All-solid-state lithium ion battery and preparation method thereof

Abstract

The invention provides an all-solid-state lithium ion battery and a preparation method thereof, and the preparation method comprises the following steps: dissolving polysulfone resin in an organic solvent, adding an inorganic filler, and heating to 150 DEG C to obtain a polysulfone-based composite electrolytic material; mixing and heating a sulfur source and a phosphorus source to form a sulfur-phosphorus compound, coating a positive electrode substrate with the sulfur-phosphorus compound, and heating to obtain a positive electrode plate; and attaching a negative electrode plate and the positive electrode plate to two opposite sides of the polysulfone-based composite electrolytic material, heating to 180 DEG C, and carrying out hot pressing to obtain the all-solid-state lithium ion battery. Therefore, the thermal stability and the service life of the all-solid-state lithium ion battery are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and particularly relates to an all-solid-state lithium-ion battery and a preparation method thereof. Background Art

[0002] The electrolyte used in traditional liquid electrolyte lithium-ion batteries is liquid, which is unstable at high temperatures, making lithium-ion batteries have the risk of combustion and explosion. To solve the potential safety problems of traditional liquid electrolyte lithium-ion batteries, researchers have focused on solid electrolytes. All-solid-state lithium-ion batteries have emerged. Compared with traditional liquid electrolytes, solid electrolytes, with their excellent electrochemical stability, thermal stability and non-flammability, enable operation at high temperatures and effectively prevent battery combustion or explosion.

[0003] However, an all-solid-state lithium-ion battery is composed of multiple layers of materials stacked (negative electrode / electrolyte / positive electrode), and there are significant differences in the thermal expansion coefficients of each layer. At high temperatures, the size changes of each layer are inconsistent, which will cause significant stress concentration at the interface, resulting in deformation, cracking or peeling, leading to poor thermal stability of the all-solid-state lithium-ion battery. During thermal cycling (heating / cooling repeatedly) or continuous high temperature, the microcracks in the electrolyte layer are prone to spread, and the effective contact area between the electrode and the electrolyte decreases, resulting in an increase in interface impedance and a subsequent attenuation of battery life. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an all-solid-state lithium-ion battery and a preparation method thereof, aiming to solve the problem of battery life attenuation caused by poor thermal stability of all-solid-state lithium-ion batteries.

[0005] To solve the above problems, the present invention proposes a preparation method for an all-solid-state lithium-ion battery, and the steps include: S1. Dissolve a polysulfone resin in an organic solvent, add an inorganic filler, and heat to 150 °C to obtain a polysulfone-based composite electrolyte material; S2. Mix and heat a sulfur source and a phosphorus source to form a sulfur-phosphorus composite, coat the sulfur-phosphorus composite on a positive electrode substrate, and heat to obtain a positive electrode sheet; S3. Attach a negative electrode sheet and the positive electrode sheet to opposite sides of the polysulfone-based composite electrolyte material, and heat to 180 °C for hot pressing to obtain the all-solid-state lithium-ion battery.

[0006] In some embodiments of the present invention, in step S1, the polysulfone resin includes at least one of polyphenylsulfone, polyethersulfone, and polychlorosulfonated benzene, the organic solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, and chloroform, and the inorganic filler includes at least one of lithium fluorophosphate, calcium titanate, and lithium fluoride.

[0007] In some embodiments of the present invention, step S1 includes: S1.1. Add a polysulfone resin to an organic solvent and stir it at room temperature using a stirring device. Continuously stir for 2 to 4 hours to ensure that the polysulfone resin is completely dissolved into a homogeneous solution until the polysulfone resin is completely dissolved; S1.2. Add an inorganic filler to the dissolved polysulfone resin and mix it at room temperature using a high-shear mixer. The mixing process lasts for 30 to 60 minutes to obtain a composite solution; S1.3. Place the composite solution in an inert atmosphere, heat it to 150 °C and hold for 2 hours. After heating, perform hot pressing. The stress of the hot pressing is 2 to 5 MPa, and the hot pressing time is 10 to 20 minutes. After cooling, a polysulfone-based composite electrolytic material is obtained.

[0008] In some embodiments of the present invention, in step S2, the sulfur source includes at least one of lithium sulfide and phosphorus pentasulfide, the phosphorus source includes at least one of aluminum dihydrogen phosphate and lithium phosphorus sulfide, and the positive electrode substrate includes at least one of aluminum foil, copper foil, and titanium alloy foil.

[0009] In some embodiments of the present invention, step S2 includes: S2.1. Ball-mill and mix the sulfur source and the phosphorus source, then transfer them to a high-temperature reaction furnace, heat to 200 °C under the protection of nitrogen or argon, and hold for 3 hours to obtain a sulfur-phosphorus composite; S2.2. Mix the sulfur-phosphorus composite powder with an adjusting solvent to make an electrode paste, evenly coat it on the positive electrode substrate using a coater, and then heat to 300 °C and hold for 2 hours for drying to obtain a positive electrode sheet, where the coating thickness of the electrode paste is 50 to 100 μm.

[0010] In some embodiments of the present invention, calculated by mass ratio, the sulfur source: the phosphorus source = (2 to 2.5): 1.

[0011] In some embodiments of the present invention, step S3 includes: S3.1. Stack the polysulfone-based composite electrolytic material and the negative electrode sheet on the positive electrode sheet in sequence, transfer them to a flat mold of a hot press, slowly heat to 180 °C, apply a stress of 2 to 5 MPa while heating, maintain for 10 to 30 minutes, slowly cool to room temperature after hot pressing, and gradually release the pressure to obtain a battery core; S3.2. Use an aluminum-plastic film or a metal shell to seal the battery core to obtain the all-solid-state lithium-ion battery.

[0012] In some embodiments of the present invention, in step S3, the negative electrode sheet includes at least one of a lithium metal foil and a lithium titanate negative electrode sheet.

[0013] In some embodiments of the present invention, the cooling control equation of the battery cell is as follows: Wherein, represents the temperature of the battery cell at time , with the unit of °C, represents the ambient temperature, with the unit of °C, represents a constant characterizing the heat transfer coefficient, and k is 0.02 to 0.10 , represents the maximum allowable cooling rate, is 5 to 10 °C / min, represents the cooling rate of the battery cell, with the unit of °C / min.

[0014] The present invention provides a all-solid-state lithium-ion battery, which is made by the preparation method of a all-solid-state lithium-ion battery as described above. The all-solid-state lithium-ion battery includes a polysulfone-based composite electrolyte material, a positive electrode sheet, and a negative electrode sheet; wherein, is used to provide a lithium ion transfer channel; The positive electrode sheet is used to exchange lithium ions with the negative electrode during charge and discharge; The negative electrode sheet is used to achieve reciprocating insertion and extraction of lithium ions with the positive electrode.

[0015] In some embodiments of the present invention, the step S3 includes: Compared with the prior art, the all-solid-state lithium-ion battery and its preparation method in the present invention have the following beneficial effects: Polysulfone resins such as polyphenylsulfone, polyethersulfone, or polychlorosulfonated benzene are used. These polymers themselves have relatively high glass transition temperatures and decomposition temperatures, and can maintain good mechanical strength and structural integrity at high temperatures. By performing melting or cross-linking treatment at high temperatures, the denseness and high-temperature resistance of the polysulfone matrix are further enhanced. Adding inorganic fillers to the polysulfone solution and making them form a firm bond with the polysulfone matrix during heating and hot pressing can significantly reduce the softening or deformation of the polymer at high temperatures, and improve the mechanical strength and chemical stability throughout the electrolyte, reducing the interfacial stress caused by the difference in the thermal expansion coefficients of the materials. The interface between the thermally stable sulfur-phosphorus composite and the positive electrode substrate completes bonding or mild solid-phase reaction in this temperature range, forming a stable sulfur-phosphorus compound and firmly adhering to the positive electrode substrate. At the same time, the interfacial adhesion with the polysulfone-based composite electrolyte material is enhanced, the interfacial impedance is reduced, the cracking risk caused by the difference in thermal expansion and contraction is reduced, the thermal stability of the all-solid-state lithium-ion battery is improved, and its cycle life in a high-temperature environment is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a schematic flow chart of the preparation method of a all-solid-state lithium-ion battery in an embodiment of the present invention. Detailed implementation manners

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] Please refer to Figure 1 , the present invention provides a preparation method of an all-solid-state lithium-ion battery, and the steps include: S1. Dissolve a polysulfone resin in an organic solvent, add an inorganic filler, and then heat to 150 °C to obtain a polysulfone-based composite electrolyte material.

[0019] In step S1, the polysulfone resin includes at least one of polyphenylsulfone, polyethersulfone, and polychlorosulfonated benzene, the organic solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, and chloroform, and the inorganic filler includes at least one of lithium fluorophosphate, calcium titanate, and lithium fluoride.

[0020] Step S1 includes: S1.1. Add the polysulfone resin to the organic solvent and stir it at room temperature using a stirring device. Keep stirring for 2 to 4 hours to ensure that the polysulfone resin is completely dissolved into a uniform solution until the polysulfone resin is completely dissolved.

[0021] By stirring for a long time and sufficiently, dissolving polysulfone resins such as polyphenylsulfone, polyethersulfone or polychlorosulfonated benzene into solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and chloroform, a uniform and stable solution can be obtained at the molecular level. This lays a foundation for the subsequent mixing with inorganic fillers, reduces the agglomeration phenomenon caused by the local undissolved polymer. It improves the uniformity and mechanical strength of the final composite material, which is beneficial to the subsequent ionic conductivity and interfacial stability. Slowly stirring and maintaining sufficient time at room temperature can prevent the polymer from precipitating or gelling due to insufficient local dissolution. Ensure better dispersion in the subsequent mixing stage, reduce process instability factors. Provide a good starting point for further improving the uniform cross-linking of the electrolyte at high temperature.

[0022] S1.2. Add the inorganic filler to the dissolved polysulfone resin and mix it at room temperature using a high-shear mixer. The mixing process lasts for 30 to 60 minutes to obtain a composite solution.

[0023] The use of a high-shear mixer can fully disperse inorganic fillers such as lithium fluorophosphate, calcium titanate, and lithium fluoride in the polysulfone solution in a short time. This avoids uneven local ionic conductivity caused by powder agglomeration, improves the overall conductivity of the material, strengthens the interaction between the polysulfone matrix and the inorganic particles, and prepares for the subsequent cross-linking / thermal pressing to form a dense structure. The uniform dispersion of inorganic fillers in the matrix can endow the composite material with higher mechanical strength and thermal stability characteristics, and enhance its structural retention ability in high-temperature environments. It also improves the high-temperature resistance characteristics and deformation maintenance ability of the electrolyte, avoiding cracking caused by differences in thermal expansion coefficients, and endows the material with higher chemical / physical stability, laying the foundation for the use of the electrolyte at higher voltages or in more severe environments.

[0024] The calculation formula for the filling rate of inorganic fillers is: ; represents the filling rate (%) of inorganic fillers in the polysulfone-based composite electrolyte material. The higher the value, the greater the embedding efficiency of inorganic fillers per unit volume or unit concentration under the same mass. can be 10% - 50%.

[0025] represents the mass fraction (dimensionless) of inorganic fillers in the composite solution (i.e., polysulfone solution + inorganic fillers).

[0026] represents the density (g·mL⁻¹) of the composite solution, which can be obtained by a hydrometer or a density measuring instrument.

[0027] represents the volume (mL) of the composite solution.

[0028] represents the mass (g) of the polysulfone resin used in the preparation of the composite solution. In step S1.2, after adding inorganic fillers to the dissolved polysulfone solution and performing high-shear mixing, the density of the mixed system can be sampled and measured as well as the mass fraction of inorganic fillers in the composite solution , combined with the known mass of the polysulfone resin and the volume of the composite solution , the filling rate of inorganic fillers can be calculated .

[0029] If this value is larger, it means that in the same polymer matrix, more inorganic fillers are actually dispersed and stably combined, which is beneficial to improving the mechanical strength, ionic conductivity, and thermal stability of the final polysulfone-based composite electrolyte material.

[0030] It refers to the filler content measured in the composite solution. However, during the subsequent processes of solvent evaporation, hot pressing, or sintering, the concentration of inorganic fillers cannot accurately reflect the actual proportion. The filling rate more intuitively represents the proportion of inorganic fillers that are actually embedded and retained relative to the overall mass, which is of guiding significance for the performance of the final all-solid-state lithium-ion battery.

[0031] On the premise of meeting the necessary mechanical strength, the mass of polysulfone resin can be appropriately reduced , so that the inorganic fillers account for a larger proportion in the whole. Pre-dispersion or hierarchical mixing can also be carried out first, allowing a small amount of polysulfone resin to coat more inorganic fillers first, and then gradually adding the remaining polymer to adjust the viscosity. By selecting appropriate solvents, using high-shear dispersion, vacuum degassing and other means, the bubbles in the solution can be reduced, the fillers can be dispersed more evenly, and the overall density can be increased , thereby increasing the filling rate of inorganic fillers.

[0032] S1.3. Place the composite solution in an inert atmosphere, heat it to 150 °C and hold for 2 hours. After heating, perform hot pressing with a stress of 2 - 5 MPa and a hot pressing time of 10 - 20 minutes. After cooling, a polysulfone-based composite electrolyte material is obtained.

[0033] During the 2-hour heat preservation at 150 °C, the interfacial interaction between the polysulfone matrix and the inorganic fillers is enhanced, and at the same time, the solvent gradually volatilizes, and the residual gas or solvent is discharged. The polysulfone undergoes moderate cross-linking or melt flow at high temperature, which can coat and fix the inorganic particles, and finally form a more stable skeleton structure. The porosity inside the material is greatly reduced, the continuity of the ion transport channels is improved, and thus the overall ionic conductivity is enhanced. Performing hot pressing under an inert atmosphere (such as nitrogen or argon) can further remove pores and make the composite material layers bond tightly in a short time. It reduces oxidation or degradation caused by the participation of air or moisture, ensuring the purity of the material. It improves the mechanical strength and heat resistance of the electrolyte film, and reduces the interfacial impedance during subsequent use. The material after hot pressing slowly solidifies during the cooling process, stabilizing the interfacial bonding between the resin and the inorganic fillers. It prevents internal stress concentration or crack generation caused by rapid cooling, ensuring the overall uniformity and density of the material. A polysulfone-based composite electrolyte with excellent thermal stability, good mechanical strength and high ionic conductivity is formed, laying a foundation for achieving high safety and high performance in all-solid-state lithium-ion batteries in the future.

[0034] In one embodiment, the polysulfone-based composite electrolyte material is placed in a vacuum / inert gas atmosphere environment, and an aerosol-type lithium phosphate precursor solution or an ionic liquid containing a lithium salt is introduced for impregnation within the temperature range of 120 to 150 °C for 30 to 60 minutes. Subsequently, the temperature is raised to 180 to 200 °C to evaporate the residual solvent and promote chemical bonding, obtaining a secondary-modified polysulfone-based composite electrolyte material. The aerosol or ionic liquid can form additional ion transport channels at the micro pores / interfaces, improving the ionic conductivity of the electrolyte; at a higher temperature, the modifier undergoes a bonding reaction with the surface of the polysulfone / inorganic filler, enhancing the mechanical toughness and thermal stability, forming a more uniform and dense composite structure, reducing microcracks and the risk of deformation at subsequent high temperatures.

[0035] S2. Mix the sulfur source and the phosphorus source and heat them to form a sulfur-phosphorus composite, coat the sulfur-phosphorus composite on the positive electrode substrate, and obtain the positive electrode sheet after heating. In step S2, the sulfur source includes at least one of lithium sulfide and diphosphorus pentasulfide, the phosphorus source includes at least one of aluminum dihydrogen phosphate and lithium phosphorus sulfide, and the positive electrode substrate includes at least one of aluminum foil, copper foil, and titanium alloy foil. Calculated by mass ratio, sulfur source:phosphorus source = (2 to 2.5):1.

[0036] Step S2 includes: S2.1. Ball-mill and mix the sulfur source and the phosphorus source, then transfer them to a high-temperature reaction furnace, heat to 200 °C under the protection of nitrogen or argon, and hold for 3 hours to obtain the sulfur-phosphorus composite.

[0037] The ball-milling process can significantly improve the uniformity of the solid-phase reaction, enabling the sulfur source and the phosphorus source to achieve good contact at the micro scale, avoiding uneven dispersion of the raw materials during subsequent heating. It reduces the particle size and increases the specific surface area, providing more reactive sites for the subsequent high-temperature reaction, and improving the purity and uniformity of the sulfur-phosphorus composite. Under the protection of nitrogen or argon, the ball-milled mixture is heated to 200 °C and held at a constant temperature for 3 hours to cause a solid-phase or partial melting-solid-phase reaction between the sulfur source and the phosphorus source, generating a stable sulfur-phosphorus composite. It promotes the formation of the sulfur-phosphorus composite from the sulfur source and the phosphorus source, improving the activity and thermal stability of the material in subsequent electrochemistry. The inert atmosphere prevents oxidation or moisture intrusion, ensuring the chemical purity and structural integrity of the product. The finally obtained sulfur-phosphorus composite can provide a high capacity and excellent cycle life in the battery.

[0038] S2.2. Mix the sulfur-phosphorus composite powder and the conditioning solvent to make an electrode slurry, uniformly coat it on the positive electrode substrate using a coater, and then heat to 300 °C and dry for 2 hours to obtain the positive electrode sheet, where the coating thickness of the electrode slurry is 50 to 100 μm.

[0039] Maintain the dispersed state of the sulfur-phosphorus composite, enabling the active material to form a coatable fluid system in the slurry. The organic solvent helps the slurry spread evenly on the positive electrode substrate (such as aluminum foil, copper foil, titanium alloy foil), improving the film-forming quality and reducing defects. The coating thickness is moderate, which can balance the active material content and the ion / electron transport distance, increasing the battery capacity while reducing the transport impedance. The uniform thickness reduces the uneven reaction caused by local over-thickness or under-thickness, improving the overall consistency of the battery. At high temperatures, the binding between the sulfur-phosphorus composite and the substrate is tighter, enhancing the adhesion and interface stability between the material and the substrate. Remove the residual solvent and further cure the sulfur-phosphorus composite to form a positive electrode coating with good conductive and ion transport channels. Improve the high-temperature performance and enhance the long-term stability and cycle life of the positive electrode active material during charge and discharge. Uniformly coat the sulfur-phosphorus composite on the positive electrode substrate and dry and shape it at high temperatures to ensure a tight bond between the active material and the current collector (positive electrode substrate); the appropriate coating thickness and sufficient drying form a dense and uniform positive electrode film layer, effectively enhancing the electrochemical activity and cycle durability.

[0040] In one embodiment, when ball-milling the sulfur source and the phosphorus source, add the same metal powder as the positive electrode substrate (such as aluminum powder, copper powder, titanium alloy powder).

[0041] The ball-milling process enables the metal powder to have sufficient contact or local embedding with the sulfur-phosphorus composite at the microscale. When the subsequent material is coated on the same metal substrate (aluminum, copper, or titanium alloy), these metal powders can form "bridges" to further extend and tightly connect the conductive channels between the sulfur-phosphorus active material and the substrate. This not only reduces the impedance of charge transport but also reduces the side reactions or voids that may occur due to the direct contact between the metal substrate and the sulfur-phosphorus composite.

[0042] During ball milling, the metal powder is dispersed on the surface or inside of the sulfur-phosphorus composite particles to form a local composite area. This process allows the "metal powder-sulfur-phosphorus material" to produce better solid-phase bonding or mild sintering effects during subsequent coating, heating or hot pressing, making the adhesion between the entire positive electrode film layer and the metal substrate stronger. This reduces the local bulging, peeling or cracking of the electrode film that may occur during the charge-discharge cycle or thermal cycle. The same metal powder and the substrate are more matched in terms of thermal expansion and contraction, and can adapt to deformation together during high-temperature coating or subsequent heat treatment (such as 200-300°C or even higher) to reduce interfacial thermal stress. This is of great significance for improving the deformation stability of the electrode under high temperature or long-term cycle environments. During ball milling, the metal powder is "broken" and dispersed between the sulfur-phosphorus composites, which can help break up some of the agglomerated sulfur-phosphorus particles and make the positive electrode material more evenly distributed. When the slurry is coated on the same metal current collector, the active material forms a uniform mixture as a whole, reducing the electrochemical inhomogeneity generated in local sulfur-rich areas or metal-rich areas. The same metal powder provides a transition layer or bonding bridge between the positive electrode substrate and the sulfur-phosphorus composite, which is beneficial to reduce polarization, increase the effective reaction area, and show more stable discharge capacity and better rate performance in the cycle.

[0043] S3, attaching a negative electrode sheet and a positive electrode sheet to opposite sides of the polysulfone-based composite electrolytic material, heating to 180° C. for hot pressing, and obtaining an all-solid-state lithium-ion battery. The negative electrode sheet includes at least one of a lithium metal foil and a lithium titanate negative electrode sheet.

[0044] Step S3 includes: S3.1. Stack the polysulfone-based composite electrolytic material and the negative electrode sheet on the positive electrode sheet in sequence, transfer them to the flat mold of the hot press, slowly heat them to 180°C, apply 2-5MPa stress while heating, maintain for 10-30 minutes, slowly cool them to room temperature after hot pressing, and gradually release the pressure to obtain a battery core.

[0045] Active electrode materials (especially metal lithium negative electrodes or other easily oxidized components) remain chemically stable in an inert environment, reducing side reactions or interface degradation. This effectively prevents dust or other pollutants from accumulating at the electrode / electrolyte interface, thereby improving the bonding degree of the interface after subsequent hot pressing and improving battery performance.

[0046] The negative electrode sheet, polysulfone-based composite electrolytic material, and positive electrode sheet are strictly aligned to ensure that a uniform multilayer structure is formed during subsequent hot pressing. Ensuring the alignment between the electrodes can make the entire battery structure evenly stressed during the hot pressing process, avoiding local deformation or gaps. Ensure that the ion transmission path is simple and the interface impedance is low.

[0047] Under hot pressing conditions, polysulfone resins will flow or soften moderately at high temperatures, fill the interface micropores, improve the interface bonding force and reduce the interface impedance. Hot pressing removes residual voids and solvent molecules to obtain a solid composite electrolyte layer with higher density and uniformity. Under the action of external force, the layers will form a firm bond, reducing interlayer delamination or interface cracking during subsequent cycles. 180℃ is usually the appropriate temperature for crosslinking / densification of polysulfone resin and inorganic filler composite materials, and will not decompose the electrode material. The crosslinking degree of polysulfone is further improved at this temperature, which improves the thermal stability and high temperature resistance of the composite electrolyte. Too high a temperature can easily decompose the polymer or electrode active material; too low a temperature can hardly achieve sufficient flow and interface shaping. 180℃ is a relatively balanced and reliable choice in actual processes. Appropriate pressure is used to promote close contact between the electrolyte and the electrode, while excessive extrusion cannot cause electrode rupture or component extrusion. Pressure can effectively reduce interfacial voids and improve the integrity of ion transport channels. Under a suitable range of pressure, the battery stacking structure will not be excessively deformed or damaged.

[0048] The cooling control equation of the battery cell is: in, Indicates the battery cell at time The temperature in °C, Indicates the ambient temperature in °C. Indicates the constant that characterizes the heat transfer coefficient, k is 0.02~0.10 , represents the maximum cooling rate allowed, 5~10℃ / min, Indicates the cooling rate of the battery cell in °C / min.

[0049] If the temperature drops too quickly, the difference in thermal expansion coefficients of different materials will produce excessive internal stress, which can easily lead to cracking or peeling between layers. Limiting the temperature can effectively alleviate the stress accumulation caused by cooling. The battery layers obtained after controlled cooling are more firmly bonded, with fewer internal defects, and maintain low interfacial impedance and excellent mechanical strength in subsequent charge and discharge cycles.

[0050] Place one or more thermocouples / thermistors inside or on the surface of the battery cell sample and record the temperature over time, the ambient temperature You can use a room temperature meter or a thermostat with built-in sensors to measure. Heat the battery cell sample to a target temperature (e.g. 180°C) to ensure that the temperature distribution inside the entire battery is relatively uniform. After removing the heat source, allow the battery cell sample to cool at ambient temperature. Slowly cool down and record the temperature-time data during the cooling process , for example, record the temperature every 30 s or 1 min until the sample temperature approaches the ambient temperature. For the obtained temperature-time data substitute into to perform non-linear regression to obtain k. By restricting the cooling rate, stress concentration caused by differences in the coefficient of thermal expansion between materials is prevented, a high-quality, low-defect all-solid-state lithium-ion battery structure is achieved, and the battery life and safety are extended.

[0051] S3.2. Seal the battery core with an aluminum-plastic film or a metal casing to obtain an all-solid-state lithium-ion battery.

[0052] The present invention provides an all-solid-state lithium-ion battery, which is made by a preparation method of an all-solid-state lithium-ion battery. The all-solid-state lithium-ion battery includes a polysulfone-based composite electrolyte material, a positive electrode sheet, and a negative electrode sheet; wherein, is used to provide a lithium-ion transfer channel; The positive electrode sheet is used to exchange lithium ions with the negative electrode during charge and discharge; The negative electrode sheet is used to achieve reciprocating insertion and extraction of lithium ions between the positive electrode.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an all-solid-state lithium-ion battery, characterized in that the steps include: S1, dissolving a polysulfone resin in an organic solvent, adding an inorganic filler and heating to 150° C. to obtain a polysulfone-based composite electrolytic material; S2, mixing a sulfur source and a phosphorus source and heating them to form a sulfur-phosphorus complex, coating the sulfur-phosphorus complex on a positive electrode substrate, and heating to obtain a positive electrode sheet; S3, attaching the negative electrode sheet and the positive electrode sheet to the opposite sides of the polysulfone-based composite electrolytic material, heating to 180° C. and performing hot pressing to obtain the all-solid-state lithium-ion battery.

2. The method for preparing an all-solid-state lithium-ion battery according to claim 1, characterized in that: In step S1, the polysulfone resin includes at least one of polyphenylsulfone, polyethersulfone, and polychlorosulfonated benzene, the organic solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, and chloroform, and the inorganic filler includes at least one of lithium fluorophosphate, calcium titanate, and lithium fluoride.

3. The method for preparing an all-solid-state lithium-ion battery according to claim 1 or 2, characterized in that: Step S1 includes: S1.

1. Add polysulfone resin to organic solvent and stir using stirring equipment at room temperature. Continue stirring for 2 to 4 hours to ensure that the polysulfone resin is completely dissolved into a uniform solution. Until the polysulfone resin is completely dissolved; S1.2, adding an inorganic filler to the dissolved polysulfone resin, mixing using a high shear mixer at room temperature, the mixing process lasting 30 to 60 minutes, to obtain a composite solution; S1.3, placing the composite solution in an inert atmosphere, heating to 150°C and maintaining for 2 hours, and performing hot pressing after the heating is completed. The hot pressing stress is 2-5MPa, and the hot pressing time is 10-20 minutes. After cooling, a polysulfone-based composite electrolytic material is obtained.

4. The method for preparing an all-solid-state lithium-ion battery according to claim 1, characterized in that: In step S2, the sulfur source includes at least one of lithium sulfide and phosphorus pentasulfide, the phosphorus source includes at least one of aluminum dihydrogen phosphate and lithium phosphorus sulfide, and the positive electrode substrate includes at least one of aluminum foil, copper foil, and titanium alloy foil.

5. The method for preparing an all-solid-state lithium-ion battery according to claim 1 or 4, characterized in that: Step S2 includes: S2.1, ball-milling the sulfur source and the phosphorus source, and transferring them to a high-temperature reaction furnace, heating them to 200°C under nitrogen or argon protection, and maintaining them for 3 hours to obtain a sulfur-phosphorus complex; S2.

2. Mix the sulfur-phosphorus complex powder and the adjusting solvent to prepare an electrode slurry, use a coating machine to evenly coat it on the positive electrode substrate, then heat it to 300° C. and continue drying for 2 hours to obtain a positive electrode sheet, wherein the coating thickness of the electrode slurry is 50~100 μm.

6. The method for preparing an all-solid-state lithium-ion battery according to claim 5, characterized in that: Calculated according to the mass ratio, the sulfur source: the phosphorus source = (2~2.5):

1.

7. The method for preparing an all-solid-state lithium-ion battery according to claim 1, characterized in that: Step S3 includes: S3.1, stacking the polysulfone-based composite electrolytic material and the negative electrode sheet on the positive electrode sheet in sequence, transferring them to a flat mold of a hot press, slowly heating them to 180°C, applying a stress of 2-5 MPa while heating, maintaining for 10-30 minutes, slowly cooling them to room temperature after the hot pressing is completed, and gradually releasing the pressure to obtain a battery core; S3.

2. Use an aluminum-plastic film or a metal shell to seal the battery core to obtain the all-solid-state lithium-ion battery.

8. The method for preparing an all-solid-state lithium-ion battery according to claim 1 or 7, characterized in that: In step S3, the negative electrode sheet includes at least one of a lithium metal foil and a lithium titanate negative electrode sheet.

9. The method for preparing an all-solid-state lithium-ion battery according to claim 7, characterized in that: The cooling control equation of the battery core is: in, Indicates the battery cell at time The temperature in °C, Indicates the ambient temperature in °C. Indicates the constant that characterizes the heat transfer coefficient, k is 0.02~0.10 , represents the maximum cooling rate allowed, 5~10℃ / min, Indicates the cooling rate of the battery cell in °C / min.

10. An all-solid-state lithium-ion battery, characterized in that: The all-solid-state lithium-ion battery is prepared by the preparation method of any one of claims 1 to 9, wherein the all-solid-state lithium-ion battery comprises a polysulfone-based composite electrolytic material, a positive electrode sheet and a negative electrode sheet; wherein: The method is used to provide a lithium ion transfer channel; The positive electrode sheet is used to exchange lithium ions with the negative electrode during charging and discharging; The negative electrode sheet is used to realize the reciprocating embedding and de-embedding of lithium ions with the positive electrode.

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