A polymer solid-state electrolyte, a preparation method thereof, and a battery

Abstract

The application provides a polymer solid electrolyte, a preparation method thereof and a battery. The preparation method of the polymer solid electrolyte comprises the following steps: (1) stirring lithium salt and a functional compound at a first temperature until the lithium salt and the functional compound are transparent and uniform, to obtain a transparent solution, wherein the functional compound is at least one selected from 2,2-difluoroethyl acetate and butyrolactam; (2) mixing fluorine-containing monomers, ether-containing monomers and a crosslinking agent at room temperature to obtain a polymerization solution; (3) mixing the transparent solution and the polymerization solution, and then adding an initiator to obtain a prepolymer solution; and (4) injecting the prepolymer solution into a battery to generate an in-situ polymerization reaction at a second temperature. Through in-situ thermal polymerization and phase separation regulation, a double-continuous phase structure is successfully constructed, and perfect combination of ion conduction and mechanical support is realized.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, specifically providing a polymer solid electrolyte, its preparation method, and a battery. Background Technology

[0002] With the increasing demand for high-energy-density, high-safety, and long-cycle-life batteries in portable electronic devices, electric vehicles, and large-scale energy storage systems, lithium metal battery (LMB) technology has received widespread attention. While traditional liquid electrolyte lithium-ion batteries offer high energy density, their safety issues, particularly the flammability and potential leakage risks of liquid electrolytes, severely limit their use in broader applications. Therefore, solid-state electrolytes are considered key materials for next-generation high-energy-density batteries, as they can effectively suppress lithium dendrite growth and improve battery safety. However, all-solid-state electrolytes face challenges such as low ionic conductivity and high interfacial impedance.

[0003] Polymer electrolytes are considered promising alternatives due to their good flexibility and processability, but traditional polyethylene oxide (PEO)-based electrolytes have low room-temperature ionic conductivity (<10). -4 Furthermore, the electrochemical window is narrow, making it unsuitable for high-voltage cathode materials. Traditional elasto-plastic polymer electrolytes are typically prepared using simple physical mixing methods, resulting in weak interfacial bonding between the plastic crystals and elastomers, severe phase separation, discontinuous ion conduction pathways, and the inability to form a stable two-phase interface, thus limiting improvements in ionic conductivity and mechanical properties. In addition, due to the mismatch in thermal expansion coefficients between the plastic crystals and elastomers, internal stress is easily generated during battery cycling, leading to electrolyte layer rupture and ultimately battery failure.

[0004] Therefore, existing polymer electrolytes need to be improved. Summary of the Invention

[0005] This invention aims to at least partially address one of the technical problems in the prior art. Therefore, one objective of this invention is to provide a polymer solid electrolyte, its preparation method, and a battery thereof, to solve the problem that existing polymer solid electrolytes struggle to simultaneously achieve high ionic conductivity and mechanical properties. This improves the ionic conductivity and electrochemical window stability of the electrolyte, ensuring stable operation at high temperatures, while simultaneously enhancing the mechanical strength of the electrolyte to prevent breakage and deformation during use, thus adapting to different types of positive and negative electrode materials and improving the overall battery performance.

[0006] In a first aspect, the present invention provides a method for preparing a polymer solid electrolyte, comprising: (1) The lithium salt and the functional compound are stirred at a first temperature until they become transparent and homogeneous to obtain a transparent solution, wherein the functional compound is selected from at least one of 2,2-difluoroethyl acetate ((DA)) and butyrolactam (BL); (2) Fluorine-containing monomers, ether-containing monomers and crosslinking agents are mixed at room temperature to obtain a polymerization solution; (3) After mixing the transparent solution and the polymerization liquid, an initiator is added to obtain a prepolymer solution; (4) The prepolymer liquid is injected into the battery to undergo in-situ polymerization at a second temperature.

[0007] The present invention provides a method for preparing a polymer solid electrolyte using specific functional compounds. This allows for the regulation of the separation behavior between the polymer phase and the transparent solution phase during polymerization, forming an interpenetrating, continuously distributed two-phase network structure that provides continuous ion transport channels. The mechanically supporting phase formed by crosslinking of the polymerization liquid provides mechanical strength and interfacial stability. The present invention combines a transparent solution with an elastomeric polymer matrix through in-situ polymerization to obtain a polymer electrolyte with a bicontinuous phase structure. Furthermore, the present invention uses fluorinated and etherified monomers to prepare the polymer. The etherified monomers provide compliant ether-oxygen bonds, promoting lithium ion dissociation and transport, and ensuring high ionic conductivity; the fluorinated monomers increase the antioxidant potential and induce the formation of a stable LiF-rich interfacial film, inhibiting lithium dendrite formation. The copolymerization of these two monomers endows the polymer with both high conductivity and high stability. When further combined with lithium salts and their solvents, hydrogen bonds and "fluorine-fluorine" affinity interactions are formed, which can not only disrupt the polymer crystallization region and enhance ion channels, but also form a leak-proof quasi-solid electrolyte. At the same time, a dense gradient interface film is synergistically constructed, thereby achieving a synergistic effect of high conductivity, wide voltage window, dendrite suppression and long cycle life.

[0008] Therefore, this solid electrolyte can balance ion conductivity and mechanical properties, achieving synergistic optimization of ion conduction channels and mechanical support networks, and providing a new solution for the development of high-energy-density solid lithium metal batteries.

[0009] In some embodiments of the present invention, in step (1), the molar ratio of the lithium salt to the functional compound is 1:(2~5). For example, the molar ratio of the lithium salt to the functional compound is 1:2, 1:3, 1:4, 1:5, etc., or any range between the above two values. Controlling the addition amount of both within the above range ensures that the lithium-containing solvent has a sufficient lithium ion concentration to provide high ionic conductivity, while avoiding incomplete dissolution or excessive system viscosity due to an excessively high lithium salt ratio; at the same time, it prevents insufficient charge carriers and low conductivity due to an excessively low lithium salt ratio. Within this molar ratio range, a stable and uniform lithium-ion-rich solvent can be formed, resulting in optimal overall performance.

[0010] In some embodiments of the present invention, the first temperature is 50~80°C.

[0011] In some embodiments of the present invention, in step (1), the transparent solution further includes an electrolyte additive.

[0012] Furthermore, the amount of electrolyte additive added is 5% to 10% of the total mass of the lithium salt and the functional compound.

[0013] In some embodiments of the present invention, the electrolyte additive includes at least one of fluoroethylene carbonate (FEC), ethylene ethylene carbonate (VEC), and ethylene carbonate (VC).

[0014] In some embodiments of the present invention, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), and lithium bis(oxalatoborate) (LiBOB).

[0015] In some embodiments of the present invention, the fluorinated monomer includes at least one of 2-(perfluorobutyl)ethyl methacrylate (HFBA), 2,2,3,3,3-pentafluoropropyl acrylate (PPA), vinylidene fluoride (VDF), and hexafluoropropylene (HFP).

[0016] In some embodiments of the present invention, the ether-containing monomer includes at least one of tetrahydrofuran methacrylate (THFMA), 2-(2-(2-methoxyethoxy)ethoxy)ethyl acrylate (MEA), methoxyethyl methacrylate (EEOEMA), and ethoxyethyl acrylate (EOA).

[0017] In some embodiments of the present invention, the crosslinking agent includes at least one of polyethylene glycol dimethacrylate (PEGDMA), N,N'-methylenebisacrylamide (MBAA), and carbodiimide compounds.

[0018] In some embodiments of the present invention, the molar ratio of the ether-containing monomer to the fluorine-containing monomer is (5~7):3. For example, the molar ratio of the ether-containing monomer to the fluorine-containing monomer is 5:3, 6:3, 7:3, etc., or any range between the two values ​​mentioned above. Controlling the molar ratio of the ether-containing monomer to the fluorine-containing monomer within the above range can balance ionic conductivity and electrochemical stability: if the proportion of the ether-containing monomer is too low, there are insufficient ether-oxygen bonds, and ion transport is hindered; if the proportion of the fluorine-containing monomer is too low, the polymer's antioxidant potential decreases, making it difficult to match the high-voltage cathode. The preferred monomer molar ratio of the present invention can retain sufficient ether-oxygen bonds to ensure efficient lithium-ion conduction, while introducing an appropriate amount of fluorine-containing segments to improve high-voltage resistance (≥5.0 V) and induce the formation of a LiF-rich interface film, while forming a "rigid and flexible" micro-phase separation structure, achieving the best balance between ionic conductivity and high-voltage stability.

[0019] In some embodiments of the present invention, the amount of crosslinking agent added is 1 to 3% of the total mass of the ether-containing monomer and the fluorine-containing monomer.

[0020] In some embodiments of the present invention, in step (3), the volume ratio of the transparent solution to the polymer solution is (30~70):(70~30), preferably (45~55):(55~45). For example, the volume ratio of the transparent solution to the polymer solution is 30:70, 30:60, 30:50, 30:40, 30:30, 70:00, 60:30, 50:30, 40:30, etc., or any range between any two of the above values. Controlling the volume ratio of the transparent solution to the polymer solution within the above range can balance ionic conductivity and mechanical strength, achieving a synergistic balance between "skeleton support" and "ion channels". If the proportion of transparent solution is too low (i.e., the proportion of polymer solution is too high), the polymer skeleton occupies the main body, the free volume provided by the lithium solvent is insufficient, and lithium ions lack sufficient transport medium, resulting in a decrease in ionic conductivity and failing to meet the rate performance requirements of the battery. Conversely, if the proportion of transparent solution is too high and the polymer content is insufficient, on the one hand, the mechanical strength of the formed gel or quasi-solid electrolyte will be significantly reduced, making it difficult to maintain the integrity of the self-supporting membrane and prone to cracking or deformation; on the other hand, excessive lithium-containing solvent may exceed the adsorption and anchoring capacity of the polymer, leading to phase separation or solvent precipitation, which will damage the homogeneity and interfacial stability of the system.

[0021] In some embodiments of the present invention, the initiator includes a thermal initiator, the amount of which is 0.8-2% of the total mass of the transparent solution and the polymerization liquid. Preferably, the thermal initiator includes at least one of benzoyl peroxide (BPO), ammonium persulfate (APS), and azobisisobutyronitrile (AIBN).

[0022] In some embodiments of the present invention, in step (4), the second temperature is 70~80°C.

[0023] In some embodiments of the present invention, the in-situ polymerization reaction takes 0.5 to 2 hours.

[0024] In some embodiments of the present invention, the in-situ polymerization reaction is carried out under the protection of an inert atmosphere.

[0025] In a second aspect, the present invention provides a polymer solid electrolyte prepared by the above-described method. Therefore, the polymer solid electrolyte provided by the present invention exhibits excellent ionic conductivity and mechanical properties.

[0026] In a third aspect, the present invention provides a battery comprising the aforementioned polymer solid electrolyte. Therefore, the battery provided by the present invention exhibits excellent rate performance, cycle performance, and lifespan.

[0027] Furthermore, the battery also includes a positive electrode and a negative electrode.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: (1) This invention provides a bicontinuous phase structure that is successfully constructed by using specific functional compounds through in-situ thermal polymerization and phase separation control, achieving a perfect combination of ion conduction and mechanical support. The constructed bicontinuous structure has extremely low tortuosity (τ≈2.0), providing a continuous ion transport channel, enabling the electrolyte to have high ionic conductivity (≥1.6 mS / cm) at room temperature.

[0029] (2) The local lithium-ion concentration in the dual continuous structure constructed in this invention is high, which promotes lithium-ion hopping conduction and gives the electrolyte a high lithium-ion transference number (≥0.75). The interpenetrating elastomer network provides excellent mechanical properties (elongation at break ≥300%), which can effectively suppress lithium dendrite growth. The dual continuous structure provides a stable electrode / electrolyte interface and effectively suppresses interfacial side reactions. It is suitable for high-voltage positive electrodes (such as NMC-83) and lithium metal negative electrodes. The assembled full cell exhibits excellent cycle stability (capacity retention >80% after 200 cycles at 0.5C rate) and rate performance.

[0030] (3) The thermally initiated in-situ polymerization process provided by the present invention is simple, easy to operate, environmentally friendly, and does not require organic solvents, making it suitable for large-scale production. Attached Figure Description

[0031] Figure 1 SEM image of the solid electrolyte membrane provided by this invention. Detailed Implementation

[0032] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the invention in any way.

[0033] Example 1 (1) In an argon glove box, LiTFSI and DA are mixed at a molar ratio of 1:4 and stirred at 60°C until a transparent and uniform liquid is formed to obtain a liquid electrolyte solution; (2) In an argon glove box, PPA and EOA (molar ratio 3:7) are mixed evenly, and then 1% of the total mass of PEGDMA is added as a crosslinking agent. The mixture is stirred at room temperature until it becomes a transparent and uniform liquid to obtain a polymer precursor solution. (3) In an argon glove box, the liquid electrolyte solution and the polymer precursor solution are mixed evenly in a volume ratio of 50:50, and then 1.5% of the total mass of the monomers, AIBN, is added as a thermal initiator. The mixture is stirred at room temperature until a transparent and uniform liquid is obtained to obtain the prepolymer solution. (4) In a strictly anhydrous and oxygen-free glove box, first place the ternary material positive electrode sheet (such as NCM or NCA) at the bottom of the battery mold, and then pour the pre-prepared DP50 prepolymer liquid onto the positive electrode surface; then precisely align the composite positive electrode sheet with the lithium metal negative electrode sheet, and apply a slight pressure of 0.5-1 MPa to ensure that the prepolymer liquid fully wets the porous structure of the positive electrode and forms a uniform interface; then assemble the entire assembly according to the assembly method of liquid batteries, transfer it to an oven, and thermally initiate polymerization at 70-80℃ for 0.5-2 hours, so that the ether / fluorine monomers undergo free radical polymerization under the action of the initiator, and the crosslinking agent forms a three-dimensional network structure, and finally generate in situ on the positive electrode surface with high ionic conductivity (ether bonds provide Li + A polymer solid electrolyte layer with excellent electrochemical stability (fluorine-containing groups enhance oxidation resistance) and a transport channel are formed. At the same time, the introduction of liquid electrolyte solution induces phase separation, forming a polymer electrolyte with a bicontinuous structure. After cooling to room temperature, the solid-state battery is assembled. The electrolyte layer is tightly bonded to the ternary cathode interface through chemical bonding, effectively suppressing interfacial side reactions and improving the battery cycle stability.

[0034] Example 2 (1) In an argon glove box, LiTFSI and BL are mixed at a molar ratio of 1:4 and stirred at 60°C until a transparent and uniform liquid is formed to obtain a liquid electrolyte solution; (2) In an argon glove box, PPA and EOA (molar ratio 3:7) are mixed evenly, and then 1% of the total mass of PEGDMA is added as a crosslinking agent. The mixture is stirred at room temperature until it becomes a transparent and uniform liquid to obtain a polymer precursor solution. (3) In an argon glove box, the liquid electrolyte solution and the polymer precursor solution are mixed evenly in a volume ratio of 50:50, and then 1.5% of the total mass of the monomers, AIBN, is added as a thermal initiator. The mixture is stirred at room temperature until a transparent and uniform liquid is obtained to obtain the prepolymer solution. (4) In a strictly anhydrous and oxygen-free glove box, first place the ternary material positive electrode sheet (such as NCM or NCA) at the bottom of the battery mold, and then pour the pre-prepared DP50 prepolymer liquid onto the positive electrode surface; then precisely align the composite positive electrode sheet with the lithium metal negative electrode sheet, and apply a slight pressure of 0.5-1 MPa to ensure that the prepolymer liquid fully wets the porous structure of the positive electrode and forms a uniform interface; then assemble the entire assembly according to the assembly method of liquid batteries, transfer it to an oven, and thermally initiate polymerization at 70-80℃ for 0.5-2 hours, so that the ether / fluorine monomers undergo free radical polymerization under the action of the initiator, and the crosslinking agent forms a three-dimensional network structure, and finally generate in situ on the positive electrode surface with high ionic conductivity (ether bonds provide Li + A polymer solid electrolyte layer with excellent electrochemical stability (fluorine-containing groups enhance oxidation resistance) and a transport channel are formed. At the same time, the introduction of liquid electrolyte solution induces phase separation, forming a polymer electrolyte with a bicontinuous structure. After cooling to room temperature, the solid-state battery is assembled. The electrolyte layer is tightly bonded to the ternary cathode interface through chemical bonding, effectively suppressing interfacial side reactions and improving the battery cycle stability.

[0035] Example 3 The difference between Example 3 and Example 1 is that the volume ratio of the liquid electrolyte solution to the polymer precursor solution in Example 3 is 60:40.

[0036] Example 4 The difference between Example 4 and Example 1 is that the volume ratio of the liquid electrolyte solution to the polymer precursor solution in Example 4 is 40:60.

[0037] Comparative Example 1 Comparative Example 1 uses only the liquid electrolyte solution from Example 1. It is assembled into a battery according to the assembly method of a liquid battery, without the need to add polymer precursor solution. The rest is the same as in Example 1.

[0038] Comparative Example 2 In an argon glove box, PPA and EOA (molar ratio 3:7) were mixed thoroughly, and then 1% of the total monomer mass of PEGDMA was added as a crosslinking agent, along with a certain amount of lithium salt (to ensure the molar ratio EO:Li). + =16:1), and stirred at room temperature until a transparent and homogeneous liquid is obtained to obtain the prepolymer solution; The remaining steps for in-situ polymerization assembly of solid-state batteries are the same as in Example 1.

[0039] Comparative Example 3 Prepare bicontinuous electrolytes polymerized in situ.

[0040] Electrolytes were prepared by solution casting: the prepolymer liquid of Example 1 was coated onto a polytetrafluoroethylene plate, thermally initiated polymerization was followed by peeling to obtain an independent electrolyte membrane, which was then assembled with electrodes to form a battery.

[0041] The performance of the solid electrolytes and batteries in the examples and comparative examples was measured, and the specific measurement results are shown in Table 1.

[0042] Table 1

[0043] As can be seen from the results in Table 1, the polymer solid electrolyte (BA50) with the optimal bicontinuous phase structure prepared in Examples 1 and 2 of this invention exhibits the best overall performance: high ionic conductivity, high lithium-ion transference number, low tortuosity, excellent mechanical properties, and a wide electrochemical window. Example 3 showed a relatively high ionic conductivity (1.32 mS / cm), but the lithium-ion transference number (0.53), elongation at break (160%), and capacity retention (45.6%) decreased significantly. This was because the excessively high proportion of liquid electrolyte solution resulted in insufficient flexibility of the polymer network and weakened interfacial stability, leading to deteriorated cycling performance. Example 4 showed a relatively low ionic conductivity (0.28 mS / cm), poor tortuosity (6.7) and elongation at break (280%), and moderate capacity retention (76.3%). This was because the excessively high proportion of polymer precursor solution restricted the ion conduction pathway, making the electrolyte more brittle. Although it exhibited some cycling stability, its overall performance was weaker than that of Example 1. Comparative Example 2 did not add the functional compounds of the present invention; it only physically composited a fluorinated-ether copolymer with a conventional lithium salt. The system lacked sufficient functional compounds as plasticizers and ion transport media. On the one hand, the proportion of amorphous phase in the polymer matrix was insufficient, with a large number of chain segments in a crystalline state, leading to obstruction of ion transport channels. On the other hand, conventional lithium salts were difficult to fully dissociate and uniformly disperse in the polymer, resulting in a significant decrease in ionic conductivity. Furthermore, the single polymer-lithium salt system lacked effective protection for the high-voltage cathode, had a narrow electrochemical stability window, and exhibited severe interfacial side reactions. Therefore, Comparative Example 2 was significantly inferior to Example 1 in terms of room temperature ionic conductivity, rate performance, and cycle life. Comparative Example 3 used the same formulation but employed a pre-polymerization followed by battery assembly method (non-in-situ polymerization), yet its overall performance was still weaker than Example 1. This is because the non-in-situ prepared polymer film has a simple physical stacking contact with the electrode; the rigid contact at the solid-solid interface leads to numerous microscopic voids and insufficient contact, significantly increasing interfacial impedance. After battery assembly, the actual ion transport efficiency between the electrolyte membrane and the electrode is far lower than the ideal interface, and the ineffective contact areas at the interface easily induce preferential nucleation and growth of lithium dendrites. In contrast, Example 1, through an in-situ polymerization strategy, allows the liquid precursor to be directly solidified inside the battery, and the polymer network forms a chemical complex or tight wetting contact with the electrode surface, achieving a truly "integrated" interface structure. Therefore, although Comparative Example 3 has the same composition as Example 1, its poor interface compatibility and high interface impedance result in lower rate performance and cycle stability than Example 1.

[0044] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0045] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a polymer solid electrolyte, characterized in that, include: (1) The lithium salt and the functional compound are stirred at a first temperature until they become transparent and homogeneous to obtain a transparent solution, wherein the functional compound is selected from at least one of 2,2-difluoroethyl acetate and butyrolactam; (2) Fluorine-containing monomers, ether-containing monomers and crosslinking agents are mixed at room temperature to obtain a polymerization solution; (3) After mixing the transparent solution and the polymerization liquid, an initiator is added to obtain a prepolymer solution; (4) The prepolymer liquid is injected into the battery to undergo in-situ polymerization at a second temperature.

2. The method according to claim 1, characterized in that, In step (1), the molar ratio of the lithium salt to the functional compound is 1:(2~5). And / or, the first temperature is 50~80℃.

3. The method according to claim 1, characterized in that, In step (1), the transparent solution also includes an electrolyte additive; And / or, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, and lithium bis(oxalatoborate).

4. The method according to claim 3, characterized in that, The amount of the electrolyte additive added is 5% to 10% of the total mass of the lithium salt and the functional compound; And / or, the electrolyte additive includes at least one of fluoroethylene carbonate, ethylene ethylene carbonate, and ethylene carbonate.

5. The method according to any one of claims 1-4, characterized in that, The fluorinated monomer includes at least one of 2-(perfluorobutyl)ethyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, vinylidene fluoride, and hexafluoropropylene. And / or, the ether-containing monomer includes at least one of tetrahydrofuran methacrylate, 2-(2-(2-methoxyethoxy)ethoxy)ethyl acrylate, methoxyethyl methacrylate, and ethoxyethyl acrylate; And / or, the crosslinking agent includes at least one of polyethylene glycol dimethacrylate, N,N'-methylenebisacrylamide, and carbodiimide compounds.

6. The method according to any one of claims 1-4, characterized in that, The molar ratio of the ether-containing monomer to the fluorine-containing monomer is (5~7):3; And / or, the amount of the crosslinking agent added is 1 to 3% of the total mass of the ether-containing monomer and the fluorine-containing monomer.

7. The method according to any one of claims 1-4, characterized in that, In step (3), the volume ratio of the transparent solution to the polymer solution is (30~70):(70~30), preferably (45~55):(55~45); And / or, the initiator includes a thermal initiator, the amount of which is 0.8 to 2% of the total mass of the transparent solution and the polymerization liquid, preferably the thermal initiator includes at least one of benzoyl peroxide, ammonium persulfate, and azobisisobutyronitrile.

8. The method according to any one of claims 1-4, characterized in that, In step (4), the second temperature is 70~80℃; And / or, the in-situ polymerization reaction takes 0.5 to 2 hours; And / or, the in-situ polymerization reaction is carried out under the protection of an inert atmosphere.

9. A polymer solid electrolyte, characterized in that, It is prepared by any one of the methods described in claims 1-8.

10. A battery, characterized in that, Includes the polymer solid electrolyte of claim 9.

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