Preparation method and application of a high-molecular polymer solid-state electrolyte

Abstract

The application belongs to the technical field of solid battery materials, and discloses a preparation method and application of a high-molecular polymer solid electrolyte. The preparation method comprises the following steps: (1) mixing sulfolane and polyacrylonitrile under a protective gas atmosphere, and heating and stirring to obtain a precursor solution; (2) adding propylene carbonate and trimethyl phosphate to the precursor solution, ultrasonic dispersion, then adding a lithium salt, and then centrifuging and defoaming to obtain a mixed solution; and (3) adding a crosslinking agent to the mixed solution, heating and keeping warm, and then drying to obtain the high-molecular polymer solid electrolyte. The high-molecular polymer solid electrolyte prepared by the preparation method has excellent mechanical properties and thermal stability, and meanwhile maintains high ionic conductivity, which is crucial for the performance of a solid-state battery.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery materials technology, and specifically relates to a method for preparing and applying a polymer solid electrolyte. Background Technology

[0002] Since Sony commercialized lithium-ion batteries in the early 1990s, these batteries have attracted widespread attention due to their significant advantages such as high energy density, long cycle life, and low self-discharge rate. These characteristics make lithium-ion batteries an ideal power source for portable electronic products and have driven the rapid development of related materials and technologies. With technological advancements and increasing societal demands, the application of lithium-ion batteries has expanded to more complex power systems such as pure electric and hybrid vehicles.

[0003] Lithium-ion batteries are the primary power source for modern electronic devices and electric vehicles, and their safety has always been a focal point of research and application. Liquid electrolyte batteries suffer from poor energy density and safety issues. Numerous fires and explosions caused by lithium-ion batteries have drawn significant public and industry attention. The main cause of these safety incidents lies in the easily leaking, volatile, and explosive organic electrolyte used inside the batteries, which is prone to thermal runaway under high pressure or high temperature operating conditions.

[0004] To address this challenge, solid-state battery technology has emerged, its core being the use of solid electrolytes to replace liquid electrolytes, thereby significantly improving battery safety and stability. In existing technologies, polymer solid-state electrolyte lithium-ion batteries are manufactured by tightly bonding polymer solid electrolytes between the positive and negative electrodes. While this design reduces the use of liquid electrolytes, it also introduces new technical challenges. The large presence of solid-solid interfaces leads to increased interfacial impedance, affecting the battery's charge / discharge rate and cycle performance.

[0005] With the growing global demand for clean energy and sustainable development, solid-state batteries, as the next generation of high-energy-density and high-safety energy storage devices, have attracted widespread attention from research institutions and industry. Compared to traditional liquid lithium-ion batteries, solid-state batteries theoretically offer higher safety and a longer lifespan because they use solid electrolytes instead of flammable liquid electrolytes. Furthermore, solid-state batteries are expected to offer higher energy density and a wider operating temperature range, making them ideal for electric vehicles, portable electronic devices, and applications requiring high energy and high power output.

[0006] However, the research and commercialization of solid-state batteries face a series of technical and engineering challenges. One of the most significant challenges is how to prepare solid-state electrolytes that possess both high ionic conductivity and good mechanical properties. Currently, the main material choices for solid-state electrolytes include inorganic ceramic materials, polymer materials, and composites of both. While inorganic ceramic materials exhibit excellent ionic conductivity, they typically suffer from insufficient mechanical flexibility and poor contact at the electrode interface. Polymer solid-state electrolytes, although flexible, generally have lower ionic conductivity, and their thermal and electrochemical stability needs improvement.

[0007] To overcome these limitations, researchers have been exploring novel solid-state electrolyte materials and preparation methods. For example, they have been improving ionic conductivity by introducing inorganic nanofillers into polymer matrices, or enhancing the thermal stability of polymers through chemical crosslinking.

[0008] Therefore, there is an urgent need to provide a new solid electrolyte with good thermal stability, conductivity and cycling stability. Summary of the Invention

[0009] This invention aims to provide a method for preparing and applying a polymer solid-state electrolyte. By combining the advantages of materials such as sulfolane and polyacrylonitrile, this invention develops a novel polymer solid-state electrolyte and an effective preparation method, hoping to overcome the limitations of current solid-state battery technology and promote its application in a wider range of fields. Through the efforts of this invention, a breakthrough in solid-state battery technology is expected, providing a safer, more efficient, and environmentally friendly solution for future energy storage and conversion. By employing innovative polymer materials and optimized preparation processes, high performance and high safety of solid-state batteries are achieved. The polymer solid-state battery of this invention not only eliminates the safety hazards of liquid electrolytes but also effectively reduces the interfacial impedance of the battery by precisely controlling the electrolyte synthesis and coating processes, making it extremely close to that of liquid electrolytes, thereby improving the battery's charge-discharge efficiency and cycle life. Furthermore, the heat treatment process of this invention further stabilizes the electrolyte structure, ensuring the reliability and stability of the battery under various operating conditions.

[0010] This invention relates to a solid electrolyte and its preparation method, particularly a solid electrolyte based on sulfolane and polyacrylonitrile polymers, and its application in solid-state batteries. The solid electrolyte of this invention, through careful design, achieves high ionic conductivity, excellent mechanical properties, and thermal stability, while ensuring battery safety, especially in preventing leakage, combustion, and explosion.

[0011] In this invention, sulfolane and polyacrylonitrile serve as precursors, forming the basic framework through specific synthetic steps. By introducing propylene carbonate and trimethyl phosphate as ion conductivity enhancers, not only is the ionic conductivity of the polymer solid electrolyte improved, but its flexibility and mechanical stability are also enhanced. Lithium perchlorate, as a lithium-ion conduction medium, further improves the ionic conductivity of the polymer solid electrolyte. Vinyl cyclobutene, as a crosslinking agent, is introduced through a specific heat treatment process, forming a stable three-dimensional network structure, which enhances the thermal stability and overall structural integrity of the polymer solid electrolyte.

[0012] The preparation method of this invention includes multiple steps such as precisely controlled chemical reaction, ultrasonic dispersion, high-speed centrifugation, vacuum degassing, and thermal curing, ensuring the uniformity, compactness, and consistency of the polymer solid electrolyte. Furthermore, by optimizing the coating process, precise thickness control of the polymer solid electrolyte is achieved, laying a solid foundation for the high performance and long lifespan of solid-state batteries.

[0013] The solid-state battery of this invention exhibits superior performance during assembly and testing. A series of detailed experimental examples, including physical performance testing, ionic conductivity measurement, thermal stability evaluation, and long-term cycle performance evaluation, comprehensively validated the performance of the polymer solid electrolyte and battery of this invention. Experimental results show that the solid-state battery of this invention outperforms existing technologies in terms of safety, conductivity, thermal stability, and cycle life.

[0014] In summary, this invention provides a method for preparing a polymer solid electrolyte with high safety, high conductivity, and high stability, providing important material and technical support for the development of solid-state batteries.

[0015] The first aspect of the present invention provides a method for preparing a polymer solid electrolyte.

[0016] Specifically, a method for preparing a polymer solid electrolyte includes the following steps: (1) Under a protective gas atmosphere, sulfolane and polyacrylonitrile were mixed, heated and stirred to obtain a precursor solution; (2) Add propylene carbonate and trimethyl phosphate to the precursor solution, disperse by ultrasonication, then add lithium salt, and then centrifuge and degas to obtain a mixture; (3) Add a crosslinking agent to the mixture, heat and keep warm, and then dry to obtain the polymer solid electrolyte.

[0017] Preferably, in step (1), the protective gas includes nitrogen or a rare gas (e.g., argon).

[0018] Preferably, in step (1), the heating and stirring temperature is 40~75℃, and the heating and stirring time is 3.5~7.5 hours. Under these conditions, the reaction between sulfolane and polyacrylonitrile is promoted to form a homogeneous precursor solution.

[0019] Preferably, in step (1), the molar ratio of sulfolane to polyacrylonitrile is 1:(0.5-1.5), and more preferably 1:1.

[0020] Preferably, in step (2), the mass ratio of propylene carbonate to trimethyl phosphate is 3:(0.5-1.5), and more preferably 3:1.

[0021] Preferably, in step (2), the mass of the propylene carbonate is 8 to 10% of the mass of the polyacrylonitrile.

[0022] Preferably, in step (2), the ultrasonic dispersion time is 10-30 minutes, and more preferably 20-30 minutes.

[0023] Preferably, in step (2), after the ultrasonic dispersion is completed, the mixture is stirred at 50-65°C for 1.5-2 hours.

[0024] Preferably, in step (2), the lithium salt includes lithium perchlorate.

[0025] Preferably, in step (2), the centrifugation speed is set to 8000-10000 rpm and the centrifugation time is 5-10 minutes.

[0026] Preferably, in step (2), the degassing treatment is carried out in a vacuum oven. The degassing treatment can remove bubbles generated by the chemical reaction, ensuring the uniformity and tightness of the electrolyte membrane.

[0027] Preferably, in step (3), the crosslinking agent includes cyclobutene.

[0028] Preferably, in step (3), the mass of the crosslinking agent is 0.5-1.5% of the mass of the polyacrylonitrile, and more preferably 0.8-1%.

[0029] Preferably, in step (3), the heating and heat preservation temperature is 110-120℃, and the time is 1.8-2 hours. Under these conditions, the shell promotes the crosslinking reaction between cyclobutadiene and polyacrylonitrile, forming a stable three-dimensional network structure.

[0030] Preferably, in step (3), the drying conditions are baking at 45~75°C for 24-48 hours under a vacuum of 0.1-0.2MPa to further remove the residual solvent in the polymer solid electrolyte.

[0031] A polymer solid electrolyte is prepared by the above-described method.

[0032] A solid-state battery includes a positive electrode, the aforementioned polymer solid electrolyte, and a negative electrode.

[0033] Preferably, the thickness of the polymer solid electrolyte is 15-35 micrometers, and more preferably 20-30 micrometers.

[0034] Preferably, the polymer solid electrolyte is disposed on the surface of the current collector.

[0035] The beneficial effects achieved by this invention are as follows: (1) The polymer solid electrolyte prepared by the preparation method of the present invention has excellent mechanical properties and thermal stability, while maintaining high ionic conductivity, which is crucial for the performance of solid-state batteries.

[0036] (2) In this invention, by introducing propylene carbonate and trimethyl phosphate as ion conduction enhancers, and lithium perchlorate as a lithium-ion conduction medium, the ion transport efficiency of the polymer solid electrolyte is significantly improved. In addition, the crosslinking effect of cyclobutene further enhances the structural stability of the electrolyte, enabling it to withstand stress and temperature changes during battery operation.

[0037] (3) The preparation method of the present invention includes a series of innovative steps, such as the synthesis of precursor solution, the optimized ratio of each component, the doping of lithium salt, the introduction of crosslinking agent, and the precise control of the curing process. These steps together ensure the uniformity and compactness of the polymer solid electrolyte, providing a solid foundation for the high performance and long life of solid-state batteries.

[0038] (4) The solid-state battery of the present invention exhibits excellent performance in terms of safety, conductivity, thermal stability, and cycle life. In particular, in safety tests, the solid-state battery of the present invention remains stable even under extreme conditions, demonstrating higher safety assurance than traditional liquid electrolyte batteries. Furthermore, through long-term cycling and accelerated aging tests, the solid-state battery of the present invention demonstrates reliability and durability in practical applications.

[0039] In summary, this invention not only provides a high-performance solid electrolyte material for the field of solid-state batteries but also a feasible preparation method, which helps to promote the commercialization of solid-state battery technology. The polymer solid electrolyte and solid-state battery of this invention are expected to be widely used in portable electronic devices, electric vehicles, large-scale energy storage systems, and other fields, providing safer, more efficient, and more environmentally friendly energy solutions for modern society. In the future, the technology of this invention can be further optimized and developed to meet the growing demand for energy storage and contribute to the development of sustainable energy globally. Detailed Implementation

[0040] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0041] Example 1: Preparation of Polymer Solid Electrolytes A method for preparing a polymer solid electrolyte includes the following steps: (1) Under a protective gas (dry nitrogen) atmosphere, sulfolane and polyacrylonitrile were mixed in a round-bottom flask at a molar ratio of 1:1. The mixture was stirred with a magnetic stirrer at room temperature for 6 hours. The round-bottom flask was placed in an oil bath and slowly heated to 60°C and maintained at this temperature for 6 hours. During this period, the mixture was continuously stirred to promote the chemical reaction between sulfolane and polyacrylonitrile to form a homogeneous precursor solution. (2) Add propylene carbonate and trimethyl phosphate (mass ratio of propylene carbonate to trimethyl phosphate is 3:1, and the mass of propylene carbonate is 8% of the mass of polyacrylonitrile) to the precursor solution, sonicate the mixture for 30 minutes using an ultrasonic disperser, stir at 60°C for 2 hours, then add lithium perchlorate, the mass of lithium perchlorate is 5% of the mass of polyacrylonitrile, then centrifuge (centrifugation speed set to 10000 rpm, duration 10 minutes) and degas in a vacuum oven to obtain a mixture; (3) Add cyclobutene to the mixture, the mass of which is 1% of the polyacrylonitrile, heat to 120°C and keep for 2 hours, then place in a vacuum oven and bake at 60°C for 48 hours under a vacuum of 0.1 MPa to obtain a polymer solid electrolyte.

[0042] Comparative Example 1 Compared with Example 1, the only difference in Comparative Example 1 is that dimethyl sulfoxide (DMSO) is used instead of sulfolane in Example 1, and the other processes are the same as in Example 1.

[0043] Comparative Example 2 Compared with Example 1, the only difference in Comparative Example 2 is that ethylene carbonate (EC) is used instead of propylene carbonate in Example 1, and the other processes are the same as in Example 1.

[0044] Comparative Example 3 Compared with Example 1, the only difference in Comparative Example 3 is that dimethyl phosphate (DMP) is used instead of trimethyl phosphate in Example 1, while the other processes are the same as in Example 1.

[0045] Solid-state battery assembly and performance evaluation: The prepared solid electrolyte membrane (the preparation method for solid electrolyte membranes of different thicknesses is a conventional process, such as using a precision coating machine to uniformly coat the solid electrolyte onto the battery current collector to form a solid electrolyte membrane of corresponding thickness) is assembled with positive electrode materials (e.g., lithium iron phosphate, lithium-rich materials) and negative electrode materials (e.g., graphite, silicon carbide, lithium metal, etc.) optimized using the same method to form a coin cell. Laser welding technology is used to precisely weld the battery components, ensuring the battery's sealing and long-term stability.

[0046] A series of performance tests are conducted on the assembled solid-state battery, including but not limited to cyclic voltammetry, AC impedance, thermal stability and safety tests, to comprehensively evaluate the battery's performance and reliability.

[0047] Through the aforementioned complex preparation process, the solid electrolyte of this invention exhibits excellent ionic conductivity, mechanical stability, and thermal stability, providing a solid material foundation for the commercial application of solid-state batteries.

[0048] Post-processing and characterization of solid electrolyte membranes: Surface treatment is performed on the solid electrolyte membrane, and the membrane surface is modified at low temperature (e.g., 10°C) using plasma treatment equipment to increase its hydrophilicity and hydrophobicity, thereby improving its contact performance with electrode materials.

[0049] The surface roughness of the electrolyte membrane was characterized using atomic force microscopy (AFM) to ensure that its surface flatness met the requirements for battery assembly.

[0050] The crystal structure of the solid electrolyte membrane was analyzed by X-ray diffraction (XRD) to confirm its phase purity and crystal structure stability.

[0051] Environmental adaptability testing: Solid-state batteries were tested under different environmental conditions, including high and low temperature tests, humidity tests, and vibration tests, to evaluate their performance and stability in extreme environments.

[0052] These tests determine the operating temperature range and humidity requirements of the battery, providing guidance for its practical application.

[0053] Physical property testing of solid electrolyte membranes: Five solid electrolyte membranes of different thicknesses were prepared, with thicknesses of 20 μm, 25 μm, 30 μm, 35 μm, and 40 μm, respectively. (The preparation methods for the solid electrolyte membranes of different thicknesses were conventional processes, such as using a precision coating machine to uniformly coat the solid electrolyte onto the battery current collector to form a solid electrolyte membrane of the corresponding thickness.) The thickness of each membrane was accurately measured using an electronic thickness gauge, and the data were recorded.

[0054] Tensile tests were performed on each electrolyte membrane using a universal testing machine. Different tensile speeds (such as 1 mm / min, 5 mm / min, and 10 mm / min) were set, and the stress-strain curves at each speed were recorded. The tensile strength and elongation at break of membranes with different thicknesses were calculated.

[0055] The surface morphology and cross-sectional structure of the electrolyte membrane before and after stretching were observed by scanning electron microscopy (SEM) to evaluate the effects of crosslinking density and uniformity on membrane performance.

[0056] Measurement of ionic conductivity and activation energy: Impedance spectroscopy of the solid-state battery was performed using an AC impedance analyzer in the frequency range of 20 Hz to 100 kHz, and the changes in impedance amplitude and phase angle were recorded. The ionic conductivity of the electrolyte was calculated by fitting the impedance spectrum data.

[0057] Repeated impedance tests were conducted at different temperatures (e.g., -30℃, -20℃, 0℃, 25℃, 40℃, 60℃, and 80℃), and the activation energy of ionic conductivity of the electrolyte was calculated using the Arrhenius equation to evaluate the effect of temperature on conductivity.

[0058] Studies on thermal stability and thermal decomposition behavior: Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed on the solid electrolyte membrane. The TGA test was conducted in a nitrogen atmosphere, with a temperature range from room temperature to 500 °C and a heating rate set at 10 °C / min. Mass changes were recorded and thermal decomposition products were analyzed.

[0059] DSC testing is used to determine the glass transition temperature (Tg) and thermal stability of the electrolyte. DSC tests are performed in a nitrogen atmosphere at a heating rate of 5 °C / min, and heat flow changes are recorded to assess the electrolyte's thermal stability and thermal decomposition temperature.

[0060] Solid-state battery assembly and long-term cycle performance evaluation: Solid-state batteries were subjected to cycle performance tests at different charge / discharge rates from 0.5C to 2C. The initial capacity, energy density, and cycle life were recorded at each rate to evaluate the battery's rate performance and long-term stability.

[0061] Long-term cycle testing was conducted using a charge / discharge rate of 0.5C. A detailed performance evaluation was performed after every 100 cycles, including capacity retention, energy density change, and internal resistance increase. These data were used to evaluate the battery's cycle stability and aging behavior.

[0062] Electrochemical stability test: Electrochemical stability tests were performed on the solid electrolyte membrane using an electrochemical workstation. The electrolyte membrane was clamped between two stainless steel electrodes to assemble an electrochemical test cell.

[0063] Cyclic voltammetry (CV) tests were performed on an electrochemical workstation with a scan potential range of 4.0 V to 67.0 V and a scan rate of 0.1 mV / s to evaluate the electrochemical window and stability of the electrolyte.

[0064] Record the current-voltage curves during the test and analyze the oxidation and reduction stability of the electrolyte to ensure its suitability for high-voltage solid-state battery systems.

[0065] Interfacial impedance analysis: For the assembled solid-state battery, interfacial impedance was tested using an AC impedance analyzer within the frequency range of 0.1 Hz to 100 kHz. The impedance spectrum of the battery was recorded and fitted using an equivalent circuit model to evaluate the interfacial impedance between the electrolyte and the electrodes.

[0066] By comparing the battery interface impedance under different electrolyte membrane thicknesses and preparation conditions, the optimal electrolyte membrane thickness and preparation parameters are determined to achieve the best battery performance.

[0067] Solid-state battery rate performance test: Solid-state batteries were charged and discharged at different rates (e.g., 0.2C, 0.5C, 1C, 2C, and 5C), and the discharge capacity and energy density at each rate were recorded.

[0068] The rate performance of the battery was analyzed to determine the effect of the electrolyte membrane's ion conduction performance on the battery's charge and discharge rate, as well as the battery's performance retention under high-rate operating conditions.

[0069] Long-term cycle life testing of solid-state batteries: Choose a suitable charge / discharge rate (e.g., 1C) and conduct long-term cycle tests on the solid-state battery, cycling for 1000 cycles.

[0070] Long-term cycling tests were conducted to evaluate the durability and reliability of solid-state batteries, as well as the chemical and physical stability of the electrolyte membrane during long-term use.

[0071] Accelerated aging test of solid-state batteries: The solid-state battery was placed in a high-temperature environment (e.g., 60°C) for accelerated aging testing. Under high-temperature conditions, a cyclic test was performed at a charge-discharge rate of 1C, and the battery performance parameters were recorded after every 100 cycles.

[0072] The study analyzes the performance degradation of batteries under high-temperature conditions and evaluates the thermal stability of solid electrolyte membranes and the overall thermal management requirements of batteries.

[0073] Through these detailed experimental examples, the performance of the solid electrolyte and battery of the present invention has been comprehensively evaluated and verified, providing solid data support for further optimization and application.

[0074] Example 1: Performance test results of solid electrolyte: The absence of large crystalline structures in solid electrolyte membranes indicates that the material possesses amorphous properties, which helps to improve ion conductivity.

[0075] Thermogravimetric analysis: The solid electrolyte membrane only begins to decompose when heated to 500°C in air, exhibiting good thermal stability.

[0076] Differential scanning calorimetry: Solid electrolyte membranes do not have obvious thermal peaks in the range of -50℃ to 80℃, and have good electrochemical stability.

[0077] Mechanical property testing: Tensile strength test showed that the tensile strength of the solid electrolyte membrane was 10 MPa and the elongation at break was 5%, indicating that it has good mechanical strength and flexibility.

[0078] Cyclic voltammetry test: The solid electrolyte membrane did not undergo oxidative decomposition at a high voltage of 4.5V, indicating that it has a high electrochemical window.

[0079] Electron impedance spectroscopy: The ionic impedance of the solid electrolyte membrane measured by EIS is 100 Ω·cm. 2 Its electronic impedance is negligible, indicating that it has excellent ion conduction properties.

[0080] Long-term cycling test: After 1000 charge-discharge cycles, the conductivity of the solid electrolyte membrane decreased by only 5%, indicating that it has excellent cycling stability.

[0081] The test results of Comparative Example 1 under the same conditions are as follows: Ionic conductivity: from 1×10 -3 S / cm decreased to 5×10 -4 S / cm; Interface resistance: from 100 Ω·cm 2 Increased to 500 Ω·cm 2 ; After replacement, the ionic conductivity of the electrolyte membrane decreased and the interfacial resistance increased. This may be due to the high viscosity of DMSO, which leads to a decrease in ion transport efficiency.

[0082] The test results of Comparative Example 2 under the same conditions are as follows: Electrochemical window: decreased from 4.5V to 4.0V; Cyclic stability: The conductivity decreased by 10% after 1000 cycles, while that of the present invention decreased by only 5%; EC has a narrower electrochemical window compared to propylene carbonate, which may lead to reduced battery stability at high voltages and a decrease in cycle stability.

[0083] The test results of Comparative Example 3 under the same conditions are as follows: Open-circuit voltage (OCV) stability: After long-term storage, the OCV decreased by 0.1V; Thermal stability: During the 60℃ high-temperature test, the electrolyte membrane exhibited localized decomposition; DMP may have lower thermal and chemical stability than trimethyl phosphate, leading to decreased battery performance at high temperatures and affecting OCV stability.

[0084] According to experimental data, if sulfolane, propylene carbonate and trimethyl phosphate in this invention are replaced with other substances of the same type, the electrical performance of the solid electrolyte membrane may decrease to varying degrees.

[0085] The solid-state electrolyte preparation method of this invention includes a series of innovative steps, such as the synthesis of precursor solutions of sulfolane and polyacrylonitrile, the optimized ratio of ion conduction enhancers, the doping of lithium perchlorate, the crosslinking of cyclobutene, and a precisely controlled curing process. These steps together ensure the uniformity and compactness of the solid-state electrolyte membrane, providing a solid foundation for the high performance and long lifespan of solid-state batteries.

[0086] Experimental results show that the solid-state battery of this invention exhibits excellent performance in terms of physical properties, ionic conductivity, thermal stability, and cycle life. Particularly in safety tests, the solid-state battery of this invention remains stable even under extreme conditions, demonstrating higher safety assurance than traditional liquid electrolyte batteries. Furthermore, long-term cycling and accelerated aging tests have proven the reliability and durability of the solid-state battery in practical applications.

[0087] In summary, this invention not only provides a high-performance solid electrolyte material for the field of solid-state batteries but also a feasible preparation method, which helps to promote the commercialization of solid-state battery technology. The solid electrolyte and battery of this invention are expected to be widely used in portable electronic devices, electric vehicles, large-scale energy storage systems, and other fields, providing safer, more efficient, and more environmentally friendly energy solutions for modern society. In the future, the technology of this invention can be further optimized and developed to meet the growing demand for energy storage and contribute to the development of sustainable energy globally.

[0088] This invention provides a method for preparing a solid-state battery based on polymer materials, aiming to address the safety hazards associated with liquid electrolytes in traditional lithium-ion batteries, such as leakage, combustion, and explosion. By using polymers as the solid-state electrolyte, the battery of this invention exhibits superior safety and environmental friendliness, effectively avoiding the risk of leakage of harmful chemicals in traditional batteries.

[0089] The solid-state battery of this invention is not only structurally more robust, but also exhibits higher thermal stability under extreme conditions, completely eliminating the risk of explosion and combustion. Furthermore, the preparation method of this invention is simple and efficient, facilitating large-scale production and application, while ensuring high battery performance and long lifespan.

[0090] By precisely controlling the synthesis conditions and coating process of the polymer electrolyte, this invention ensures the uniformity and compactness of the electrolyte layer, reducing the resistance caused by the solid-solid interface, thereby improving the overall performance and safety of the battery. The novel heat treatment process further stabilizes the electrolyte structure, improves ion conductivity, and ensures good compatibility and long-term stability between battery components.

[0091] Through a series of experiments and tests, the solid-state electrolyte and its preparation method proposed in this invention have been proven to possess several significant technical advantages and practical application potential. Through a carefully designed chemical composition and meticulous preparation process, this invention successfully prepared a solid-state electrolyte with high ionic conductivity, excellent mechanical properties, and outstanding thermal stability. These characteristics enable the solid-state electrolyte of this invention to exhibit superior safety in solid-state batteries, particularly in preventing safety risks such as battery leakage, combustion, and explosion.

[0092] The above description outlines the basic principles, main features, and advantages of this invention. Those skilled in the art should understand that the scope of protection of this invention is not limited to the above embodiments. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A method for producing a high-molecular polymer solid electrolyte, characterized by comprising the steps of: Includes the following steps: ​ (1) Under a protective gas atmosphere, sulfolane and polyacrylonitrile were mixed, heated and stirred to obtain a precursor solution; (2) Add propylene carbonate and trimethyl phosphate to the precursor solution, disperse by ultrasonication, then add lithium salt, and then centrifuge and degas to obtain a mixture; (3) Add a crosslinking agent to the mixture, heat and keep warm, and then dry to obtain the polymer solid electrolyte.

2. The production method according to claim 1, characterized by, In step (1), the protective gas includes nitrogen or a rare gas.

3. The production method according to claim 1, characterized by, In step (1), the heating and stirring temperature is 40~75℃ and the heating and stirring time is 3.5~7.5 hours.

4. The method of claim 1, wherein, In step (1), the molar ratio of sulfolane to polyacrylonitrile is 1:(0.5-1.5).

5. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of propylene carbonate to trimethyl phosphate is 3:(0.5-1.5).

6. The preparation method according to claim 1, characterized in that, In step (2), the mass of the propylene carbonate is 8 to 10% of the mass of the polyacrylonitrile.

7. The preparation method according to claim 1, characterized in that, In step (2), the lithium salt includes lithium perchlorate.

8. The preparation method according to any one of claims 1-7, characterized in that, In step (2), the centrifugation speed is set to 8000-10000 rpm, and the centrifugation time is 5-10 minutes; And / or, in step (2), the degassing treatment is carried out in a vacuum oven; And / or, in step (3), the crosslinking agent includes cyclobutene; And / or, in step (3), the mass of the crosslinking agent is 0.5-1.5% of the mass of the polyacrylonitrile; And / or, in step (3), the heating and heat preservation temperature is 110-120℃ and the time is 1.8-2 hours.

9. A polymer solid electrolyte, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. A solid-state battery, characterized in that, It includes a positive electrode, a polymer solid electrolyte as described in claim 9, and a negative electrode.