolyte in the composite cathode material, utilizing gas-solid interfacial reactions to perform in-situ surface modification of the sulfide electrolyte, reducing solid-solid and liquid-solid interfacial side reactions between the sulfide electrolyte, the cathode active material, and the organic solvent. Secondly, a low-polarity solvent (such as long-chain alkanes, benzene derivatives, fluorinated solvents, etc.) is selected to prepare the composite cathode material slurry, followed by low-polarity solvent liquid-phase coating of the membrane electrode. This invention achieves uniform and close contact between the components within the composite cathode by developing a strategy of synergistic application of gas-phase modification and low-polarity solvent liquid-phase coating, constructing a continuous ion / electron transport network, reducing the "dead zone" of the cathode active material, and increasing the mass ratio of the cathode active material. Furthermore, the liquid-phase slurry preparation and coating strategy based on low-polarity organic solvents significantly reduces solvent erosion of the sulfide electrolyte, maintains the intrinsic ionic conductivity of the sulfide electrolyte, and contributes to improving the electrochemical performance of solid-state lithium batteries. Finally, the liquid-phase method for preparing composite cathode materials is also applicable to existing mature liquid lithium-ion battery membrane electrode fabrication lines, facilitating the mass production of solid-state battery membrane electrodes. This invention features a simple preparation process, low manufacturing cost, and compatibility with existing mature liquid lithium-ion battery production lines. While achieving uniform dispersion and good contact among the components within the composite cathode, it also improves the interfacial stability between different components. This approach has significant application potential and is of great importance in promoting the development of high-energy-density sulfide all-solid-state batteries.

[0038] All materials described in the following embodiments are commercially available; wherein, the cathode material is a lithium-rich manganese-based layered oxide. x Li2MnO3·(1 -x LiTMO2, 0.3≤ x ≤0.7, TM is composed of Ni, Co and Mn elements, and the molar ratio of Ni, Co and Mn elements in TM is 3-8: 1-4: 1-3; The sulfide electrolyte can be selected from Li6PS5Cl, Li3PS4, Li6PS5Br, Li 10 GeP2S 12One or more of the following; The carbon-based conductive agent can be selected from one or more of graphene, vapor-grown carbon fiber (VGCF), carbon nanotubes, and conductive carbon black (SP); The gas can be selected from one or more of carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), ammonia, and phosphorus pentasulfide; The low-polarity solvent can be selected from one or more of tetrahydrofuran (THF), isoalkanes (one or more of C8-C10 isoalkanes), toluene (TOL), fluoroalkanes, isoalkanes, and ester solvents. The binder may be selected from one or more of styrene-butadiene rubber (SBR), hydrogenated nitrile butadiene rubber (HNBR), modified polyolefins (such as polyisobutylene PIB), or polyvinylidene fluoride (PVDF).

[0039] Example 1 This embodiment prepares a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries. The lithium-rich manganese-based composite cathode material slurry forms a dense film with controllable thickness, uniform distribution of each component, and effective bonding on the current collector. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0040] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The cathode material consists of a sulfide electrolyte Li6PS5Cl modified by O2 and CO2 vapor phase, and a carbon-based conductive agent VGCF. The mass ratio of the single-crystal lithium-rich manganese-based layered oxide positive electrode active material, the CO2 vapor phase modified sulfide electrolyte Li6PS5Cl, and the carbon-based conductive agent VGCF is 75:25:5. Polyvinylidene fluoride (PVDF) is used as the binder, and low-polarity tetrahydrofuran (THF) is used as the solvent. The solid-liquid mass ratio of the lithium-rich manganese-based composite positive electrode slurry is controlled at 4:6.

[0041] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 250 mg of the sulfide electrolyte Li6PS5Cl into a 20 ml glass container in a glove box completely isolated from water and oxygen. After sealing the glass container, transfer it to a dry room with a low dew point (< -50 ℃) and connect it to a CO2 cylinder. Control the CO2 to enter the glass container at a uniform rate through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. Perform a gas-solid interface reaction at a gas flow rate of 100 ml / min for 1 h to achieve surface modification of Li6PS5Cl. After the reaction, transfer the CO2-modified Li6PS5Cl to the glove box under vacuum for later use.

[0042] Step 2: Weigh 750 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.16 Co 0.08 Mn 0.56 O2), the above-mentioned gas-phase modified sulfide electrolyte Li6PS5Cl 250mg and carbon-based conductive agent VGCF 50mg were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode, thus obtaining the lithium-rich manganese-based composite cathode powder material with the following microstructure: Figure 1 As shown in b.

[0043] Step 3: Weigh an appropriate amount of PVDF adhesive in a glove box and dissolve it in anhydrous tetrahydrofuran solution. Stir mechanically at 50 °C for 3 h to ensure that PVDF is completely dissolved in the anhydrous tetrahydrofuran solution, and obtain a PVDF adhesive solution with a mass fraction of 10%.

[0044] Step 4: Weigh the lithium-rich manganese-based composite cathode material from Step 2) into a 10 ml glass bottle and add a 1.5 cm magnetic dowel. Add the PVDF binder solution from Step 3) at a mass ratio of 95:5 for the composite cathode material to PVDF powder. Add additional tetrahydrofuran solvent to the glass bottle at a solid-liquid mass ratio of 4:6 for the composite cathode material + PVDF powder to tetrahydrofuran solvent. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0045] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the tetrahydrofuran solvent in the film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries. The microstructure is as follows: Figure 1 As shown in a and c.

[0046] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0047] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li) + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 224.49 mAh g. -1 The initial coulombic efficiency was 80.52%, and the capacity retention of the solid-state battery after 40 cycles was 91.82%. The initial charge / discharge data is as follows: Figure 2 Cyclic stability performance such as Figure 3 .

[0048] Depend on Figure 1 (a) and Figure 1 (b) As can be seen from the comparison, the liquid phase coating method achieves close contact between the components in the composite cathode and reduces the gaps between the components. Figure 1 (c) Magnified view of the composite positive electrode film and Figure 1 (d) The EDS diagram proves that the liquid-phase coating method achieves uniform mixing and close contact of the components in the composite cathode, thus constructing a continuous ion / electron transport network.

[0049] Example 2 In this embodiment, a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is prepared. A dense film with controllable thickness, uniform distribution of each component, and effective bonding is formed on the current collector by a lithium-rich manganese-based composite cathode material slurry. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0050] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni0.13 Co 0.13 Mn 0.54 The cathode material consists of an O2-modified sulfide electrolyte (Li6PS5Br) and a carbon-based conductive agent (VGCF). The mass ratio of the single-crystal lithium-rich manganese-based layered oxide positive electrode active material, the O2-modified sulfide electrolyte (Li6PS5Br), and the carbon-based conductive agent (VGCF) is 75:25:5. Polyvinylidene fluoride (PVDF) is used as the binder, and low-polarity tetrahydrofuran (THF) is used as the solvent. The solid-liquid mass ratio of the lithium-rich manganese-based composite positive electrode slurry is controlled at 4:6.

[0051] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 250 mg of the sulfide electrolyte Li6PS5Br into a 20 ml glass container in a glove box completely isolated from water and oxygen. After sealing the glass container, transfer it to a dry room with a low dew point (< -50 ℃) and connect it to an O2 gas cylinder. Control the O2 to enter the glass container at a uniform rate through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. Perform a gas-solid interface reaction at a gas flow rate of 50 ml / min for 1 h to achieve surface modification of Li6PS5Br. After the reaction is complete, transfer the O2-modified Li6PS5Br to the glove box under vacuum for later use.

[0052] Step 2: Weigh 750 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2), the above-mentioned gas-phase modified sulfide electrolyte Li6PS5Br 250mg and carbon-based conductive agent VGCF 50mg were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode, thus obtaining the lithium-rich manganese-based composite cathode material.

[0053] Step 3: Weigh an appropriate amount of PVDF adhesive in a glove box and dissolve it in anhydrous tetrahydrofuran solution. Stir mechanically at 50 °C for 3 h to ensure that PVDF is completely dissolved in the anhydrous tetrahydrofuran solution, and obtain a PVDF adhesive solution with a mass fraction of 10%.

[0054] Step 4: Weigh a certain mass of the lithium-rich manganese-based composite cathode material from Step 2) and place it in a 10 ml glass bottle, adding a 1.5 cm magnetic spool. Add the PVDF tetrahydrofuran solution from Step 3) according to a mass ratio of composite cathode powder to PVDF powder of 95:5. Add additional tetrahydrofuran solvent to the glass bottle according to a solid-liquid mass ratio of (composite cathode material + PVDF powder): tetrahydrofuran solvent of 4:6. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0055] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the tetrahydrofuran solvent in the lithium-rich manganese-based composite cathode film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

[0056] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0057] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li) + / Li), 0.05 C (1 C=250 mA g -1 Activation was performed once at the specified rate, at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 219.10 mAh g. -1 The first-cycle coulombic efficiency was 62.78%, and the capacity retention rate of the solid-state battery was 72.61% after 40 cycles.

[0058] Example 3 In this embodiment, a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is prepared. A dense film with controllable thickness, uniform distribution of each component, and effective bonding is formed on the current collector by a lithium-rich manganese-based composite cathode material slurry. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0059] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The slurry consists of an O2-modified sulfide electrolyte (Li6PS5Br) and a carbon-based conductive agent (VGCF). The mass ratio of the single-crystal lithium-rich manganese-based layered oxide positive electrode active material, the O2-modified sulfide electrolyte (Li6PS5Br), and the carbon-based conductive agent (VGCF) is 40:60:5. Polyisobutylene (PIB) is used as the binder, and low-polarity toluene is used as the solvent. The solid-liquid mass ratio of the lithium-rich manganese-based composite positive electrode material slurry is controlled at 5:5.

[0060] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 600 mg of the sulfide electrolyte Li6PS5Br into a 20 ml glass container in a glove box completely isolated from water and oxygen. After sealing the glass container, transfer it to a dry room with a low dew point (< -50 ℃) and connect it to an O2 gas cylinder. Control the O2 to enter the glass container at a uniform rate through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. Perform a gas-solid interface reaction at a gas flow rate of 50 ml / min for 1 h to achieve surface modification of Li6PS5Br. After the reaction is complete, transfer the O2-modified Li6PS5Br to the glove box under vacuum for later use.

[0061] Step 2: Weigh 400 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.16 Co 0.08 Mn 0.56 O2), the above-mentioned gas-phase modified sulfide electrolyte Li6PS5Br 600mg and carbon-based conductive agent VGCF 50mg were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode, and obtain lithium-rich manganese-based composite cathode material.

[0062] Step 3: Weigh an appropriate amount of PIB binder in a glove box and dissolve it in anhydrous toluene solution. Stir mechanically at 70 °C for 3 h to ensure that the PIB is completely dissolved in the anhydrous toluene solution, and obtain a PIB binder solution with a mass fraction of 10%.

[0063] Step 4: Weigh a certain mass of the lithium-rich manganese-based composite cathode material from Step 2) and place it in a 10 ml glass bottle, adding a 1.5 cm magnetic shovel. Add the PIB toluene solution from Step 3) according to a 95:5 mass ratio of composite cathode powder to PIB powder. Further add toluene solvent to the glass bottle according to a 5:5 solid-liquid mass ratio of (composite cathode material + PIB powder): toluene solvent. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0064] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the toluene solvent in the lithium-rich manganese-based composite cathode film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

[0065] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0066] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li) + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 232.38 mAh g. -1The first-cycle coulombic efficiency was 77.72%, and the capacity retention rate of the solid-state battery was 77.15% after 40 cycles.

[0067] Example 4 In this embodiment, a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is prepared. A dense film with controllable thickness, uniform distribution of each component, and effective bonding is formed on the current collector by a lithium-rich manganese-based composite cathode material slurry. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0068] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 O2) and CO2 gas-phase modified sulfide electrolyte Li 10 GeP2S 12 It is composed of a carbon-based conductive agent SP. The single-crystal lithium-rich manganese-based substrate oxide positive electrode active material is a CO2-modified sulfide electrolyte Li. 10 GeP2S 12 The mass ratio of carbon-based conductive agent SP is 60:40:3. Polyvinylidene fluoride (PVDF) is used as the binder, and low-polarity tetrahydrofuran (THF) is used as the solvent. The solid-liquid mass ratio of the lithium-rich manganese-based composite cathode material slurry is controlled at 4:6.

[0069] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 400 mg of sulfide electrolyte Li in a glove box completely isolated from water and oxygen. 10 GeP2S 12 The solution was placed in a 20 ml glass container, sealed, and transferred to a dry room with a low dew point (< -50 °C). A CO2 cylinder was connected, and CO2 was controlled to enter the glass container at a uniform rate through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. The gas-solid interface reaction was carried out at a gas flow rate of 100 ml / min for 1 h to achieve the reaction of Li... 10 GeP2S 12 Surface modification. After the reaction, the CO2-modified Li 10 GeP2S 12 Vacuum transfer to the glove box for later use.

[0070] Step 2: Weigh 600 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.16 Co 0.08 Mn0.56 O2), the above-mentioned gas-phase modified sulfide electrolyte Li 10 GeP2S 12 400 mg of lithium-rich manganese-based composite cathode material and 30 mg of carbon-based conductive agent SP were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode material, thus obtaining the lithium-rich manganese-based composite cathode material.

[0071] Step 3: Weigh an appropriate amount of PVDF binder in a glove box and dissolve it in anhydrous tetrahydrofuran solution. Stir mechanically at 50 °C for 3 h to ensure that PVDF is completely dissolved in the anhydrous tetrahydrofuran solution, and obtain a PVDF binder solution with a mass fraction of 10%.

[0072] Step 4: Weigh a certain mass of the lithium-rich manganese-based composite cathode material from Step 2) and place it in a 10 ml glass bottle, adding a 1.5 cm magnetic spool. Add the PVDF tetrahydrofuran solution from Step 3) according to a mass ratio of composite cathode powder to PVDF powder of 95:5. Add additional tetrahydrofuran solvent to the glass bottle according to a solid-liquid mass ratio of (composite cathode material + PVDF powder): tetrahydrofuran solvent of 4:6. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0073] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the tetrahydrofuran solvent in the lithium-rich manganese-based composite cathode film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

[0074] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0075] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li)+ / Li), 0.05 C (1 C=250 mA g -1 Activation was performed once at the specified rate, at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 218.03 mAh g. -1 The first-cycle coulombic efficiency was 68.01%, and the capacity retention rate of the solid-state battery was 72.86% after 40 cycles.

[0076] Example 5 In this embodiment, a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is prepared. A dense film with controllable thickness, uniform distribution of each component, and effective bonding is formed on the current collector by a lithium-rich manganese-based composite cathode material slurry. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0077] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The slurry consists of O2, ammonia-modified sulfide electrolyte Li6PS5Br, and carbon-based conductive agent VGCF. The mass ratio of the single-crystal lithium-rich manganese-based layered oxide positive electrode active material, the ammonia-modified sulfide electrolyte Li6PS5Br, and the carbon-based conductive agent VGCF is 80:20:4. Polyisobutylene (PIB) is used as the binder, and low-polarity toluene is used as the solvent, controlling the solid-liquid mass ratio of the lithium-rich manganese-based composite positive electrode material slurry to be 5:5.

[0078] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 200 mg of the sulfide electrolyte Li6PS5Br into a 20 ml glass container in a glove box completely isolated from water and oxygen. After sealing the glass container, transfer it to a dry room with a low dew point (< -50 ℃) and connect it to an ammonia cylinder. Control the ammonia gas to enter the glass container at a uniform rate through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. Perform a gas-solid interface reaction at a gas flow rate of 100 ml / min for 1 h to achieve surface modification of Li6PS5Br. After the reaction is complete, transfer the ammonia-modified Li6PS5Br to the glove box under vacuum for later use.

[0079] Step 2: Weigh 800 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.16 Co 0.08Mn 0.56 O2), the above-mentioned gas-phase modified sulfide electrolyte Li6PS5Br 200mg and carbon-based conductive agent VGCF 40mg were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode, thus obtaining the lithium-rich manganese-based composite cathode material.

[0080] Step 3: Weigh an appropriate amount of PIB binder in a glove box and dissolve it in anhydrous toluene solution. Stir mechanically at 70 °C for 3 h to ensure that the PIB is completely dissolved in the anhydrous toluene solution, and obtain a PIB binder solution with a mass fraction of 10%.

[0081] Step 4: Weigh a certain mass of the lithium-rich manganese-based composite cathode material from Step 2) and place it in a 10 ml glass bottle, adding a 1.5 cm magnetic shovel. Add the PIB toluene solution from Step 3) according to a 95:5 mass ratio of composite cathode powder to PIB powder. Further add toluene solvent to the glass bottle according to a 5:5 solid-liquid mass ratio of (composite cathode material + PIB powder): toluene solvent. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0082] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the toluene solvent in the lithium-rich manganese-based composite cathode film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

[0083] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0084] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li) + / Li), 0.05 C (1 C=250 mA g-1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 228.21 mAh g. -1 The first-cycle coulombic efficiency was 81.37%, and the capacity retention rate of the solid-state battery was 82.39% after 40 cycles.

[0085] Example 6 In this embodiment, a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is prepared. A dense film with controllable thickness, uniform distribution of each component, and effective bonding is formed on the current collector by a lithium-rich manganese-based composite cathode material slurry. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0086] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 O2) and CO gas-phase modified sulfide electrolyte Li 10 GeP2S 12 It is composed of carbon-based conductive agent CNT. The single-crystal lithium-rich manganese-based substrate oxide positive electrode active material is a CO gas-phase modified sulfide electrolyte, Li. 10 GeP2S 12 The mass ratio of carbon-based conductive agent (CNT) is 50:50:5. Polyisobutylene (PIB) is used as the binder, and low-polarity tetrahydrofuran (THF) is used as the solvent. The solid-liquid mass ratio of the lithium-rich manganese-based composite cathode material slurry is controlled at 4:6.

[0087] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 500 mg of sulfide electrolyte Li in a glove box completely isolated from water and oxygen. 10 GeP2S 12 The solution was placed in a 20 ml glass container, sealed, and transferred to a dry room with a low dew point (< -50 °C). A CO gas cylinder was connected, and CO was controlled to enter the glass container at a uniform rate through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. The gas-solid interface reaction was carried out at a gas flow rate of 100 ml / min for 1 h to achieve the reaction of Li... 10 GeP2S 12 Surface modification. After the reaction, CO-modified Li 10 GeP2S 12 Vacuum transfer to the glove box for later use.

[0088] Step 2: Weigh 500 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.16 Co 0.08 Mn 0.56 O2), the above-mentioned gas-phase modified sulfide electrolyte Li 10 GeP2S 12 500 mg of carbon-based conductive agent CNT and 50 mg of carbon-based conductive agent CNT were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode and obtain the lithium-rich manganese-based composite cathode material.

[0089] Step 3: Weigh an appropriate amount of PIB binder in a glove box and dissolve it in anhydrous tetrahydrofuran solution. Stir mechanically at 70 °C for 3 h to ensure that PIB is completely dissolved in the anhydrous tetrahydrofuran solution, and obtain a PIB binder solution with a mass fraction of 10%.

[0090] Step 4: Weigh a certain mass of the lithium-rich manganese-based composite cathode material from Step 2) and place it in a 10 ml glass bottle, adding a 1.5 cm magnetic spool. Add the PIB tetrahydrofuran solution from Step 3) according to a 95:5 mass ratio of composite cathode powder to PIB powder. Further add tetrahydrofuran solvent to the glass bottle according to a 4:6 solid-liquid mass ratio of (composite cathode material + PIB powder): tetrahydrofuran solvent. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0091] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the tetrahydrofuran solvent in the lithium-rich manganese-based composite cathode film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

[0092] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0093] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li) + / Li), 0.05 C (1 C=250 mA g -1 Activation was performed once at the specified rate, at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 209.55 mAh g. -1 The first-cycle coulombic efficiency was 76.65%, and the capacity retention rate of the solid-state battery after 40 cycles was 74.12%.

[0094] Example 7 In this embodiment, a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries is prepared. A dense film with controllable thickness, uniform distribution of each component, and effective bonding is formed on the current collector by a lithium-rich manganese-based composite cathode material slurry. The lithium-rich manganese-based composite cathode material slurry is composed of lithium-rich manganese-based composite cathode material and a low-polarity solution containing a binder.

[0095] Lithium-rich manganese-based composite cathode materials consist of single-crystal lithium-rich manganese-based layered oxide cathode active materials (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The slurry consists of a sulfide electrolyte (Li6PS5Br) modified with O2 and CO2 vapor phase and a carbon-based conductive agent (CNT). The mass ratio of the single-crystal lithium-rich manganese-based layered oxide positive electrode active material, the CO2-modified sulfide electrolyte (Li6PS5Br), and the carbon-based conductive agent (CNT) is 85:15:5. Polyisobutylene (PIB) is used as the binder, and low-polarity toluene is used as the solvent, controlling the solid-liquid mass ratio of the lithium-rich manganese-based composite positive electrode material slurry to be 5:5.

[0096] The specific preparation steps of the high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries provided in this embodiment are as follows: Step 1: Weigh 150 mg of the sulfide electrolyte Li6PS5Br into a 20 ml glass container in a glove box completely isolated from water and oxygen. After sealing the glass container, transfer it to a dry room with a low dew point (< -50 ℃) and connect it to a CO2 gas cylinder. Control the CO2 gas to enter the glass container at a uniform speed through the inlet pipe and exit into anhydrous ethanol through the exhaust pipe. Perform a gas-solid interface reaction at a gas flow rate of 100 ml / min for 1 h to achieve surface modification of Li6PS5Br. After the reaction, transfer the CO2-modified Li6PS5Br to a glove box under vacuum for later use.

[0097] Step 2: Weigh 850 mg of single-crystal lithium-rich manganese-based layered oxide positive electrode active material (Li) in a glove box completely isolated from water and oxygen. 1.2 Ni 0.16 Co 0.08 Mn 0.56 O2), the above-mentioned gas-phase modified sulfide electrolyte Li6PS5Br 150mg and carbon-based conductive agent CNT 50mg were added to a mortar and manually ground for 30 min to achieve uniform mixing of the powder materials in the lithium-rich manganese-based composite cathode, and obtain lithium-rich manganese-based composite cathode material.

[0098] Step 3: Weigh an appropriate amount of PIB binder in a glove box and dissolve it in anhydrous toluene solution. Stir mechanically at 70 °C for 3 h to ensure that the PIB is completely dissolved in the anhydrous toluene solution, and obtain a PIB binder solution with a mass fraction of 10%.

[0099] Step 4: Weigh a certain mass of the lithium-rich manganese-based composite cathode material from Step 2) and place it in a 10 ml glass bottle, adding a 1.5 cm magnetic shovel. Add the PIB toluene solution from Step 3) according to a 95:5 mass ratio of composite cathode powder to PIB powder. Add additional toluene solvent to the glass bottle according to a 5:5 solid-liquid mass ratio of (composite cathode material + PIB powder): toluene solvent. Stir the solid-liquid mixture rapidly at 30 °C for 30 min to obtain a lithium-rich manganese-based composite cathode material slurry.

[0100] Step 5: Pour the lithium-rich manganese-based composite cathode material slurry prepared in step 4) onto the aluminum foil current collector and coat it with a doctor blade. After coating, pre-dry it at 80 °C for 30 min using an electric heating plate, and then place it in a vacuum oven at 80 °C for 4 h to ensure that the toluene solvent in the lithium-rich manganese-based composite cathode film is completely evaporated and obtain a high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

[0101] Step 6: Assemble the high-energy-density lithium-rich manganese-based composite positive electrode film, Li6PS5Cl powder material, and lithium-indium alloy negative electrode material from Step 5) into a sulfide solid-state battery within an argon-filled glove box. First, place 80 mg of Li6PS5Cl electrolyte powder material in a 10 mm diameter solid-state battery mold and apply a pressure of 200 MPa to press it into a sulfide electrolyte layer. Then, cut the prepared high-energy-density lithium-rich manganese-based composite positive electrode film into a 10 mm diameter piece and add it from one side of the sulfide solid-state electrolyte layer, applying a pressure of 800 MPa. Next, place a certain mass of negative electrode material on the other side of the sulfide solid-state electrolyte layer and apply a pressure of 200 MPa. Finally, complete the fabrication of the sulfide electrolyte solid-state battery by tightening the sealing ring and applying external pressure using a mechanical clamp.

[0102] Step 7: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li) + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under [variable] rate conditions. The first discharge capacity reached 205.59 mAh g. -1 The first-cycle coulombic efficiency was 79.67%, and the capacity retention rate of the solid-state battery was 80.28% after 40 cycles.

[0103] Comparative Example 1 This comparative example prepares a high-energy-density composite cathode film for solid-state batteries, with the composite cathode material forming a film on a current collector; the composite cathode material is a lithium-rich manganese-based layered oxide active material (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The active materials consist of O2, a sulfide electrolyte (Li6PS5Cl, which is not gas-treated), and a carbon-based conductive agent VGCF. The ratio of lithium-rich manganese-based layered oxide active material: sulfide electrolyte Li6PS5Cl: carbon-based conductive agent VGCF is 75:25:5. Polyvinylidene fluoride (PVDF) is used as the binder, and tetrahydrofuran (THF) is used as the solvent, with the solid-liquid ratio of the slurry controlled at 4:6.

[0104] The specific preparation steps of the high-energy-density composite cathode thin film provided in this comparative example are as follows: Step 1: Weigh 750 mg of lithium-rich manganese-based basal oxide active material, 250 mg of sulfide electrolyte and 50 mg of carbon-based conductive agent VGCF in a glove box completely isolated from water and oxygen, add them to a mortar and grind for 10 min to achieve preliminary mixing.

[0105] Step 2: Weigh an appropriate amount of PVDF binder in a glove box and add it to anhydrous tetrahydrofuran solution. Stir at 50°C for 3 hours to ensure that PVDF is completely dissolved in the anhydrous tetrahydrofuran solution, thus preparing a PVDF binder solution.

[0106] Step 3: Weigh the preliminarily mixed composite cathode material from Step 1) and add it to a 10 ml glass bottle, along with a magnetic stir bar approximately 1.5 cm long. Add the tetrahydrofuran solution of PVDF from Step 2) to the glass bottle at a composite cathode material:PVDF powder mass ratio of 95:5. Then, add additional tetrahydrofuran solvent to the glass bottle at a solid-liquid mass ratio of (composite cathode material + PVDF powder:tetrahydrofuran solvent) of 4:6. Place the glass bottle in a magnetic stirrer and stir at 30 °C for 30 min to obtain the composite cathode slurry.

[0107] Step 4: Place the aluminum foil (used as the current collector) on a glass plate. Pour the composite cathode slurry prepared in step 3) evenly onto the current collector, keeping it as close to the scraper as possible, and then pull the scraper to coat the film. After coating, turn on the electric heating plate and set the temperature to 80 ℃. Dry for 4 hours to ensure that the tetrahydrofuran solvent in the composite cathode film completely evaporates. Finally, turn off the electric heating plate, remove the composite cathode film, and use a perforator to take a sample of the prepared composite cathode film.

[0108] Step 5: Assemble the lithium-rich manganese-based sulfide composite positive electrode film obtained in step 4), the sulfide electrolyte powder material, and the lithium-indium alloy negative electrode material into a sulfide solid-state battery in an argon-filled glove box.

[0109] Step 6: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li). + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under certain rate conditions. The first discharge capacity was only 151.12 mAh g. -1 The initial coulombic efficiency was 52.48%, and after 40 cycles, the solid-state battery capacity was reduced to only 41.67 mAh g. -1 The first charge / discharge data is as follows: Figure 4 Cyclic stability performance such as Figure 5 .

[0110] Comparative Example 2 This comparative example prepares a high-energy-density composite cathode powder for solid-state batteries. The composite cathode material is a lithium-rich manganese-based layered oxide active material (Li).1.2 Ni 0.16 Co 0.08 Mn 0.56 O2), sulfide electrolyte (sulfide electrolyte not treated with gas) Li6PS5Cl, and carbon-based conductive agent VGCF. The ratio of lithium-rich manganese-based layered oxide active material: sulfide electrolyte Li6PS5Cl: carbon-based conductive agent VGCF is 75: 25: 5.

[0111] The specific preparation steps of the high-energy-density composite cathode powder provided in this comparative example are as follows: Step 1: Weigh 750 mg of lithium-rich manganese-based basal oxide active material, 250 mg of atmosphere-free sulfide electrolyte, and 50 mg of carbon-based conductive agent VGCF in a glove box completely isolated from water and oxygen. Add them to a mortar and grind for 30 minutes to achieve preliminary mixing.

[0112] Step 2: Assemble the lithium-rich manganese-based sulfide composite cathode powder, sulfide electrolyte powder material, and lithium-indium alloy anode material obtained in step 1) into a sulfide solid-state battery in an argon-filled glove box.

[0113] Step 3: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li). + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under certain rate conditions. The first discharge capacity was only 213.08 mAh g. -1 The initial coulombic efficiency was 72.56%, and after 40 cycles, the solid-state battery capacity was reduced to only 34.13 mAh g. -1 .

[0114] Comparative Example 3 This comparative example prepares a high-energy-density composite cathode powder for solid-state batteries. The composite cathode material is a lithium-rich manganese-based layered oxide active material (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The active material consists of O2, oxygen-treated sulfide electrolyte Li6PS5Br, and carbon-based conductive agent VGCF. The ratio of lithium-rich manganese-based layered oxide active material to oxygen-treated sulfide electrolyte Li6PS5Br to carbon-based conductive agent VGCF is 40:60:5.

[0115] The specific preparation steps of the lithium-rich manganese-based composite cathode powder provided in this comparative example are as follows: Step 1: In a glove box completely isolated from water and oxygen, weigh 400 mg of lithium-rich manganese-based basal oxide active material, 600 mg of oxygen-treated sulfide electrolyte, and 50 mg of carbon-based conductive agent VGCF, add them to a mortar and grind for 30 minutes to achieve preliminary mixing.

[0116] Step 2: Assemble the lithium-rich manganese-based sulfide composite cathode powder, sulfide electrolyte powder material, and lithium-indium alloy anode material obtained in step 1) into a sulfide solid-state battery in an argon-filled glove box.

[0117] Step 3: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li). + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under certain rate conditions. The first discharge capacity was only 232.89 mAh g. -1 The initial coulombic efficiency was 63.34%, and after 40 cycles, the solid-state battery capacity was reduced to only 50.81 mAh g. -1 .

[0118] Comparative Example 4 This comparative example prepares a high-energy-density composite cathode film for solid-state batteries. The composite cathode material is formed on a current collector, and the composite cathode material is a lithium-rich manganese-based layered oxide active material (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56 The active materials consist of O2, a sulfide electrolyte (Li6PS5Br, which is not gas-treated), and a carbon-based conductive agent VGCF. The ratio of lithium-rich manganese-based layered oxide active material: sulfide electrolyte Li6PS5Br: carbon-based conductive agent VGCF is 40:60:5. Polyvinylidene fluoride (PVDF) is used as the binder, and NMP is used as the solvent, controlling the solid-liquid ratio of the slurry to be 4:6.

[0119] The specific preparation steps of the high-energy-density composite cathode thin film provided in this comparative example are as follows: Step 1: In a glove box completely isolated from water and oxygen, weigh 400 mg of lithium-rich manganese-based basal oxide active material, 600 mg of untreated sulfide electrolyte, and 50 mg of carbon-based conductive agent VGCF, add them to a mortar and grind for 20 minutes to achieve preliminary mixing.

[0120] Step 2: Weigh an appropriate amount of PVDF binder into the NMP solution in the glove box, and stir at 50 °C for 4 h to ensure that PVDF is completely dissolved in the NMP solution, thus preparing the PVDF binder solution.

[0121] Step 3: Weigh the composite cathode material from Step 1) and add it to a 10 ml glass bottle, along with a magnetic stir bar approximately 1.5 cm long. Add the NMP solution of PVDF from Step 2) to the glass bottle at a composite cathode material:PVDF powder mass ratio of 95:5. Then, add additional NMP solvent to the glass bottle at a solid-liquid mass ratio of (composite cathode material + PVDF powder:NMP solvent) of 4:6. Place the glass bottle in a magnetic stirrer and stir for 30 min at 30 °C to obtain the composite cathode slurry.

[0122] Step 4: Place the aluminum foil (used as a current collector) on a glass plate, pour the composite positive electrode slurry prepared in step 3) onto the current collector, and apply the coating using a scraper. After coating, turn on the electric heating plate, set the temperature to 80 ℃, and dry for 4 hours to ensure complete evaporation of the ethanol solvent within the composite positive electrode film. Finally, turn off the electric heating plate, remove the composite positive electrode film, and use a perforator to sample the prepared composite positive electrode film.

[0123] Step 5: Assemble the lithium-rich manganese-based sulfide composite positive electrode film obtained in step 4), the sulfide electrolyte powder material, and the lithium-indium alloy negative electrode material into a sulfide solid-state battery in an argon-filled glove box.

[0124] Step 6: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li). + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under certain rate conditions. The first discharge capacity was only 221.95 mAh g. -1 The initial coulombic efficiency was 65.07%, and after 40 cycles, the solid-state battery capacity was reduced to only 7.32 mAh g. -1 .

[0125] Comparative Example 5 This comparative example prepares a high-energy-density composite cathode film for solid-state batteries, with the composite cathode material forming a film on a current collector; the composite cathode material is a lithium-rich manganese-based layered oxide active material (Li). 1.2 Ni 0.16 Co 0.08 Mn 0.56O2), sulfide electrolyte (untreated sulfide electrolyte) Li 10 GeP2S 12 And carbon-based conductive agent SP. Among them, lithium-rich manganese-based layered oxide active material: untreated sulfide electrolyte Li 10 GeP2S 12 The carbon-based conductive agent VGCF ratio is 60:40:3. The binder is polyvinylidene fluoride (PVDF), and the solvent is ethanol. The solid-liquid ratio of the slurry is controlled at 4:6.

[0126] The specific preparation steps of the high-energy-density composite cathode thin film provided in this comparative example are as follows: Step 1: In a glove box completely isolated from water and oxygen, weigh 600 mg of lithium-rich manganese-based basal oxide active material, 400 mg of untreated sulfide electrolyte, and 30 mg of carbon-based conductive agent SP, add them to a mortar and grind for 20 minutes to achieve preliminary mixing.

[0127] Step 2: Weigh an appropriate amount of PVDF binder in a glove box and add it to the ethanol solution. Stir at 50 °C for 4 h to ensure that the PVDF is completely dissolved in the ethanol solution, thus preparing the PVDF binder solution.

[0128] Step 3: Weigh the composite cathode material from Step 1) and add it to a 10 ml glass bottle, along with a magnetic stir bar approximately 1.5 cm long. Add the PVDF ethanol solution from Step 2) to the glass bottle at a composite cathode material:PVDF powder mass ratio of 95:5. Then, add additional ethanol solvent to the glass bottle at a solid-liquid mass ratio of (composite cathode material + PVDF powder:ethanol solvent) of 4:6. Place the glass bottle in a magnetic stirrer and stir at 30 °C for 30 min to obtain the composite cathode slurry.

[0129] Step 4: Place the aluminum foil (used as a current collector) on a glass plate, pour the composite positive electrode slurry prepared in step 3) onto the current collector, and apply the coating using a scraper. After coating, turn on the electric heating plate, set the temperature to 80 ℃, and dry for 4 hours to ensure complete evaporation of the ethanol solvent within the composite positive electrode film. Finally, turn off the electric heating plate, remove the composite positive electrode film, and use a perforator to sample the prepared composite positive electrode film.

[0130] Step 5: Assemble the lithium-rich manganese-based sulfide composite positive electrode film obtained in step 4), the sulfide electrolyte powder material, and the lithium-indium alloy negative electrode material into a sulfide solid-state battery in an argon-filled glove box.

[0131] Step 6: Incubate the assembled sulfide solid-state battery at 50 °C and 2.0-4.8 V (vs. Li). + / Li), 0.05 C (1 C=250 mA g -1 Activate once at the specified rate, then activate twice at a rate of 0.1 C, and finally at 0.5 C (1 C = 250 mA g). -1 Charge-discharge performance was tested under certain rate conditions. The first discharge capacity was only 132.46 mAh g. -1 The initial coulombic efficiency was 50.12%, and after 40 cycles, the solid-state battery capacity was reduced to only 35.26 mAh g. -1 .

[0132] Table 1. Overview of Example Data

[0133] Table 2. Overview of Comparative Data

[0134] In summary, this invention uses inert gases such as carbon monoxide, carbon dioxide, and oxygen for gas-phase modification of solid sulfide electrolytes. Different solid-liquid ratios, types of conductive agents, composite cathode ratios, and solvent types are used to explore the influence of these gases. The conclusion is that gas-phase modification effectively reduces the likelihood of nucleophilic or redox reactions between the sulfide solid electrolyte and subsequently added low-polarity solvents. In sulfide solid-state batteries, the gas-phase modified sulfide electrolyte solid-state batteries exhibit superior charge-discharge cycle stability compared to those without any gas treatment. Specifically, the lithium-rich manganese-based sulfide composite cathode film treated with carbon dioxide (CO2) still retains 91.82% of its capacity after 40 cycles in a solid-state battery.

Claims

1. A high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries, characterized in that: The slurry includes a lithium-rich manganese-based composite cathode material and a binder solution. The lithium-rich manganese-based composite cathode material includes a lithium-rich manganese-based cathode active material, a gas-phase modified sulfide electrolyte, and a carbon-based conductive agent.

2. The high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries according to claim 1, characterized in that: The lithium-rich manganese-based composite cathode material comprises a lithium-rich manganese-based cathode active material, a gas-phase modified sulfide electrolyte, and a carbon-based conductive agent, wherein the mass ratio of the lithium-rich manganese-based cathode active material, the gas-phase modified sulfide electrolyte, and the carbon-based conductive agent is 40-90: 60-10: 1-10.

3. The high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries according to claim 2, characterized in that: The gas-phase modified sulfide electrolyte is prepared by placing the sulfide electrolyte in a sealed container and continuously introducing a weakly reactive gas at a flow rate of 1-500 ml / min for 0.5-6 h, so that the sulfide electrolyte and the gas can fully contact and react at room temperature; wherein the gas is one or more of carbon monoxide, carbon dioxide, and oxygen.

4. The high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries according to any one of claims 1-3, characterized in that: The lithium-rich manganese-based positive electrode active material is a lithium-rich manganese-based layered oxide. x Li2MnO3·(1 -x LiTMO2, where 0.3≤ x ≤0.7, TM consists of Ni, Co, and Mn elements, with a molar ratio of Ni, Co, and Mn of 3-8: 1-4: 1-3; the sulfide electrolyte is Li6PS5Cl, Li3PS4, Li6PS5Br, Li 10 GeP2S 12 One or more of the following; the carbon-based conductive agent is one or more of graphene, vapor-grown carbon fiber (VGCF), carbon nanotubes, and conductive carbon black (SP).

5. The high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries according to claim 1, characterized in that: The mass ratio between the lithium-rich manganese-based composite cathode material and the binder solution is 4-6:6-4.

6. The high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries according to claim 5, characterized in that: The adhesive solution is obtained by dissolving the adhesive in a low-polarity solvent; wherein the adhesive is one or more of styrene-butadiene rubber (SBR), hydrogenated nitrile butadiene rubber (HNBR), modified polyolefin (such as polyisobutylene PIB), or polyvinylidene fluoride (PVDF).

7. The high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries according to claim 6, characterized in that: The low-polarity solvent is one or more of toluene, xylene, tetrahydrofuran, fluorinated alkanes, isoparaffins, and ester solvents, and the dielectric constant ε of the low-polarity solvent satisfies 1.5≤ε≤10.

8. The application of the high-energy-density lithium-rich manganese-based cathode slurry for solid-state batteries as described in claim 1, characterized in that: The application of the slurry in the preparation of high-energy-density lithium-rich manganese-based composite cathode film for solid-state batteries.

9. A method for preparing a high-energy-density lithium-rich manganese-based composite positive electrode film for solid-state batteries, characterized in that: The lithium-rich manganese-based composite cathode material slurry obtained in claim 1 is coated on the surface of a conductive current collector, and then heated and dried to obtain a high-energy-density lithium-rich manganese-based composite cathode film.

10. The application of the high-energy-density lithium-rich manganese-based composite positive electrode film for solid-state batteries according to claim 9, characterized in that: Application of the high-energy-density lithium-rich manganese-based composite cathode film in sulfide electrolyte solid-state batteries.

Images