All-solid oxide-polymer electrolyte membrane and preparation method and application thereof

Abstract

The invention belongs to the technical field of development and manufacturing of solid-state electrolyte materials and solid-state lithium batteries, and particularly relates to an all-solid-state oxide-polymer electrolyte membrane as well as a preparation method and application thereof. The electrolyte membrane comprises a polymer matrix, a lithium salt, butanedinitrile, lithium lanthanum zirconium tantalum oxide and graphite phase carbon nitride, the polymer matrix, the lithium salt, the butanedinitrile, the lithium lanthanum zirconium tantalum oxide and the graphite phase carbon nitride are uniformly mixed to form a solid film; the polymer matrix is polyacrylonitrile and forms a framework of the electrolyte membrane; the lithium salt, the butanedinitrile, the lithium lanthanum zirconium tantalum oxide and the graphite phase carbon nitride are at least physically and uniformly dispersed in the polymer matrix. The electrolyte membrane can be prepared through the steps of slurry preparation, defoaming treatment, membrane forming processing, drying and curing and the like, and can be used in a solid-state lithium battery, so that the contact between the electrolyte membrane and an electrode interface is improved, side reaction is inhibited, the ion transmission efficiency and mechanical property are improved, the interface impedance is reduced, and the cycling stability and safety of the solid-state lithium battery are enhanced.

Description

Technical Field

[0001] This invention belongs to the field of development and manufacturing technology of solid electrolyte materials and solid lithium batteries, specifically relating to an all-solid oxide-polymer electrolyte membrane, its preparation method and application. Background Technology

[0002] With the rapid development of consumer electronics, new energy vehicles, and large-scale energy storage, the market has placed increasingly stringent demands on the safety, energy density, and long-term cycle stability of lithium batteries. Currently, commercially available lithium batteries generally use a liquid electrolyte system. Although this system has high room-temperature ionic conductivity, it has significant drawbacks: liquid electrolytes are prone to leakage, combustion, and even explosion due to overcharging, short circuits, or high-temperature environments, posing significant safety hazards. Furthermore, liquid electrolytes have poor compatibility with lithium metal anodes, easily inducing lithium dendrite growth and triggering side reactions. This not only limits the application of lithium metal anodes but also leads to shortened battery cycle life and rapid capacity decay, making it difficult to meet the technical requirements of next-generation high-performance energy storage devices.

[0003] Replacing liquid electrolytes with solid-state electrolytes is a key approach to improving the safety and energy density of lithium-ion batteries. Solid-state batteries fundamentally avoid the leakage and combustion risks associated with liquid electrolytes, while also being compatible with lithium metal anodes and high-voltage cathodes, making it possible to design power systems with higher energy density. Among various polymer electrolytes, polyacrylonitrile (PAN)-based electrolyte membranes have received widespread attention due to their wide electrochemical window (>4.5V) and good oxidation resistance, making them particularly suitable for next-generation high-voltage solid-state battery systems.

[0004] However, PAN-based electrolytes have two significant drawbacks. Firstly, the highly polar cyano groups (C≡N) in their molecular chains impede chain movement, resulting in high rigidity and poor flexibility. After drying, they struggle to form a tight interfacial contact with the electrode, leading to high interfacial impedance and ion transport barriers. Secondly, PAN is thermodynamically unstable with lithium metal, and the C≡N groups readily undergo side reactions with lithium, generating a highly impedance and unstable passivation interfacial layer (SEI). This SEI has a porous structure and low ionic conductivity, continuously thickening during cycling, leading to the continuous depletion of active lithium, deterioration of interfacial kinetics, a decrease in battery coulombic efficiency, and rapid capacity decay. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an all-solid-state oxide-polymer electrolyte membrane, its preparation method, and its applications.

[0006] This invention introduces succinic anionyl nitrile (SN) plastic crystals and graphitic carbon nitride (g) into a polyacrylonitrile (PAN) matrix. -C3N4) and solid electrolyte LLZTO synergistically optimize the mechanical properties and interfacial chemistry of the electrolyte membrane. The addition of SN significantly enhances the flexibility and film-forming properties of the electrolyte membrane; its plastic crystal characteristics help promote ion transport and improve interfacial contact with the electrode, effectively alleviating solid-solid interface impedance problems. The added g... - C3N4 can be preferentially reduced on the lithium metal surface, forming a dense and stable SEI layer rich in Li3N in situ. This interface possesses high lithium-ion conductivity and mechanical strength, significantly suppressing side reactions between PAN and lithium, and improving interfacial compatibility and battery cycle stability. Simultaneously, the addition of the solid electrolyte LLZTO provides the solid electrolyte membrane with more ion transport channels and enhances its mechanical properties.

[0007] A first aspect of the present invention is to provide an all-solid-state oxide-polymer electrolyte membrane comprising a polymer matrix, a lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride; wherein the polymer matrix, lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride are uniformly mixed to form a solid film; wherein the polymer matrix is ​​polyacrylonitrile, constituting the framework of the electrolyte membrane; wherein the lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride are at least physically uniformly dispersed in the polymer matrix.

[0008] As a further optimization of the all-solid-state oxide-polymer electrolyte membrane, the lithium salt used is lithium perchlorate (LiClO4).

[0009] As a further optimization scheme for the all-solid oxide-polymer electrolyte membrane, the mass ratio of polymer matrix, lithium salt, succinate, lithium lanthanum zirconium tantalum oxide and graphitic carbon nitride is (3~5): (1~3): (1~2): (2~5): (0.01~0.06).

[0010] As a further optimization of the all-solid-state oxide-polymer electrolyte membrane, the mass ratio of polymer matrix, lithium salt, succinic acid, lithium lanthanum zirconium tantalum oxide and graphitic carbon nitride is 4: 2: 1: 3: 0.03.

[0011] The second aspect of the present invention is to provide a method for preparing an all-solid oxide-polymer electrolyte membrane, wherein a polymer matrix, lithium salt, succinate, lithium lanthanum zirconium tantalum oxide and graphitic carbon nitride are mixed in an organic solvent to form a uniform slurry, and then the slurry is formed and dried to obtain an all-solid oxide-polymer electrolyte membrane.

[0012] Furthermore, the all-solid-state oxide-polymer electrolyte membrane is any of the above-mentioned electrolyte membranes, and its preparation method includes the following steps: (1) Slurry preparation: The polymer matrix, lithium salt, succinate, lithium lanthanum zirconium tantalum oxide and graphitic carbon nitride are dispersed together in an organic solvent and the components are thoroughly mixed by mechanical stirring to form a stable and uniform slurry system. (2) Degassing treatment: The slurry obtained in step (1) is allowed to stand or centrifuged or depressurized to remove the air bubbles entrained therein, so as to obtain a dense slurry; (3) Film forming process: The degassed slurry is cast or coated onto a clean substrate to form a wet film of uniform thickness; (4) Drying and curing: The wet film obtained in step (3) is dried under heating and / or negative pressure conditions to remove organic solvents and form a dense solid electrolyte membrane with self-supporting properties, thus obtaining the all-solid oxide-polymer electrolyte membrane.

[0013] As a further optimization of the preparation method, the organic solvent in step (1) is N,N-dimethylformamide (DMF).

[0014] A third aspect of the present invention is to provide an application scheme for the above-mentioned all-solid-state oxide-polymer electrolyte membrane in the preparation of solid-state lithium batteries.

[0015] As a preferred embodiment, the solid-state lithium battery is an all-solid-state battery with lithium metal as the negative electrode, and its structure includes, in sequence, a positive electrode, the all-solid-state oxide-polymer electrolyte membrane, and a lithium metal negative electrode.

[0016] As an alternative preferred embodiment, the solid-state lithium battery is a flexible pouch battery, the structure of which includes a cell composed of a positive electrode sheet, the all-solid-state oxide-polymer electrolyte membrane and a lithium metal negative electrode stack, and a flexible packaging shell for encapsulating the cell.

[0017] Beneficial effects To improve the problems of poor interfacial contact and poor compatibility between PAN polymer electrolyte and electrode, this invention introduces SN and g - The composition of C3N4 and solid-state electrolyte LLZTO was optimized. The plasticizing effect of SN effectively improved the ionic conductivity of the electrolyte and promoted the formation of a tight interface with the electrode, thereby ensuring the efficient transport of lithium ions inside the battery. - The addition of C3N4 promotes the in-situ formation of a Li3N-rich ion-conducting SEI layer. This layer isolates the electrolyte from direct contact with lithium metal, suppresses side reactions of C≡N groups on lithium, and thus enhances interfacial compatibility. The addition of the solid electrolyte LLZTO provides more ion transport channels for the solid electrolyte membrane and enhances its mechanical properties. The results show that by controlling the composition of the PAN-based electrolyte, its interfacial stability with the electrode can be significantly improved, promoting the application of this type of polymer electrolyte in high-performance solid-state lithium batteries. Attached Figure Description

[0018] Figure 1 Electrochemical impedance spectroscopy (EIS) spectra and magnified views of lithium-symmetric batteries assembled from PAN, PAN-SN, and PAN-SNL solid electrolyte membranes, respectively, are shown. (a) is the full EIS spectrum, and (b) is a magnified view of the lower left region of (a). Figure 2 The cycling performance of Li / PAN-SNL / Li batteries at 30℃ and 0.1 mA·cm⁻² is shown in the comparison of electrochemical impedance spectroscopy (EIS) before and after cycling. Among them, (a) is the voltage-time cycling curve, and (b) is the comparison of EIS after the 1st cycle and the 700th cycle. Figure 3 The graphs show the electrochemical performance of an NCM / PAN-SNL / Li battery with a positive electrode loading of approximately 6.2 mg·cm⁻² at 30 °C and a cutoff voltage of 4.2 V. In the graphs, (a) is the charge-discharge curve at 0.5 C and (b) is the curve of the specific capacity and coulombic efficiency as a function of the number of cycles. Figure 4 The images show actual photos of NCM / PAN-SNL / Li pouch batteries with LEDs lit up in different states. (a) shows the LEDs lit up in a flat state, (b) shows the LEDs lit up in a bent state, and (c) shows the LEDs lit up in an open environment after being partially cut. Detailed Implementation

[0019] The present invention is further illustrated below with specific embodiments. These embodiments are exemplary and intended to illustrate the problem and explain the present invention, and are not intended to be limiting.

[0020] The raw materials used in the following embodiments of the present invention are as follows: polyacrylonitrile (PAN) is from Macklin, with a molecular weight of 200,000; succinic anionyl nitrile (SN) is from Aladdin; lithium perchlorate (LiClO4) is from Sinopharm Reagent and Sigma-Aldrich; lithium lanthanum zirconium tantalum oxide (LLZTO) is from Shanghai Keyuan Solid Energy New Energy Technology Co., Ltd.; graphitic carbon nitride (g-C3N4) is from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; N-methylpyrrolidone (NMP) is from Sinopharm Reagent; polyvinylidene fluoride (PVDF) is from Solvay, model 5130; acetylene black is from Yiruishi, model SP; ternary cathode material (NCM811, i.e., KELOD Nickel Cobalt Manganese 811 cathode); lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is from Aladdin. Unless otherwise specified, the materials, methods, and equipment used in the embodiments of the present invention are conventional materials, methods, and equipment in this technical field.

[0021] Example 1 The composite modified solid electrolyte membrane is mainly prepared by solution casting. The specific steps are as follows: First, polyacrylonitrile (PAN), succinic anionylene (SN), lithium perchlorate (LiClO4), and solid electrolyte LLZTO are accurately weighed according to the mass ratio m(PAN):m(SN):m(LiClO4):m(LLZTO) = 4:1:2:3, and dissolved together in N,N-dimethylformamide (DMF) solvent. Then, an additional 3% of the total mass of polyacrylonitrile (PAN), succinic anionylene (SN), lithium perchlorate (LiClO4), and solid electrolyte LLZTO is added. - C3N4 was used as an interface stabilizer. The mixed solution was then placed in an oil bath at 80°C and continuously mechanically stirred for 10 hours to ensure complete dissolution and reaction, ultimately obtaining a uniform, transparent, viscous slurry. Afterward, the slurry was allowed to stand for a period to remove internal air bubbles, and then uniformly coated onto a clean glass substrate using a precision coater to form a wet film. Next, the sample was transferred to a vacuum drying oven at 80°C and dried for 12 hours to completely remove the DMF solvent, forming a dense and self-supporting PAN-SNL composite modified solid polymer electrolyte membrane. Finally, the prepared electrolyte membrane was cut into 19mm diameter discs using a cutting machine and stored in a dry environment for subsequent battery assembly and electrochemical testing.

[0022] Preparation of the positive electrode: NCM, acetylene black, LiTFSI, PVDF, and SN were weighed in a mass ratio of 80:10:10:10:5 and dispersed together in N-methylpyrrolidone (NMP) solvent. The mixture was magnetically stirred for 12 hours to ensure thorough dispersion and uniform mixing, followed by standing for 2 hours to remove air bubbles. Then, it was uniformly coated onto the surface of an aluminum foil current collector using a doctor blade coating process. The coated electrode was then dried in an 80°C vacuum oven for 24 hours to completely remove the solvent. Finally, the dried electrode was cut into 8mm diameter discs, yielding a positive electrode active material areal loading of approximately 2.4 mg•cm⁻², for subsequent battery assembly.

[0023] Assembly of button cells: All cells use 2032 button cell cases and are assembled in an argon atmosphere glove box. The oxygen and moisture content in the operating environment is below 0.1 ppm.

[0024] AC impedance test battery: The structure consists of a 0.5mm thick stainless steel sheet (positive electrode side), a solid electrolyte membrane, a 1mm thick stainless steel sheet, and a stainless steel spring sheet (negative electrode side). Lithium symmetric battery cycle test: Two 0.5mm thick lithium sheets are used to contact the two sides of the solid electrolyte membrane respectively, and the outer side is supplemented with a 0.5mm stainless steel sheet and a spring sheet to complete the encapsulation; Full cell cycle test: The positive electrode, solid electrolyte membrane, 0.5mm thick lithium sheet, and 0.5mm thick stainless steel sheet and spring are stacked in sequence.

[0025] All assembled batteries were left to stand at 60°C for 6 hours to promote full contact at the electrode / electrolyte interface, after which electrochemical tests were performed.

[0026] Pouch Battery Assembly: Cut the positive electrode sheet into a 6cm × 5cm rectangle, and cut the solid electrolyte membrane and lithium foil into 6.5cm × 4.5cm dimensions respectively. Prepare copper foil current collectors of the same size. Solder the aluminum tabs to the LFP electrode sheet and the nickel tabs to the copper foil. Align the battery stack in the following order: positive electrode sheet—electrolyte membrane—lithium foil—copper foil, with all tabs on the same side. Pack the stacked cells into an aluminum-plastic film packaging bag and seal it multiple times using a heat sealer to ensure an internal vacuum environment.

[0027] Comparative Example 1 Solid electrolyte membranes were prepared by solution casting, with the following specific steps: First, a measured amount of polyacrylonitrile (PAN) was dissolved in N,N-dimethylformamide (DMF) solvent. Then, an additional 3% (by mass) of g of [a specific chemical compound] was added to the solution. - C3N4 was used as an interface stabilizer. The mixed solution was then placed in an oil bath at 80°C and continuously mechanically stirred for 10 hours to ensure complete dissolution and reaction, ultimately obtaining a uniform, transparent, viscous slurry. Afterward, the slurry was allowed to stand for a period to remove internal air bubbles, and then uniformly coated onto a clean glass substrate using a precision coater to form a wet film. Next, the sample was transferred to a vacuum drying oven at 80°C and dried for 12 hours to completely remove the DMF solvent, forming a dense and self-supporting PAN-N composite modified solid polymer electrolyte membrane. Finally, the prepared electrolyte membrane was cut into 19mm diameter discs using a cutting machine and stored in a dry environment for subsequent battery assembly and electrochemical testing.

[0028] Preparation of the positive electrode: NCM, acetylene black, LiTFSI, PVDF, and SN were weighed in a mass ratio of 80:10:10:10:5 and dispersed together in N-methylpyrrolidone (NMP) solvent. The mixture was magnetically stirred for 12 hours to ensure thorough dispersion and uniform mixing, followed by standing for 2 hours to remove air bubbles. Then, it was uniformly coated onto the surface of an aluminum foil current collector using a doctor blade coating process. The coated electrode was then dried in an 80°C vacuum oven for 24 hours to completely remove the solvent. Finally, the dried electrode was cut into 8mm diameter discs, yielding a positive electrode active material areal loading of approximately 2.4 mg•cm⁻², for subsequent battery assembly.

[0029] Assembly of button cells: All cells use 2032 button cell cases and are assembled in an argon atmosphere glove box. The oxygen and moisture content in the operating environment is below 0.1 ppm.

[0030] AC impedance test battery: The structure consists of a 0.5mm thick stainless steel sheet (positive electrode side), a solid electrolyte membrane, a 1mm thick stainless steel sheet, and a stainless steel spring sheet (negative electrode side). Lithium symmetric battery cycle test: Two 0.5mm thick lithium sheets are used to contact the two sides of the solid electrolyte membrane respectively, and the outer side is supplemented with a 0.5mm stainless steel sheet and a spring sheet to complete the encapsulation; Full cell cycle test: The positive electrode, solid electrolyte membrane, 0.5mm thick lithium sheet, and 0.5mm thick stainless steel sheet and spring are stacked in sequence.

[0031] All assembled batteries were left to stand at 60°C for 6 hours to promote full contact at the electrode / electrolyte interface, after which electrochemical tests were performed.

[0032] Pouch Battery Assembly: Cut the positive electrode sheet into a 6cm × 5cm rectangle, and cut the solid electrolyte membrane and lithium foil into 6.5cm × 4.5cm dimensions respectively. Prepare copper foil current collectors of the same size. Solder the aluminum tabs to the LFP electrode sheet and the nickel tabs to the copper foil. Align the battery stack in the following order: positive electrode sheet—electrolyte membrane—lithium foil—copper foil, with all tabs on the same side. Pack the stacked cells into an aluminum-plastic film packaging bag and seal it multiple times using a heat sealer to ensure an internal vacuum environment.

[0033] Comparative Example 2 Solid electrolyte membranes were prepared by solution casting, with the following specific steps: First, polyacrylonitrile (PAN), succinic anionyl nitrile (SN), and lithium perchlorate (LiClO4) were accurately weighed according to a mass ratio of m(PAN):m(SN):m(LiClO4) = 4:1:2, and dissolved together in N,N-dimethylformamide (DMF) solvent. Then, an additional 3% by mass of g [unspecified ingredient] was added. - C3N4 was used as an interface stabilizer. The mixed solution was then placed in an oil bath at 80°C and continuously mechanically stirred for 10 hours to ensure complete dissolution and reaction, ultimately obtaining a uniform, transparent, viscous slurry. Afterward, the slurry was allowed to stand for a period to remove internal air bubbles, and then uniformly coated onto a clean glass substrate using a precision coater to form a wet film. Next, the sample was transferred to a vacuum drying oven at 80°C and dried for 12 hours to completely remove the DMF solvent, forming a dense and self-supporting PAN-SN composite modified solid polymer electrolyte membrane. Finally, the prepared electrolyte membrane was cut into 19mm diameter discs using a cutting machine and stored in a dry environment for subsequent battery assembly and electrochemical testing.

[0034] Preparation of the positive electrode: NCM, acetylene black, LiTFSI, PVDF, and SN were weighed in a mass ratio of 80:10:10:10:5 and dispersed together in N-methylpyrrolidone (NMP) solvent. The mixture was magnetically stirred for 12 hours to ensure thorough dispersion and uniform mixing, followed by standing for 2 hours to remove air bubbles. Then, it was uniformly coated onto the surface of an aluminum foil current collector using a doctor blade coating process. The coated electrode was then dried in an 80°C vacuum oven for 24 hours to completely remove the solvent. Finally, the dried electrode was cut into 8mm diameter discs, yielding a positive electrode active material areal loading of approximately 2.4 mg•cm⁻², for subsequent battery assembly.

[0035] Assembly of button cells: All cells use 2032 button cell cases and are assembled in an argon atmosphere glove box. The oxygen and moisture content in the operating environment is below 0.1 ppm.

[0036] AC impedance test battery: The structure consists of a 0.5mm thick stainless steel sheet (positive electrode side), a solid electrolyte membrane, a 1mm thick stainless steel sheet, and a stainless steel spring sheet (negative electrode side). Lithium symmetric battery cycle test: Two 0.5mm thick lithium sheets are used to contact the two sides of the solid electrolyte membrane respectively, and the outer side is supplemented with a 0.5mm stainless steel sheet and a spring sheet to complete the encapsulation; Full cell cycle test: The positive electrode, solid electrolyte membrane, 0.5mm thick lithium sheet, and 0.5mm thick stainless steel sheet and spring are stacked in sequence.

[0037] All assembled batteries were left to stand at 60°C for 6 hours to promote full contact at the electrode / electrolyte interface, after which electrochemical tests were performed.

[0038] Pouch Battery Assembly: Cut the positive electrode sheet into a 6cm × 5cm rectangle, and cut the solid electrolyte membrane and lithium foil into 6.5cm × 4.5cm dimensions respectively. Prepare copper foil current collectors of the same size. Solder the aluminum tabs to the LFP electrode sheet and the nickel tabs to the copper foil. Align the battery stack in the following order: positive electrode sheet—electrolyte membrane—lithium foil—copper foil, with all tabs on the same side. Pack the stacked cells into an aluminum-plastic film packaging bag and seal it multiple times using a heat sealer to ensure an internal vacuum environment.

[0039] Results and Analysis The charge transfer resistance of different lithium / electrolyte interfaces was characterized by electrochemical impedance spectroscopy, and the results are as follows: Figure 1As shown in Figure 1, Figure 1(a) is the full EIS spectrum, and Figure 1(b) is a magnified view of the lower left region of Figure 1(a). The results show that the EIS curves of all batteries exhibit a semi-circular shape followed by a linear tail. The starting point of the high-frequency region of the spectrum corresponds to the bulk resistance of the electrolyte (Rb = RΩ), while the large capacitive arc appearing in the mid-frequency region corresponds to the total charge transfer impedance at the lithium / electrolyte interface (Ri = Rct1 + Rct2). Since both interfaces in the symmetrical battery structure participate in the parallel charge transfer process, the measured total resistance needs to be divided by 2 to calculate the resistance value corresponding to a single interface. In Comparative Example 2 (using a PAN electrolyte membrane), the Li / PAN / Li battery has a Li / PAN interface resistance of approximately 850 Ω•cm². This is mainly due to the high brittleness and rigidity of the dry lithium-containing PAN electrolyte membrane, resulting in poor interfacial compatibility with the electrodes. The Li / PAN-SN / Li battery assembled in Comparative Example 1 (using a PAN-SN electrolyte membrane) showed a significant reduction in interface resistance to approximately 76 Ω•cm²; the Li / PAN-SNL / Li battery assembled in Example 1 (using a PAN-SNL composite modified solid electrolyte membrane) showed a further reduction in interface resistance to approximately 67 Ω•cm². The interface resistance of Example 1 was not only much lower than that of Comparative Example 2, but also slightly better than that of Comparative Example 1. This is attributed to the tighter contact between the electrolyte and the lithium electrode, as well as the more efficient migration of lithium ions in the solid electrolyte LLZTO.

[0040] The cycling stability and interfacial impedance evolution of the Li / PAN-SNL / Li symmetric battery prepared in Example 1 were characterized by electrochemical testing, and the results are shown in Figure 2. Figure 2(a) shows the voltage-time cycling curve of the battery at 30℃ and a current density of 0.1 mA·cm⁻², and Figure 2(b) shows a comparison of the electrochemical impedance spectroscopy (EIS) after the first and 700th cycles. As can be seen from Figure 2(a), the symmetric battery can maintain stable cycling for over 700 hours, and the overpotential remains consistently at approximately 18 mV, exhibiting excellent cycling stability. Combined with Figure 2(b), after 700 cycles, the battery impedance did not show a significant change, indicating that the synergistic effect of SN and related components in the system effectively constructs a stable Li / electrolyte interface, ensuring long-term cycling performance.

[0041] To realize the practical application of solid-state lithium batteries, the mass loading of the cathode needs to be significantly increased. Based on the requirements for efficient lithium-ion transport in the full cell and a stable Li / electrolyte interface, the mass loading of the cathode (SN, g) is increased. -The modification strategy of C3N4 and LLZTO solid electrolyte to PAN electrolyte has been successfully applied to high-load solid-state battery systems. Figure 3 shows the electrochemical performance test results of the NCM / PAN-SNL / Li battery assembled in Example 1 with a positive electrode loading of approximately 6.2 mg・cm⁻² at 30℃ and a cutoff voltage of 4.2 V. Figure 3(a) is the charge-discharge curve of the battery at 0.5C, and Figure 3(b) is the curve of the specific capacity and coulombic efficiency as a function of cycle number. The test shows that the battery achieves an initial discharge capacity of approximately 0.9 mAh・cm⁻² (equivalent to 145 mAh・g⁻¹) and maintains excellent capacity retention performance after 40 cycles, indicating that the modification strategy effectively optimizes the electrochemical performance of the battery under high-load conditions.

[0042] Furthermore, an NCM / PAN-SNL / Li pouch cell was also fabricated, which exhibited good flexibility and could withstand a certain degree of bending deformation. As shown in Figure 4, regardless of whether it is on a flat surface (… Figure 4 a) Still in a bent state ( Figure 4 (b) The pouch battery provides a stable power supply, enabling the LED lights to illuminate normally. It is worth noting that even when partially cut off in an open environment ( Figure 4 (c) The battery remained operational, successfully lighting the LED. These results clearly demonstrate that the pouch cell based on the SN / LiNO3-modified PAN polymer electrolyte exhibits significant potential for advancing the practical application of solid-state lithium batteries.

[0043] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An all-solid-state oxide-polymer electrolyte membrane, characterized in that, The electrolyte membrane comprises a polymer matrix, a lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride. The polymer matrix, lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride are uniformly mixed to form a solid film. The polymer matrix is ​​polyacrylonitrile, which constitutes the framework of the electrolyte membrane. The lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride are at least physically uniformly dispersed in the polymer matrix.

2. The all-solid-state oxide-polymer electrolyte membrane according to claim 1, characterized in that, The lithium salt is lithium perchlorate.

3. The all-solid-state oxide-polymer electrolyte membrane according to claim 1 or 2, characterized in that, The mass ratio of the polymer matrix, lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide and graphitic carbon nitride is (3~5): (1~3): (1~2): (2~5): (0.01~0.06).

4. The all-solid-state oxide-polymer electrolyte membrane according to claim 3, characterized in that, The mass ratio of the polymer matrix, lithium salt, succinic anion, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride is 4: 2: 1: 3: 0.

03.

5. A method for preparing an all-solid-state oxide-polymer electrolyte membrane, characterized in that, The polymer matrix, lithium salt, succinate, lithium lanthanum zirconium tantalum oxide, and graphitic carbon nitride are mixed in an organic solvent to form a uniform slurry, which is then formed into a film and dried to obtain the all-solid oxide-polymer electrolyte membrane.

6. The preparation method according to claim 5, characterized in that, The all-solid-state oxide-polymer electrolyte membrane is the electrolyte membrane according to any one of claims 1-4, and the preparation method includes the following steps: (1) Slurry preparation: The polymer matrix, lithium salt, succinate, lithium lanthanum zirconium tantalum oxide and graphitic carbon nitride are dispersed together in an organic solvent and the components are thoroughly mixed by mechanical stirring to form a stable and uniform slurry system. (2) Degassing treatment: The slurry obtained in step (1) is allowed to stand or centrifuged or depressurized to remove the air bubbles entrained therein, so as to obtain a dense slurry; (3) Film forming process: The degassed slurry is cast or coated onto a clean substrate to form a wet film of uniform thickness; (4) Drying and curing: The wet film obtained in step (3) is dried under heating and / or negative pressure conditions to remove organic solvents and form a dense solid electrolyte membrane with self-supporting properties, thus obtaining the all-solid oxide-polymer electrolyte membrane.

7. The preparation method according to claim 6, characterized in that, The organic solvent mentioned in step (1) is N,N-dimethylformamide.

8. The application of an all-solid-state oxide-polymer electrolyte membrane as described in any one of claims 1-4 in the preparation of solid-state lithium batteries.

9. The application according to claim 8, characterized in that, The solid-state lithium battery is an all-solid-state battery with lithium metal as the negative electrode, and its structure includes, in sequence, a positive electrode, the all-solid-state oxide-polymer electrolyte membrane, and a lithium metal negative electrode.

10. The application according to claim 8, characterized in that, The solid-state lithium battery is a flexible pouch battery, the structure of which includes a cell composed of a positive electrode, the all-solid-state oxide-polymer electrolyte membrane and a lithium metal negative electrode stack, and a flexible packaging shell for encapsulating the cell.

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