Cell composites and their preparation methods and all-solid-state batteries

Abstract

This invention discloses a cell composite, its preparation method, and an all-solid-state battery, belonging to the field of solid-state batteries. The preparation method includes: fabricating a positive and negative electrode sheet; preparing a non-Newtonian imprinted high-fluorine electrolyte substrate; preparing a solid electrolyte precursor suspension; spraying the solid electrolyte precursor suspension onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device, and then heating at 60°C for 5-10 minutes to fully fluorinate the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate surface with the solid electrolyte precursor suspension; imprinting the electrolyte layer coated on the non-Newtonian imprinted high-fluorine electrolyte substrate onto the positive electrode sheet using high-speed imprinting, then stacking the negative electrode sheet onto the surface of the imprinted electrolyte layer, and performing isostatic hot pressing to solidify the electrolyte layer and form the cell composite. Simultaneously, the cell composite prepared in the above steps improves the composite quality and efficiency between the electrolyte layer and the electrode sheet, and reduces interfacial impedance.

Description

Technical Field

[0001] This invention relates to the technical field of solid-state batteries, and in particular to a cell composite, a method for preparing the same, and an all-solid-state battery. Background Technology

[0002] Next-generation rechargeable lithium batteries with higher energy density and greater safety have emerged as an emerging technology, and commercially available rechargeable lithium-ion batteries (LIBs) are widely used in various fields due to their high energy density and long cycle life. However, current LIBs are struggling to meet future demands due to the limitations of specific capacity provided by intercalated anodes (graphite) (≤400 mAh / g) and thermal runaway caused by organic liquid electrolytes. To address these issues, all-solid-state batteries have become a hot research topic.

[0003] As a next-generation rechargeable battery, all-solid-state batteries currently face several complex manufacturing challenges, including unsuitable electrode microstructures, high production costs, and significant environmental impact. The unique properties of solid electrolytes necessitate novel electrode fabrication methods. While sulfide-based solid electrolytes exhibit excellent ionic conductivity, they also present challenges such as interfacial stability, particle mixing, and crystallinity effects, all of which significantly influence battery performance. Improper electrode formulations and high-impedance interfaces introduce substantial manufacturing uncertainties. To achieve high electrochemical performance, ionic and electronic pathways must be effectively established through the uniform distribution of active materials, conductive agents, binders, and solid electrolytes within the electrode.

[0004] There are two main existing methods for combining solid electrolytes and electrodes:

[0005] 1. Dry composite method: The prepared electrolyte membrane is hot-pressed together with the electrode, or the electrolyte powder and electrode powder are composited together simultaneously, rolled into a composite membrane, and then composited with the current collector.

[0006] 2. Wet coating: A wet slurry composed of electrolyte and solvent is coated onto the electrode sheet, or a double-layer coating is used to coat the electrode slurry and electrolyte slurry together onto the current collector, with the lower layer being the electrode layer and the upper layer being the electrolyte layer.

[0007] The above composite scheme has the following problems: the electrolyte and the electrode are mutually soluble, that is, the interface roughness is large and the electrode material and the electrolyte material permeate each other; there are many pores between the electrode and the electrolyte membrane, the interface contact is poor, resulting in high interface impedance. Summary of the Invention

[0008] This invention provides a composite of battery cells, a method for preparing the same, and an all-solid-state battery, to address the technical problems of improving the composite quality and efficiency between the electrolyte layer and the electrode sheet, as well as reducing interfacial impedance.

[0009] A method for preparing a battery cell composite according to the present invention includes the following steps:

[0010] S100: The positive and negative electrode sheets for preparing all-solid-state batteries;

[0011] S200: Preparation of non-Newtonian imprinted high-fluorine electrolyte matrix;

[0012] S300: Preparation of solid electrolyte precursor suspension;

[0013] S400: The solid electrolyte precursor suspension is sprayed onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device, and then heated at 60°C for 5~10 minutes to fully fluorinate the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate by the solid electrolyte precursor suspension, forming a fluorinated electrolyte layer.

[0014] S500: The fluorinated electrolyte layer formed on the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate is imprinted onto the positive electrode sheet at high speed. Then, the negative electrode sheet is stacked on the other side of the non-Newtonian imprinted high-fluorine electrolyte substrate and isostatically hot-pressed to solidify the electrolyte layer and generate a cell composite.

[0015] Further, S100 includes the following steps:

[0016] S101: Any one or more of the following high-nickel ternary cathode powder, lithium iron phosphate cathode powder, lithium manganese iron phosphate cathode powder, and lithium cobalt oxide cathode powder are mixed with conductive agent, binder, and solid electrolyte in a mass ratio of (65~93.5):(1~5):(0.5~2):(5~33.5) to form a mixed powder, which is then coated on aluminum foil or composite current collector and dried to obtain a cathode sheet;

[0017] S102: One or more of silicon-carbon, silicon suboxide, nano-silicon, and micron-silicon are mixed with graphite, binder, and solid electrolyte in a mass ratio of (0~70):(0~70):(2~5):(5~30), coated onto the surface of copper foil or composite current collector, and then dried to obtain a negative electrode sheet.

[0018] Further, step S200 includes the following steps:

[0019] S201: Fluorine-containing polymer, starch and lithium difluorooxalate borate are mixed and then added to a mixed solvent of methyl nylonate and dimethyl ether. The mixture is stirred thoroughly to generate the first electrolyte mixture. The mass ratio of fluorine-containing polymer, starch and lithium difluorooxalate borate is 5~20:30~60:10~20. The fluorine-containing polymer is polyvinylidene fluoride-hexafluoropropylene copolymer or polytetrafluoroethylene.

[0020] S202: Add 5-10% of the total mass of the first electrolyte mixture to the first electrolyte mixture and stir to generate the second electrolyte mixture.

[0021] S203: Transfer the second electrolyte mixture to a kneader and knead for 5~60 minutes to form the second electrolyte mixture into an electrolyte matrix. The temperature range during kneading is -20℃~60℃.

[0022] S204: The electrolyte matrix is ​​heated at 60°C for 2 hours to obtain a non-Newtonian imprinted high-fluorine electrolyte matrix.

[0023] Further, step S300 includes the following steps:

[0024] S301: Tetrabutyl titanate is mixed with citric acid and ethylene glycol to obtain a mixed solution. Then, La(NO3)3·6H2O and Sr(NO3)2 are dissolved in the mixed solution according to a preset molar ratio and stirred continuously to obtain a preliminary mixed solution.

[0025] S302: Heat the preliminary mixture in a water bath at 60~120℃ and stir until a gel is formed;

[0026] S303: Dry the gel at 200~300℃ for 2~4 hours to remove organic components and nitrates, and obtain the precursor powder;

[0027] S304: After pulverizing the precursor powder, sinter it at 700~1000℃ for 5~12 hours to obtain the raw material;

[0028] S305: Ball milling of raw materials to prepare lanthanum strontium titanate nanoparticles;

[0029] S306: One or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polymethyl methacrylate, and polyacrylonitrile, along with strontium lanthanum titanate nanoparticles, are dissolved in N,N-dimethylformamide and mechanically stirred at 65°C for 24 hours to obtain a uniformly dispersed solid electrolyte precursor suspension.

[0030] Further, step S300 includes the following steps:

[0031] S301: A primary mixture is prepared by mixing one or more of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate and polyethylene glycol methacrylate with trifluoroethyl methacrylate in a mass ratio of (1~5):(10~100).

[0032] S302: Add lithium bis(trifluoromethanesulfonyl)imide to the primary mixture, stir thoroughly to dissolve, and mix completely to obtain a secondary mixture. The mass of lithium bis(trifluoromethanesulfonyl)imide added is 13-20% of the primary mixture.

[0033] S303: Add tetrahydrothiophene sulfone to the secondary mixture and mix thoroughly to obtain a solid electrolyte precursor suspension, wherein the mass of tetrahydrothiophene sulfone added is 2~7% of the secondary mixture.

[0034] Furthermore, in step S400, the coating thickness formed by spraying the solid electrolyte precursor suspension onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device is 10~50μm.

[0035] Furthermore, in step S500, the isostatic hot pressing pressure is 400MPa~600MPa, the temperature is 60~80℃, and the holding time is 5~60min.

[0036] Furthermore, in step S500, after isostatic hot pressing, the battery cell composite is dried in a vacuum environment at 78~82℃ for 10~14h.

[0037] The present invention also discloses a battery cell composite, which is obtained by the battery cell composite preparation method described above, including a positive electrode, a negative electrode, and a composite electrolyte layer disposed between the positive electrode and the negative electrode. The composite electrolyte layer is a non-Newtonian imprinted high-fluorine electrolyte substrate with a fluorinated electrolyte layer coated on its surface.

[0038] The present invention also discloses an all-solid-state battery, comprising the above-described cell composite.

[0039] The present invention has the following beneficial effects:

[0040] In the preparation method of the battery cell composite of the present invention, the non-Newtonian imprinted high-fluorine electrolyte matrix has the advantage of high fluidity, which allows the surface-sprayed solid electrolyte precursor suspension to be better filled into the micropores and uneven areas on the electrode surface during subsequent imprinting, achieving a more perfect fit. Then, by spraying the solid electrolyte precursor suspension onto the surface of the non-Newtonian imprinted high-fluorine electrolyte matrix, the solid electrolyte precursor solution will undergo a slight chemical reaction with the non-Newtonian imprinted high-fluorine electrolyte matrix, thereby fluorinating the electrolyte and forming a stable fluorinated solid electrolyte interface film. When this film is used with the electrode, it has the effect of reducing interfacial impedance, suppressing side reactions, and improving the chemical and mechanical stability of the interface. Finally, by using a high-speed imprinting-superposition-isostatic hot pressing process, the positive electrode, electrolyte layer and negative electrode are solidified into a tight whole. In summary, surface fluorination pretreatment of the electrolyte reduces interfacial impedance, suppresses side reactions, and improves interfacial chemical and mechanical stability when the electrolyte is combined with the electrode. At the same time, the high-speed imprinting-stacking-isostatic hot pressing process solidifies the positive electrode, electrolyte layer, and negative electrode into a tight whole. Through the above process combination, interfacial compatibility is improved at the molecular level, and strong and rapid physical composite is achieved at the macroscopic level, thereby preparing a battery cell composite with low interfacial impedance, high interfacial bonding strength, and stable and consistent structure.

[0041] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0042] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0043] Figure 1 This is a flowchart illustrating the manufacturing process of the battery cell composite of the present invention;

[0044] Figure 2 This is an interface SEM image of a preferred embodiment 1 of the battery cell composite of the present invention;

[0045] Figure 3 These are linear graphs of the internal resistance pressure under different imprinting pressures for preferred embodiment 1 and comparative example 2 of the present invention;

[0046] Figure 4 This is a linear graph comparing the cycle performance of preferred embodiment 1 and comparative example 2 of the present invention. Detailed Implementation

[0047] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0048] Reference Figure 1 and Figure 2 The present invention discloses a method for preparing a battery cell composite, comprising the following steps:

[0049] S100: Used to manufacture the positive and negative electrode plates for all-solid-state batteries;

[0050] S200: Preparation of non-Newtonian imprinted high-fluorine electrolyte matrix;

[0051] S300: Prepare and configure a solid electrolyte precursor suspension;

[0052] S400: The solid electrolyte precursor suspension is sprayed onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device, and then heated at 60°C for 5~10 minutes to fully fluorinate the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate by the solid electrolyte precursor suspension, forming a fluorinated electrolyte layer.

[0053] S500: The fluorinated electrolyte layer formed on the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate is imprinted onto the positive electrode sheet at high speed. Then, the negative electrode sheet is stacked on the other side of the non-Newtonian imprinted high-fluorine electrolyte substrate and isostatically hot-pressed to solidify the electrolyte layer and generate a cell composite.

[0054] In this embodiment, for step S100, the prepared positive and negative electrode sheets are cut to the required dimensions.

[0055] For step S200, the non-Newtonian imprinting of the high-fluorine electrolyte matrix means that the viscosity of the matrix changes under different shear forces. Under high pressure, it may become thinner, easily flowing and filling the micropores on the electrode surface; after the pressure is removed, it returns to high viscosity / solid state, maintaining its shape. This ensures perfect close contact with the electrode during the imprinting process. At the same time, the introduction of the fluorinated polymer provides excellent electrochemical stability and high lithium-ion conductivity, and can form a stable fluorinated electrolyte layer with the subsequent solid electrolyte precursor suspension, specifically a solid electrolyte interphase (SEI) film.

[0056] In step S300, the solid electrolyte precursor suspension undergoes physical or chemical bonding with the substrate and electrode in subsequent processing to enhance interfacial strength. Specifically, it is sprayed onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate. The portion in contact with the non-Newtonian imprinted high-fluorine electrolyte substrate undergoes a fluorination reaction to form a stable solid electrolyte interfacial membrane (SEI membrane), while the sprayed surface remains unchanged. Specifically, during electrode imprinting, the portion that remains unchanged is imprinted with the positive electrode, and the portion that undergoes the fluorination reaction is imprinted with the negative electrode. This can protect the highly active negative electrode interface, form a stable solid electrolyte interfacial membrane (SEI membrane), suppress dendrites, and reduce interfacial impedance.

[0057] For step S400, high-speed spraying forms a uniform, ultra-thin coating, ensuring the uniformity and consistency of the treatment. Heating and fluorination allow the components in the suspension to chemically react or physically penetrate the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate, achieving full fluorination. This creates a transition layer on the substrate surface that is more compatible with the chemical properties of the suspension and subsequent electrode interfaces. This activation layer greatly improves the lithium-ion migration ability between the substrate and the subsequently coated electrolyte layer, thereby reducing interfacial impedance.

[0058] For step S500, as Figure 1 As shown, the high-speed imprinting process utilizes the non-Newtonian properties of the substrate to force and tightly embed the electrolyte layer into the porous structure of the positive electrode under instantaneous ultra-high pressure, forming a huge contact area and mechanical interlocking structure. After the negative electrode is stacked, isostatic pressing is performed. At this time, the electrolyte layer that maintains its original shape is imprinted with the positive electrode, while the part that has undergone the fluorination reaction is imprinted with the negative electrode. The isostatic pressing method provides uniform pressure from all directions, ensuring that the force is uniform and the contact is consistent among the layers of the entire cell composite (positive electrode-electrolyte-negative electrode), without local defects. Finally, the electrolyte is solidified by hot pressing, transforming it from a precursor state into a strong and dense solid electrolyte layer, while forming a strong chemical / physical bond with the positive and negative electrodes.

[0059] Specifically, the prepared non-Newtonian imprinted high-fluorine electrolyte substrate has the advantage of high fluidity, which allows the surface-sprayed solid electrolyte precursor suspension to better fill the micropores and uneven areas on the electrode surface during subsequent imprinting, achieving a more perfect fit. Then, by spraying the solid electrolyte precursor suspension onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate, the solid electrolyte precursor solution will undergo a slight chemical reaction with the non-Newtonian imprinted high-fluorine electrolyte substrate, thereby fluorinating the electrolyte and forming a stable fluorinated solid electrolyte interface film. When this film is used with the electrode, it can reduce interfacial impedance, suppress side reactions, and improve the chemical and mechanical stability of the interface. Finally, the positive electrode, electrolyte layer and negative electrode are solidified into a tight whole by using a high-speed imprinting-superposition-isostatic hot pressing process. In summary, surface fluorination pretreatment of the electrolyte reduces interfacial impedance, suppresses side reactions, and improves interfacial chemical and mechanical stability when the electrolyte is combined with the electrode. At the same time, the high-speed imprinting-stacking-isostatic hot pressing process solidifies the positive electrode, electrolyte layer, and negative electrode into a tight whole. Through the above process combination, interfacial compatibility is improved at the molecular level, and strong and rapid physical composite is achieved at the macroscopic level, thereby preparing a battery cell composite with low interfacial impedance, high interfacial bonding strength, and stable and consistent structure.

[0060] Further, S100 includes the following steps:

[0061] S101: Any one or more of the following: high-nickel ternary cathode powder, lithium iron phosphate cathode powder, lithium manganese iron phosphate cathode powder, and lithium cobalt oxide cathode powder, are mixed with a conductive agent, a binder, and a solid electrolyte in a ratio of (65~93.5):(1~5):(0.5~2):(5~33.5) to form a mixed powder, which is then coated on an aluminum foil or a composite current collector and dried to obtain a cathode sheet;

[0062] S102: One or more of silicon-carbon, silicon suboxide, nano-silicon, and micron-silicon are mixed with graphite, binder, and solid electrolyte in a mass ratio of (0~70):(0~70):(2~5):(5~30), coated onto the surface of copper foil or composite current collector, and then dried to obtain a negative electrode sheet.

[0063] In this embodiment, for step S100, high-nickel ternary cathode powder, lithium iron phosphate cathode powder, lithium manganese iron phosphate cathode powder, lithium cobalt oxide cathode powder, or combinations thereof are selected, covering cathode materials from high energy density to high safety. Among them, high-nickel ternary cathode powder provides extremely high energy density and is the first choice for addressing range anxiety; lithium iron phosphate cathode powder provides excellent safety and cycle life at a lower cost; lithium manganese iron phosphate cathode powder improves voltage and energy density compared to lithium iron phosphate, making it a new choice that balances performance and safety; and lithium cobalt oxide cathode powder has high compaction density. Furthermore, in practical applications, these materials can also be compounded, for example, high-nickel powder can be mixed with LFP to balance energy density and safety. Simultaneously, it is formulated into a mixed powder with conductive agent, binder, and solid electrolyte in a ratio of (65~93.5):(1~5):(0.5~2):(5~33.5). The high content of positive electrode powder with high active material directly improves the electrode's capacity per unit area and the battery's energy density. The solid electrolyte reduces interfacial impedance and optimizes stress distribution. The conductive agent and binder, while ensuring a good electronic conductivity network and sufficient bonding strength, minimize the proportion of inactive materials, further contributing to increased energy density. Simultaneously, the low binder content also benefits ion transport. In practice, it is coated onto aluminum foil or composite current collectors of any thickness using dry or wet processes, followed by 105°C forced-air drying to obtain the positive electrode sheet.

[0064] For step S200, customized design of the negative electrode is allowed according to application requirements. A smooth transition can be made from traditional pure graphite negative electrodes to high-capacity silicon-carbon composite negative electrodes (e.g., silicon:graphite mass ratio of 15:55), and even negative electrodes with higher silicon content. A higher binder content than the positive electrode is crucial for maintaining the structural integrity of the silicon negative electrode during charge and discharge, preventing electrode pulverization and ensuring cycle stability. In practice, the binder is coated onto the surface of copper foil or composite current collector of any thickness and dried at 95 degrees Celsius. The negative electrode sheet is then cut to the required size, leaving the tabs, for later use.

[0065] Further, step S200 includes the following steps:

[0066] S201: Fluorine-containing polymer, starch and lithium difluorooxalate borate are mixed and then added to a mixed solvent of methyl nylonate and dimethyl ether (DME). The mixture is stirred thoroughly to generate an electrolyte first mixture. The mass ratio of fluorine-containing polymer, starch and lithium difluorooxalate borate is (5~20):(30~60):(10~20). The fluorine-containing polymer is polyvinylidene fluoride-hexafluoropropylene copolymer or polytetrafluoroethylene.

[0067] S202: Add 5-10% of the total mass of the first electrolyte mixture to the first electrolyte mixture and stir to generate the second electrolyte mixture;

[0068] S203: Transfer the second electrolyte mixture to a kneader and knead for 5~60 minutes to form the second electrolyte mixture into an electrolyte matrix. Adjust the temperature to -20℃~60℃ during kneading.

[0069] S204: The electrolyte matrix is ​​heated at 60°C for 2 hours to obtain a non-Newtonian imprinted high-fluorine electrolyte matrix.

[0070] In this embodiment, for step S201, a first electrolyte mixture is prepared, in which starch has the highest content and serves as the main framework of the matrix. Starch gelatinization exhibits typical non-Newtonian fluid behavior, such as shear thinning, which is crucial for subsequent imprinting processes. Combining it with other components can adjust the flexibility and mechanical strength of the matrix. Polyvinylidene fluoride-hexafluoropropylene copolymer and polytetrafluoroethylene are fluorinated polymers with extremely wide electrochemical windows, capable of withstanding high voltages at the positive electrode and preventing electrolyte oxidation. Lithium difluorooxalate-borate serves as the core of the electrolyte, providing migratable lithium ions.

[0071] For step S202, fluoroethylene carbonate, a classic electrolyte additive, is introduced here as a fluorinated component.

[0072] For step S203, the second electrolyte mixture is transferred to a kneader and kneaded for 5-60 minutes at a temperature between -20°C and 60°C. Kneading is a high-shear mixing process that ensures uniform dispersion of starch, fluorinated polymers, lithium salts, and fluoroethylene carbonates at the molecular level, avoiding localized component segregation. The low-temperature kneading at -20°C may be used to prevent solvent evaporation or control specific reactions; 60°C promotes gelatinization and mixing efficiency. This wide process window is beneficial for industrial production control.

[0073] In step S204, the residual solvent is evaporated by heat treatment, which further solidifies the matrix structure and obtains stable mechanical properties.

[0074] Further, step S300 includes the following steps:

[0075] S301: Tetrabutyl titanate is mixed with a small amount of citric acid and ethylene glycol to obtain a mixed solution. Then, La(NO3)3·6H2O and Sr(NO3)2 are dissolved in the mixed solution according to a preset molar ratio and stirred continuously to obtain a preliminary mixed solution.

[0076] S302: Heat the preliminary mixture in a water bath at 60~120℃ and stir until a gel is formed;

[0077] S303: Dry the gel at 200~300℃ for 2~4 hours to remove organic components and nitrates, and obtain the precursor powder;

[0078] S304: After pulverizing the precursor powder, sinter it at 700~1000℃ for 5~12 hours to obtain the raw material;

[0079] S305: Ball milling of raw materials to prepare lanthanum strontium titanate nanoparticles;

[0080] S306: One or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polymethyl methacrylate, and polyacrylonitrile, along with strontium lanthanum titanate nanoparticles, are dissolved in N,N-dimethylformamide and mechanically stirred at 65°C for 24 hours to obtain a uniformly dispersed solid electrolyte precursor suspension.

[0081] In this embodiment, for step S301, starting with liquid raw materials such as nitrates and tetrabutyl titanate, a uniform mixture of lanthanum (La), strontium (Sr), and titanium (Ti) ions is achieved in the presence of citric acid and ethylene glycol. This avoids the problem of uneven mechanical mixing in traditional solid-phase methods and ensures a high degree of uniformity in the chemical composition of the final product. Specifically, the mass ratio of tetrabutyl titanate to citric acid and ethylene glycol is (60~80):(1~10):(10~40), with tetrabutyl titanate (titanium source) having the highest proportion, ensuring the presence of Ti ions in the system. 4+ A sufficient supply of the core metal element is provided for the target product. Citric acid acts as a chelating agent, and its ratio must match the total amount of metal ions. Further precise control is achieved by using a ratio of "metal ions: citric acid = 1:2". Its role is to react with Ti... 4+ La 3+ 、Sr 2+ The formation of stable coordination compounds prevents premature hydrolysis and precipitation of metal ions, ensuring uniform dispersion. Ethylene glycol, as a co-solvent and cross-linking agent, promotes the coordination reaction between citric acid and metal ions by adjusting the viscosity of the system, while enhancing the stability of the sol and providing a suitable fluid environment for the subsequent formation of a uniform gel.

[0082] The molar ratio of La(NO3)3·6H2O to Sr(NO3)2 is maintained at 1:(0.5-5). This ratio directly determines the target product, such as La in LSTO. 3+ With Sr 2+ The stoichiometric composition of the product is determined by adjusting the ratio of the two components. This allows for precise control of the product's crystal structure, such as lattice parameters and doping concentration, thereby ensuring that its physicochemical properties, such as ionic conductivity and thermal stability, meet design requirements. This is fundamental to achieving the product's functional characteristics.

[0083] At the same time, ensure that the molar ratio of metal ions to citric acid in the final preliminary mixture is 1:2, where "metal ions" refers to Ti. 4+ La 3+ 、Sr 2+ The total number of moles, the "1:2" ratio ensures that the amount of citric acid is sufficient to completely encapsulate all metal ions: the carboxyl group (-COOH) in the citric acid molecule can form a multidentate coordination bond with the metal ions, forming a stable soluble complex, which fundamentally avoids the aggregation or precipitation of metal ions in the solution due to excessively high local concentration, and ultimately achieves uniform mixing of the three metal ions at the molecular level. This is the core control method to overcome the defect of "uneven mechanical mixing" in the traditional solid-phase method.

[0084] In step S302, the solvent is evaporated by heating, which initiates a polymerization reaction to form a gel network, thereby fixing the metal ions within it.

[0085] For step S303, organic matter and nitrate ions are removed at a relatively low temperature (200~300℃). This step avoids the sudden generation of a large amount of gas at high temperatures, which could damage the powder structure and ensures the production of a loose, porous precursor, which is beneficial for subsequent sintering.

[0086] For step S304, heat treatment is performed at 700~1000℃ to crystallize the amorphous precursor into lanthanum strontium titanate (LSTO) with a perovskite crystal structure.

[0087] In step S305, the sintered powder typically agglomerates into large micron-sized particles. These are then broken down into nanoparticles by ball milling.

[0088] For step S306, the design of "multi-polymer combination formulation control + lithium lanthanum titanate nanoparticle composite" achieves synergistic optimization of the conductivity, interfacial compatibility, and mechanical stability of the solid electrolyte precursor suspension, and also possesses flexible formulation adaptability. Specifically, the binary formulation uses polyethylene oxide as the core ion-conducting substrate, combined in a 1:2 ratio of polyethylene oxide to polyvinylidene fluoride-hexafluoropropylene copolymer. While ensuring basic ion conductivity, the high-strength mechanical framework constructed with twice the amount of polyvinylidene fluoride-hexafluoropropylene copolymer effectively inhibits lithium dendrite penetration. The ternary formulation uses a 1:(0.5~1):(1~3) ratio of polyethylene oxide to polymethyl methacrylate to polyvinylidene fluoride-hexafluoropropylene copolymer. Polyethylene oxide maintains ion conduction efficiency, while polymethyl methacrylate inhibits polyethylene oxide crystallization and improves the interfacial contact between the electrolyte and electrode, reducing interfacial resistance. The ternary formulation adds polyacrylonitrile to the ternary system, using a ratio of polyethylene oxide:polyacrylonitrile:polymethyl methacrylate:polyvinylidene fluoride-hexafluoropropylene copolymer = 1:(0.5~1):(1~3):2. Polyacrylonitrile can improve the interfacial stability between the electrolyte and the lithium anode and reduce side reactions. It can also synergistically optimize the interfacial compatibility with polymethyl methacrylate and synergistically enhance the mechanical strength with polyvinylidene fluoride-hexafluoropropylene copolymer, maximizing the freedom of formulation control to adapt to highly demanding application scenarios. Meanwhile, the polymer composition is compounded with lithium lanthanum titanate nanoparticles at a weight ratio of 1:(0.01~0.75). This not only binds the lithium lanthanum titanate nanoparticles into a complete, dense, and flexible thin film structure, preventing particle agglomeration, but also forms an "inorganic-organic" synergistic conduction network by utilizing the efficient ion channels of the lithium lanthanum titanate inorganic fast ion conductor and the auxiliary ion transport pathway of the polymer matrix, further improving the total ionic conductivity of the electrolyte. Overall, this design, through the flexible combination and ratio adjustment of binary, ternary, and quaternary polymers, can control various electrolyte properties as needed, achieving a balance between structural integrity and superior performance, providing a solid foundation for the subsequent preparation of high-performance solid electrolytes.

[0089] Furthermore, in step S301, specifying a "molar ratio of metal ions to citric acid of 1:2" has significant and positive benefits in the sol-gel method. This ratio is not arbitrarily chosen but is based on the chemical coordination ability of citric acid, aiming to achieve optimal synthetic results. Citric acid is a polydentate ligand with three carboxyl groups (-COOH) and one hydroxyl group (-OH). In solution, these groups can react with the metal ions (Ti) in the step. 4+ La 3+ 、Sr 2+ Strong coordination occurs, forming a stable metal-citric acid complex. The significance of a 1:2 molar ratio: Ti4+ Ions have high charge density and strong coordination ability. A Ti 4+ Theoretically, citric acid ions can coordinate with multiple citric acid molecules. Maintaining a metal ion:citric acid molar ratio of 1:2 ensures the presence of sufficient or even excess citric acid in the solution. This guarantees the presence of all metal ions, especially Ti, which has high coordination requirements. 4+ All of them can be fully surrounded and complexed by citric acid molecules, preventing them from undergoing separate hydrolysis or precipitation in subsequent steps.

[0090] In yet another embodiment, step S300 includes the following steps:

[0091] S301: A primary mixture is prepared by mixing one or more of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate and polyethylene glycol methacrylate with trifluoroethyl methacrylate in a mass ratio of (1~5):(10~100).

[0092] S302: Add lithium bis(trifluoromethanesulfonyl)imide to the primary mixture, stir thoroughly to dissolve, and mix completely to obtain a secondary mixture. The mass of lithium bis(trifluoromethanesulfonyl)imide added is 13-20% of the primary mixture.

[0093] S303: Add tetrahydrothiophene sulfone to the secondary mixture and mix thoroughly to obtain a solid electrolyte precursor suspension, wherein the mass of tetrahydrothiophene sulfone added is 2~7% of the secondary mixture.

[0094] In this embodiment, for step S301: using polyethylene glycol diacrylate as the main matrix, when polyethylene glycol diacrylate and polyethylene glycol dimethacrylate are mixed, the ratio is 1:2; when polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, and polyethylene glycol methacrylate are mixed, the ratio is 1:(0.5~1):(1~3). All of the above polymers contain polyethylene glycol segments, and their ether oxygen (~O~) structure is similar to Li... + It possesses strong coordination ability and can serve as a "highway" for lithium-ion transport, providing high ionic conductivity. Simultaneously, the presence of the above mixture in a small proportion (1-5) ensures the formation of a moderately cross-linked network, guaranteeing mechanical strength while avoiding excessive cross-linking that hinders ion migration. Trifluoroethyl methacrylate is added at a mass ratio of (10-100). The introduced strongly electronegative fluorine atoms promote lithium salt dissociation through an inductive effect, enhancing ionic conductivity; furthermore, they can participate in the formation of a stable, LiF-rich interface film (SEI).

[0095] For step S302, lithium bis(trifluoromethanesulfonylimide) (LiTFSI) is introduced to provide lithium ions. The amount added is 13-20% of the mass of the primary mixture obtained in step S301. The extremely high lithium ion concentration can not only directly improve the ionic conductivity, but also form a more stable and effective protective layer at the electrode interface.

[0096] For step S303, a curing initiator is introduced, tetrahydrothiophene sulfone as a solvent or auxiliary agent for the "photo / thermal polymerization initiator", or it is itself a special initiator or accelerator.

[0097] Further, in step S400, the solid electrolyte precursor suspension is sprayed onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device, and the coating thickness is 10-50 μm. In this embodiment, the coating thickness is limited. If the coating is too thin (<10 μm), it may not completely cover the microscopic irregularities on the electrolyte substrate surface, forming a discontinuous interface layer, resulting in excessively high local current density, increasing interface impedance, and potentially inducing lithium dendrite formation. If the coating is too thick (>50 μm), although the coverage is better, the total path of ion transport in the solid electrolyte becomes longer. Since the ionic conductivity of solid electrolytes is generally lower than that of liquid electrolytes, an excessively thick layer will significantly increase the bulk impedance of the electrolyte, thereby reducing the rate performance of the battery. The advantage of 10-50 μm is that this thickness is sufficient to form a continuous, dense, and defect-free interface layer, ensuring perfect contact with the substrate.

[0098] Furthermore, in step S500, the pressure of the high-speed imprint is controlled between 400MPa and 600MPa, the temperature is controlled between 60 and 80°C, and the holding time is 5 to 60 minutes.

[0099] Further, in step S500, after isostatic hot pressing, the cell composite is dried in a vacuum environment at 78~82℃ for 10~14 hours. In this embodiment, drying is performed to remove residual moisture, solvents, and trace gases from the cell composite, reduce interfacial porosity and impurity interference, strengthen the tight bonding between the positive electrode, electrolyte, and negative electrode, reduce interfacial impedance, and avoid side reactions caused by residual impurities during subsequent charging and discharging, thereby improving the cell's ion conduction efficiency, cycle stability, and safety performance.

[0100] In this embodiment, the pressure of the high-speed imprinting is limited to ensure that the electrolyte coating adheres tightly to the electrode. The electrode and electrolyte surfaces are microscopically rough and porous. Under normal pressure, they are only in "point contact." The ultra-high pressure of 400-600 MPa can forcefully crush these microstructures, causing plastic deformation at the contact points, transforming "point contact" into "surface contact," greatly increasing the effective contact area and thus improving the composite quality. This pressure utilizes the characteristics of the non-Newtonian imprinted high-fluorine electrolyte matrix prepared in S200. Under extremely high shear forces, the viscosity of this matrix decreases sharply, exhibiting fluid-like behavior, flowing like a liquid and filling all the pores on the electrode surface. After the pressure is removed, the electrolyte layer on the matrix adheres tightly to the electrode with extremely strong bonding. Simultaneously, the temperature is limited to promote chemical reaction and fusion at the electrode-electrolyte interface. This temperature is higher than the glass transition temperature of many polymers (such as polyethylene oxide and polyvinylidene fluoride-hexafluoropropylene copolymer). Heating softens the polymer binder / matrix in the electrodes and electrolyte, enhancing chain segment mobility. This significantly reduces the force required for imprinting and makes it easier for the components to fuse into a single unit under pressure. Furthermore, limiting the holding time ensures structural stability and shaping.

[0101] To facilitate data comparison, the following three preferred embodiments of the present invention are provided, along with corresponding comparative embodiments.

[0102] Specifically, Embodiment 1 of the present invention includes the following steps:

[0103] Step 1: Prepare positive and negative electrode sheets;

[0104] Positive electrode sheet: High-nickel ternary positive electrode material (NCM811), conductive carbon black (SP), polyvinylidene fluoride (PVDF) binder, and Li6PS5Cl sulfide solid electrolyte powder are mixed at a mass ratio of 90:3:2:5. Using N-methylpyrrolidone (NMP) as a solvent, the slurry is uniformly coated onto aluminum foil using a wet process, and after vacuum drying at 120℃ for 12 hours, it is cut into the required size.

[0105] Negative electrode sheet: Silicon-carbon composite material (SiC), artificial graphite, polyacrylic acid (PAA) binder, and Li6PS5Cl sulfide solid electrolyte powder are mixed in a mass ratio of 15:60:3:22. A slurry is prepared using water as a solvent, coated onto copper foil, and then vacuum dried at 100°C for 12 hours before being cut for use.

[0106] Step 2: Preparation of a non-Newtonian imprinted high-fluorine electrolyte matrix;

[0107] Starch, polyvinylidene fluoride-hexafluoropropylene copolymer, and lithium difluorooxalate borate (LiDFOB) were mixed in a mass ratio of 50:15:15. This mixture was then added to 1,2-dimethoxyethane (DME) solvent and stirred thoroughly to generate the first electrolyte mixture. Subsequently, 8% (by mass) of fluoroethylene carbonate (FEC) was added to the first electrolyte mixture, and stirring continued for 30 minutes. The mixture was then transferred to a kneader and kneaded at 25°C for 30 minutes to shape the matrix. Finally, it was heated at 60°C for 2 hours.

[0108] Step 3: Prepare a solid electrolyte precursor suspension;

[0109] Strontium lanthanum titanate nanoparticles were prepared by mixing polyvinylidene fluoride-hexafluoropropylene copolymer with strontium lanthanum titanate nanoparticles at a mass ratio of 1:0.5, then dissolving them in N,N-dimethylformamide, and mechanically stirring at 65°C for 24 hours to obtain a uniformly dispersed suspension.

[0110] Step 4: Spraying and Fluorination;

[0111] The suspension obtained in step three was sprayed onto the surface of the electrolyte matrix obtained in step two using a high-speed spraying device, with the thickness controlled to be approximately 30 μm. It was then heated at 60 °C for 8 minutes to ensure complete fluorination of the interface.

[0112] Step 5: Imprinting and battery assembly;

[0113] The composite electrolyte layer obtained in step four is transferred onto the surface of the positive electrode using an imprinting device. The negative electrode is then stacked on top and subjected to isostatic pressing. The process parameters are: pressure 500 MPa, temperature 70°C, and holding time 30 minutes. Subsequently, it is vacuum dried at 80°C for 12 hours to completely remove residual solvent, and finally encapsulated to obtain an all-solid-state battery cell.

[0114] Example 2:

[0115] Step 1: Prepare positive and negative electrode sheets;

[0116] Cathode: A composite material consisting of lithium iron phosphate (LFP) cathode material, Ketjen black (KB), polyvinylidene fluoride (PVDF), and LLZTO (Li). 6.4 La3Zr 1.4 Ta 0.6 O 12 The oxide solid electrolyte powder was mixed at a mass ratio of 80:2:3:15. The subsequent process was the same as in Example 1.

[0117] Negative electrode: Pure artificial graphite is used as the active material, and is mixed with styrene-butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC-Na) binder, and lithium lanthanum zirconium tantalum (LLZTO) oxide solid electrolyte at a mass ratio of 92:2:2:4. Subsequent processes are the same as in Example 1.

[0118] Step 2: Preparation of a non-Newtonian imprinted high-fluorine electrolyte matrix;

[0119] The mass ratio of the first electrolyte mixture was adjusted to starch:polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP):lithium difluorooxalate borate (LiDFOB) = 40:10:20. 10% FEC (Fluoride Electrolyte) was added to the total mass of the first electrolyte mixture. The kneading temperature was controlled at 10°C to adjust the rheological properties of the matrix.

[0120] Step 3: Prepare a solid electrolyte precursor suspension;

[0121] Polyethylene glycol diacrylate (PEGDA) and trifluoroethyl methacrylate were mixed at a mass ratio of 1:20 and stirred thoroughly to obtain a primary mixture. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at 13% of the total mass of the primary mixture was added and stirred thoroughly to dissolve, forming a secondary mixture. Then, tetrahydrothiophene sulfone additive at 5% of the total mass of the secondary mixture was added and mixed evenly to obtain a solid electrolyte precursor suspension.

[0122] Step 4: Spraying and Fluorination;

[0123] The solid electrolyte precursor suspension obtained in step three is sprayed onto the electrolyte substrate obtained in step two, with a thickness controlled at 20 μm. The substrate is then heated at 60°C for 10 minutes.

[0124] Step 5: Imprinting and battery assembly;

[0125] The isostatic hot pressing process parameters were adjusted to: pressure 450 MPa, temperature 65°C, and holding time 45 minutes. Subsequent drying and packaging steps were the same as in Example 1.

[0126] Example 3:

[0127] Step 1: Prepare positive and negative electrode sheets;

[0128] Positive electrode: Lithium iron manganese phosphate (LFMP) and lithium cobalt oxide (LCO) are compounded at a mass ratio of 1:1, and mixed with a conductive agent (vapor-grown carbon fiber), a binder (polytetrafluoroethylene), and a lithium indium trichloride (Li3InCl6) halide solid electrolyte at a mass ratio of 70:5:3:22. The mixture is then directly laminated onto aluminum foil using a dry process.

[0129] Negative electrode: Silicon suboxide (SiO), artificial graphite, polyimide (PI) binder, and Li3InCl6 halide solid electrolyte are mixed at a mass ratio of 30:45:5:20. Subsequent wet process is the same as in Example 1.

[0130] Step 2: Preparation of a non-Newtonian imprinted high-fluorine electrolyte matrix;

[0131] The ratio was adjusted to starch:polytetrafluoroethylene:lithium difluorooxalate borate = 55:18:12. 6% by weight of fluoroethylene carbonate was added. Kneading was carried out at 40°C.

[0132] Step 3: Prepare a solid electrolyte precursor suspension;

[0133] Polyethylene oxide (PEO) and lanthanum strontium titanate (LSTO) were dissolved in acetonitrile at a mass ratio of 1:0.1 and stirred to obtain a suspension.

[0134] Step 4: Spraying and Fluorination;

[0135] The coating thickness should be controlled at 40μm. Heat at 60℃ for 5 minutes.

[0136] Step 5: Imprinting and battery assembly;

[0137] The three-layer stack (positive electrode-electrolyte-negative electrode) is then subjected to isostatic pressing. The process parameters are: pressure 600 MPa, temperature 80℃, and holding time 15 minutes.

[0138] Comparative Example 1:

[0139] Compared to Example 1 above, there is no solid electrolyte precursor coating, and steps three and four are omitted. In step five, the non-Newtonian imprinted high-fluorine electrolyte substrate prepared in step two is directly imprinted onto the positive electrode sheet, and then the negative electrode is stacked and hot-pressed.

[0140] Comparative Example 2:

[0141] Compared to Example 1 above, step two is omitted, and a rigid plate is directly used to replace the non-Newtonian fluid high-fluorine electrolyte matrix.

[0142] Comparative Example 3:

[0143] Compared to Example 1 above, in step one, no solid electrolyte powder is added to the formulations of the positive and negative electrodes.

[0144] The cathode formula was changed to nickel-cobalt-manganese ternary cathode material (NCM811): superconducting carbon black: polyvinylidene fluoride = 92:5:3.

[0145] The negative electrode formulation was changed to silicon-carbon composite negative electrode material (SiC): graphite: polyacrylic acid (PAA) = 20:75:5.

[0146] The remaining steps are exactly the same as in Example 1.

[0147] Comparative Example 4:

[0148] Compared to Example 1 above, in step five of this comparative example, the pressure of the isostatic hot pressing is reduced from 500 MPa to 100 MPa. The remaining steps are exactly the same as in Example 1.

[0149] Comparative Example 5:

[0150] Compared to Example 1 above, in the preparation of the positive electrode in step one of this comparative example, polyethylene oxide (PEO), which is unstable to sulfide electrolytes, is used as a binder instead of PVDF. The formulation is nickel-cobalt-manganese ternary positive electrode material NCM811: superconducting carbon black (SP): polyethylene oxide (PEO): Li6PS5Cl = 90:3:2:5. The remaining steps are exactly the same as in Example 1.

[0151] Table 1: Comparison of Coulomb efficiency and capacity retention data

[0152]

[0153] The experimental data above were obtained through standardized charge-discharge cycle tests on the batteries produced in the above embodiments and comparative examples. The experimental data provided in Table 1 strongly demonstrates the cell composite preparation method proposed in this invention and its various core technical features, resulting in significant and synergistic beneficial effects. These effects are mainly reflected in the leaps in interface stability, cycle life, and overall electrochemical performance.

[0154] The three embodiments described above all exhibited the following after 100 cycles:

[0155] The ultra-high coulombic efficiency (>99.5%) indicates that there are very few side reactions during the charging and discharging process of the battery, and the lithium-ion insertion and extraction process is highly reversible.

[0156] The extremely high capacity retention (>98%) indicates that the battery active materials are effectively protected and the electrode structure (especially the silicon-based anode undergoing volume changes) and interface are very stable.

[0157] By comparing the data of the comparative example and the embodiment, the following beneficial effects can be obtained:

[0158] 1. Solid electrolyte precursor suspension interface layer: compared with Comparative Example 1, the following was obtained:

[0159] Beneficial effects: Significantly improves interfacial compatibility and stability, and reduces side reactions.

[0160] Data support: Comparative Example 1, lacking this layer, exhibits significantly lower coulombic efficiency (96.67%) and capacity retention (89.92%) compared to Example 1 (99.97%) and capacity retention (100.5%). (See also...) Figure 3 and Figure 4 It can be seen that the battery resistance of Example 1 under different imprinting forces is significantly lower than that of Comparative Example 1, while the cycle performance is significantly better than that of Comparative Example 1.

[0161] Mechanism of action: This suspension layer, through spraying and fluorination, forms a dense, stable, and ion-conducting transition layer between the electrolyte substrate and the electrode. It perfectly fills microscopic defects and optimizes the interfacial environment through chemical bonding, thereby significantly reducing interfacial impedance and suppressing side reactions and lithium dendrite growth during cycling.

[0162] 2. Non-Newtonian imprinted high-fluorine electrolyte matrix: Compared with Comparative Example 2, the following was obtained:

[0163] Beneficial effects: Achieves extremely close contact with the electrodes, constructing a stable mechanical interlocking structure.

[0164] Data support: Comparative Example 2, which uses a rigid matrix, showed worse performance compared to Example 1, with lower coulombic efficiency (95.33%) and capacity retention (87.60%) than the data from Example 1.

[0165] Mechanism of action: Its non-Newtonian properties give it excellent fluidity under high pressure, allowing it to encapsulate and embed electrode particles like a liquid; after the pressure is removed, it returns to a solid state, forming a "mortise and tenon structure". This active adaptation rather than passive contact creates unparalleled interfacial contact area and binding force, ensuring the unobstructed ion channels and long-term structural stability.

[0166] 3. Construction of an ion-conducting network inside the electrode: Compared with Comparative Example 3, the following results were obtained:

[0167] Beneficial effects: This is the foundation for achieving efficient operation of the entire battery and is the most significant technical feature.

[0168] Data support: Comparative Example 3, which does not add solid electrolyte to the electrode, shows a sharp deterioration in performance data. Specifically, its coulombic efficiency (80.12%) and capacity retention (61.26%) are much lower than those of Example 1 above.

[0169] Mechanism of action: A solid electrolyte is incorporated into the electrode, constructing a three-dimensional ion-conducting network that runs through the electrode. Without a solid electrolyte, this ion-conducting network cannot be formed, resulting in ineffective lithium-ion transport to the electrode interior. Consequently, most of the active material cannot participate in the reaction, leading to extremely low initial capacity and rapid capacity decay. This addresses the ion transport problem at its root.

[0170] 4. High-pressure embossing process: Compared with Comparative Example 4, the results are as follows:

[0171] Beneficial effect: Providing the driving force for achieving a perfect interface integration is key to the success of the process.

[0172] Supporting data: Comparative Example 4, with pressure reduced to 100 MPa, showed a decrease in coulombic efficiency (91.32%) and capacity retention (82.66%) compared to the performance data of Example 1.

[0173] Mechanism of action: The ultra-high pressure of 400~600MPa is a necessary condition to force the various components (electrodes, interface layer, electrolyte matrix) to undergo plastic deformation and close fusion. Low pressure cannot overcome the strength of the material itself, cannot achieve effective mechanical interlocking and low impedance interface, resulting in poor contact and rapid failure.

[0174] 5. Compatible chemical system: Compared with Comparative Example 5, the following was obtained:

[0175] Beneficial effects: Ensures the chemical stability of the entire battery system and prevents damage between components.

[0176] Supporting data: Comparative Example 5, which uses an incompatible binder, showed a decrease in coulombic efficiency (95.32%) and capacity retention (91.21%) compared to the performance data of Example 1.

[0177] Mechanism of action: PEO undergoes unfavorable chemical side reactions with the sulfide electrolyte, disrupting the electrolyte structure and increasing interfacial impedance. This demonstrates that the advantages of this invention depend on careful consideration and design regarding the chemical compatibility of each component material.

[0178] In summary, the preferred embodiments of the present invention improve the composite quality and efficiency between the electrolyte layer and the electrode sheet and reduce the interfacial impedance by using a non-Newtonian imprinted high-fluorine electrolyte substrate coated with an electrolyte layer, a fluorinated protective layer, and imprinting and hydrostatic pressing processes.

[0179] This invention also discloses a battery cell composite, obtained using the aforementioned method, comprising a positive electrode, a negative electrode, and a composite electrolyte layer disposed between the positive and negative electrode. The composite electrolyte layer is a non-Newtonian imprinted high-fluorine electrolyte substrate with a fluorinated electrolyte layer coated on its surface. Because the battery cell composite is obtained using the aforementioned method, it possesses all the beneficial effects of products manufactured using the method described above.

[0180] The present invention also discloses an all-solid-state battery, comprising the above-described cell composite. Because the all-solid-state battery comprises the above-described cell composite, it possesses all the beneficial effects of the cell composite described above.

[0181] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a battery cell composite, characterized in that, Includes the following steps: S100: The positive and negative electrode sheets for preparing all-solid-state batteries; S200: Preparation of non-Newtonian imprinted high-fluorine electrolyte matrix; Step S200 includes the following steps: S201: Fluorine-containing polymer, starch and lithium difluorooxalate borate are mixed and then added to a mixed solvent of methyl nylonate and dimethyl ether. The mixture is stirred thoroughly to generate the first electrolyte mixture. The mass ratio of fluorine-containing polymer, starch and lithium difluorooxalate borate is (5~20):(30~60):(10~20). The fluorine-containing polymer is polyvinylidene fluoride-hexafluoropropylene copolymer or polytetrafluoroethylene. S202: Add 5-10% of the total mass of the first electrolyte mixture to the first electrolyte mixture and stir to generate the second electrolyte mixture; S203: Transfer the second electrolyte mixture to a kneader and knead for 5~60 minutes to form the second electrolyte mixture into an electrolyte matrix. The temperature range during kneading is -20℃~60℃. S204: The electrolyte matrix is ​​heated at 60°C for 2 hours to obtain a non-Newtonian imprinted high-fluorine electrolyte matrix; S300: Preparation of solid electrolyte precursor suspension; S400: The solid electrolyte precursor suspension is sprayed onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device, and then heated at 60°C for 5~10 minutes to fully fluorinate the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate by the solid electrolyte precursor suspension, forming a fluorinated electrolyte layer. S500: The fluorinated electrolyte layer formed on the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate is imprinted onto the positive electrode sheet at high speed. Then, the negative electrode sheet is stacked on the other side of the non-Newtonian imprinted high-fluorine electrolyte substrate and isostatically hot-pressed to solidify the electrolyte layer and generate a cell composite.

2. The method for preparing the cell composite according to claim 1, characterized in that, S100 includes the following steps: S101: Any one or more of the following high-nickel ternary cathode powder, lithium iron phosphate cathode powder, lithium manganese iron phosphate cathode powder, and lithium cobalt oxide cathode powder are mixed with conductive agent, binder, and solid electrolyte in a mass ratio of (65~93.5):(1~5):(0.5~2):(5~33.5) to form a mixed powder, which is then coated on aluminum foil or composite current collector and dried to obtain a cathode sheet; S102: One or more of silicon-carbon, silicon suboxide, nano-silicon, and micron-silicon are mixed with graphite, binder, and solid electrolyte in a mass ratio of (0~70):(0~70):(2~5):(5~30), coated onto the surface of copper foil or composite current collector, and then dried to obtain a negative electrode sheet.

3. The method for preparing the cell composite according to claim 1, characterized in that, Step S300 includes the following steps: S301: Tetrabutyl titanate is mixed with citric acid and ethylene glycol to obtain a mixed solution. Then, La(NO3)3·6H2O and Sr(NO3)2 are dissolved in the mixed solution according to a preset molar ratio and stirred continuously to obtain a preliminary mixed solution. S302: Heat the preliminary mixture in a water bath at 60~120℃ and stir until a gel is formed; S303: Dry the gel at 200~300℃ for 2~4 hours to remove organic components and nitrates, and obtain the precursor powder; S304: After pulverizing the precursor powder, sinter it at 700~1000℃ for 5~12 hours to obtain the raw material; S305: Ball milling of raw materials to prepare lanthanum strontium titanate nanoparticles; S306: One or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polymethyl methacrylate, and polyacrylonitrile, along with strontium lanthanum titanate nanoparticles, are dissolved in N,N-dimethylformamide and mechanically stirred at 65°C for 24 hours to obtain a uniformly dispersed solid electrolyte precursor suspension.

4. The method for preparing the cell composite according to claim 1, characterized in that, Step S300 includes the following steps: S301: A primary mixture is prepared by mixing one or more of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate and polyethylene glycol methacrylate with trifluoroethyl methacrylate in a mass ratio of (1~5):(10~100). S302: Add lithium bis(trifluoromethanesulfonyl)imide to the primary mixture, stir thoroughly to dissolve, and mix completely to obtain a secondary mixture. The mass of lithium bis(trifluoromethanesulfonyl)imide added is 13-20% of the primary mixture. S303: Add tetrahydrothiophene sulfone to the secondary mixture and mix thoroughly to obtain a solid electrolyte precursor suspension, wherein the mass of tetrahydrothiophene sulfone added is 2~7% of the secondary mixture.

5. The method for preparing the cell composite according to claim 1, characterized in that, In step S400, the coating thickness formed by spraying the solid electrolyte precursor suspension onto the surface of the non-Newtonian imprinted high-fluorine electrolyte substrate using a high-speed spraying device is 10~50μm.

6. The method for preparing the cell composite according to claim 1, characterized in that, In step S500, the isostatic hot pressing pressure is 400MPa~600MPa, the temperature is 60~80℃, and the holding time is 5~60min.

7. The method for preparing the cell composite according to claim 1, characterized in that, In step S500, after isostatic hot pressing, the cell composite is dried in a vacuum environment at 78~82℃ for 10~14h.

8. A battery cell composite, characterized in that, The battery cell composite is prepared by any one of the preparation methods of claims 1 to 7, comprising a positive electrode, a negative electrode, and a composite electrolyte layer disposed between the positive electrode and the negative electrode, wherein the composite electrolyte layer is a non-Newtonian imprinted high-fluorine electrolyte substrate with a fluorinated electrolyte layer coated on its surface.

9. An all-solid-state battery, characterized in that, Includes the cell composite as described in claim 8.

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