Method for preparing all-solid-state battery through liquid solvent-free in-situ thermal crosslinking

Abstract

The invention belongs to the technical field of all-solid-state batteries, and particularly relates to a process for preparing all-solid-state polymer electrolyte through solvent-free in-situ thermal crosslinking. The invention provides a preparation method of an all-solid-state battery, which comprises the following steps: firstly preparing electrolyte precursor slurry, then covering the surfaces of a positive plate and a negative plate with the obtained precursor slurry, then packaging in a battery shell, and finally heating at 150-350 DEG C for 2 minutes to 24 hours for crosslinking to obtain the all-solid-state battery, wherein the raw materials of the electrolyte precursor slurry comprise a polymer and a lithium salt, and the polymer is a polymer which has a thermal cross-linking structure in a molecular chain and is in a liquid state at normal temperature. According to the invention, the battery with high ionic conductivity is prepared without introducing a solvent and an initiator.

Description

Technical Field

[0001] The present invention belongs to the technical field of all-solid-state batteries, and in particular relates to a process for preparing an all-solid-state polymer electrolyte by solvent-free in-situ thermal cross-linking. Background Art

[0002] As a high-energy-density energy storage device, lithium batteries are widely used in fields such as smartphones, laptops, and electric vehicles. However, liquid lithium batteries currently have safety issues, especially the flammability of liquid electrolytes, which may lead to serious safety hazards. Solid-state electrolytes, as an emerging technical solution, have the advantages of high ionic conductivity, good safety, and high-temperature resistance. They are expected to solve the safety issues of liquid lithium batteries and further improve battery performance. Among them, polymer solid electrolytes, as an excellent candidate material, have advantages such as good mechanical properties, low solid-solid interface resistance, and excellent chemical stability, providing a bright prospect for solving the safety issues of liquid lithium batteries.

[0003] However, most current solid polymer electrolyte forming processes involve pre-film formation and then compounding with the battery's positive and negative electrodes. The process is then wound or laminated to form a battery. This results in a very large solid / solid interface impedance between the battery electrodes and the solid electrolyte, resulting in relatively poor charge / discharge performance, rate capability, and cycle performance of the solid-state battery. Patent application CN 111944099A discloses a method and application for preparing a fully solid polymer electrolyte by in-situ thermal initiation. A mixed solution consisting of a polyethyleneimine polymer, an unsaturated end-group ester, a salt, and a solvent is placed in a sealed container and subjected to in-situ thermal initiation crosslinking without the addition of an initiator to form a polymer electrolyte. However, such methods require the addition of a separate solvent system, otherwise the reaction will not proceed normally. The volatilization of the solvent introduces a certain amount of voids, reducing the density and uniformity of the electrolyte membrane and increasing the production cost of the polymer electrolyte. Patent application CN114597487A discloses a method for preparing a solvent-free solid electrolyte membrane by uniformly dispersing a solid electrolyte within a cross-linked network structure of a polymer binder. The presence of residual initiator in the electrolyte can adversely affect the electrochemical properties of the polymer electrolyte, thereby reducing battery performance and lifespan. Residual initiator not only affects battery performance but can also pose a health hazard to humans. Summary of the Invention

[0004] The present invention provides a method for preparing an all-solid-state battery, which comprises using a liquid heat-crosslinkable polymer as a raw material, introducing a conductive filler to obtain a solid electrolyte precursor slurry; then directly coating the obtained slurry on the surfaces of positive and negative electrode sheets, and encapsulating them to obtain a battery; finally, heating the battery for reaction, and in-situ forming and curing through high-temperature crosslinking to obtain an integrated all-solid-state battery; thereby achieving the goal of producing a battery with high ionic conductivity without introducing a solvent or an initiator.

[0005] The technical solution of the present invention:

[0006] The first technical problem to be solved by the present invention is to provide a method for preparing an all-solid-state battery. The preparation method is: first prepare an electrolyte precursor slurry, then coat the obtained precursor slurry on the surfaces of the positive electrode sheet and the negative electrode sheet, then encapsulate it in a battery shell, and finally heat it at 150-350°C for 2min-24h for cross-linking to obtain an all-solid-state battery; wherein the raw materials of the electrolyte precursor slurry include a polymer and a lithium salt, and the polymer is a polymer that is liquid at room temperature and has a thermally cross-linkable structure in the molecular chain.

[0007] Furthermore, the mass ratio of the polymer to the lithium salt is (1-99):(99-1).

[0008] Furthermore, the polymer is a copolymer having multiple structural units, including first, second, and third structural units. The first structural unit is derived from at least one cationically polymerizable branched olefin monomer, wherein the branched olefin monomer is selected from isobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene, and combinations thereof; the second structural unit is derived from at least one cationically polymerizable olefin monomer having a benzocyclobutene pendant group; and the third structural unit is a monomer capable of forming glass segments, selected from styrene, indene, α-methylstyrene, p-tert-butylstyrene, or combinations thereof. In other words, the polymer of the present invention may be the polymer disclosed in CN105330775B.

[0009] Furthermore, the first structural unit monomer is isobutylene.

[0010] Furthermore, the second structural unit monomer is 4-vinylbenzocyclobutene.

[0011] Furthermore, the third structural unit monomer is styrene.

[0012] The polymer of the present invention can be prepared by the following method: first, pre-cooling a mixed solvent at -60 to -100°C, then sequentially adding a main initiator, a proton scavenger, a first part of the first monomer isobutylene, and a co-initiator, and polymerizing for 10 to 30 minutes; then adding a second part of the first monomer isobutylene, continuing the polymerization for 50 to 120 minutes, and then adding a mixture of the second monomer styrene and a crosslinking agent dissolved in solvent 1, and polymerizing for 10 to 50 minutes before terminating the reaction.

[0013] Furthermore, the proportions of the raw materials are as follows: the molar ratio of the second monomer to the first monomer is 1:(5-40), the molar ratio of the cross-linking agent to the first monomer is (1-20):(80-99), the concentration of the main initiator is 0.001-1 mol / L (referring to the proportion of the main initiator in the overall reaction system), the molar ratio of the proton scavenger to the main initiator is (1-5):1; the molar ratio of the main initiator to the co-initiator is 1:(16-64); the total molar concentration of the first monomer is 1-10 mol / L (referring to the proportion of the first monomer in the overall reaction system); and the volume ratio of the solvent 1 to the second monomer is (2-6):1.

[0014] Furthermore, the mass ratio of the first part of the first monomer to the second part of the first monomer is: (1-20): (80-99%).

[0015] Furthermore, the mixed solvent is a co-blended solvent of solvent 1 and solvent 2, wherein solvent 1 is selected from at least one of cyclohexane, n-hexane, and methylcyclohexane; and solvent 2 is selected from at least one of chloromethane, dichloromethane, and chloroform.

[0016] Furthermore, the volume ratio of solvent 1 to solvent 2 in the mixed solvent is: (1-5): (1-5).

[0017] Furthermore, the main initiator is 5-tert-butyl-1,3-di(methylethylchloro)benzene. Compared with the HDCE main initiator used in patent US8765895, the main initiator used in the present invention has higher initiation efficiency, fewer side reactions, and the polymerization is active / controllable polymerization, thereby having higher block efficiency and precise block structure.

[0018] Furthermore, the co-initiator is at least one selected from titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkyl aluminum chloride (such as monoethylaluminum dichloride or triethylaluminum trichloride).

[0019] Furthermore, the proton scavenger is a tertiary amine compound, such as a substituted or pentasubstituted aromatic tertiary amine compound, preferably at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine or 2,4,6-tri-tert-butylpyridine.

[0020] Furthermore, the cross-linking agent is selected from: 4-vinylbenzocyclobutene.

[0021] Furthermore, the lithium salt is selected from the group consisting of: lithium perchlorate LiClO4, lithium bis(fluorosulfonyl)imide LiFSI, lithium bis(trifluoromethanesulfonyl)imide LiTFSI and lithium hexafluorophosphate LiPF6, lithium hexafluorophosphate LSICON type sulfide solid electrolyte, LGPS type sulfide solid electrolyte, and thiosilver zirconite type solid electrolyte, or a combination of at least two thereof, preferably lithium bis(trifluoromethanesulfonyl)imide.

[0022] Furthermore, the electrolyte precursor slurry is prepared by the following method: the polymer and lithium salt are mixed uniformly at 10-99° C. to prepare the precursor slurry.

[0023] The second technical problem to be solved by the present invention is to provide an all-solid-state battery, which is prepared using the above-mentioned preparation method.

[0024] The third technical problem to be solved by the present invention is to provide a solid electrolyte membrane, which is prepared by coating an electrolyte precursor slurry on a base membrane and then heating and cross-linking the solid electrolyte membrane; wherein the electrolyte precursor slurry is prepared by the following method: a modified liquid cross-linkable polymer and a lithium salt are uniformly mixed at 10 to 99°C to prepare a precursor slurry.

[0025] Furthermore, the base film material is selected from: polytetrafluoroethylene or polyimide.

[0026] Furthermore, the temperature of the heating cross-linking is 150-350°C.

[0027] Furthermore, the heating cross-linking time is 2 minutes to 24 hours.

[0028] Furthermore, in the method for preparing the precursor slurry, the modified liquid cross-linkable polymer and the lithium salt are mixed by at least one of high-speed vacuum stirring and banburying.

[0029] The fourth technical problem to be solved by the present invention is to point out the application of a polymer that is liquid at room temperature and has a thermally cross-linkable structure in its molecular chain in the preparation of an all-solid-state battery electrolyte.

[0030] Furthermore, the specific method for using a polymer that is liquid at room temperature and has a thermally cross-linkable structure in its molecular chain in the preparation of an all-solid-state battery electrolyte is as follows: first prepare an electrolyte precursor slurry, then coat the obtained precursor slurry on the surface of the positive electrode sheet and the negative electrode sheet, then encapsulate it in a battery shell, and finally heat it at 150-350°C for 2 minutes to 24 hours for cross-linking to obtain an all-solid-state battery.

[0031] Furthermore, the polymer is a copolymer having multiple structural units, including first and second structural units, wherein the first structural unit is derived from at least one cationically polymerizable branched olefin monomer selected from isobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene, and isoolefins combined therefrom; and the second structural unit is derived from at least one cationically polymerizable olefin monomer having a benzocyclobutene pendant group. In other words, the polymer of the present invention may be the polymer disclosed in CN105330775B.

[0032] Furthermore, the polymer is a copolymer having multiple structural units, including first, second, and third structural units. The first structural unit is derived from at least one cationically polymerizable branched olefin monomer, wherein the branched olefin monomer is selected from isobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene, and combinations thereof; the second structural unit is derived from at least one cationically polymerizable olefin monomer having a benzocyclobutene pendant group; and the third structural unit is a monomer capable of forming glass segments, selected from styrene, indene, α-methylstyrene, p-tert-butylstyrene, or combinations thereof. In other words, the polymer of the present invention may be the polymer disclosed in CN105330775B.

[0033] Furthermore, the first structural unit monomer is isobutylene.

[0034] Furthermore, the second structural unit monomer is 4-vinylbenzocyclobutene.

[0035] Furthermore, the third structural unit monomer is styrene.

[0036] Beneficial effects of the present invention:

[0037] 1. The present invention is solvent-free. The modified liquid cross-linkable polymer is liquid at room temperature. There is no need to introduce a separate solvent system to achieve uniform blending with the inorganic conductive filler, thereby avoiding the adverse effects of solvent volatilization.

[0038] 2. No initiator. The modified liquid cross-linkable polymer can achieve self-cross-linking between molecules at high temperature without the addition of initiator; it improves the controllability of the cross-linking reaction, avoids the use of initiators, thereby avoiding initiator residues, improving safety and reducing costs.

[0039] 3. By regulating the monomer ratio, controlling the cross-linking network and the degree of microphase separation, more ion channels can be provided, thereby improving ionic conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Microphase separation diagram of different polystyrene chain segment ratios.

[0041] Figure 2 This is the surface SEM morphology of the solid electrolyte membrane (xSIBS-30M). DETAILED DESCRIPTION

[0042] To address the existing problems of polymer solid electrolyte membranes requiring solvents and initiators during processing and forming, resulting in low ionic conductivity, the present invention provides a method for preparing an all-solid-state polymer electrolyte using liquid, solvent-free in-situ thermal crosslinking. By employing a liquid, thermally crosslinkable material, such as poly(styrene-isobutylene-styrene) triblock polymer (xSIBS), the method eliminates the need for solvents and initiators. Furthermore, by regulating the ratio of soft and hard segments, the microphase separation effect is further enhanced, providing ion channels and thus further improving the ionic conductivity of the electrolyte membrane.

[0043] The present invention also provides a solid electrolyte membrane. The membrane's preparation process does not involve the introduction of solvents or initiators, thus avoiding the problem of pores in the membrane during solvent volatilization. Furthermore, the membrane is a liquid material at room temperature. After high-temperature cross-linking and in-situ curing, the electrolyte is prepared in an integrated manner, reducing costs. Furthermore, the polymer is used not only as a binder, but also as a base for further improving the ionic conductivity of the polymer.

[0044] The specific implementation methods of the present invention are further described below in conjunction with examples, but the present invention is not limited to the scope of the examples.

[0045] Example 1

[0046] Preparation of liquid thermally cross-linkable poly(styrene-b-isobutylene-b-styrene) triblock polymer (xSIBS): After baking and evacuating the glassware to remove water and oxygen, the glassware was fixed in a glove box equipped with a low-temperature cold trap under a nitrogen atmosphere. After cooling to -80°C, 580 ml of methylcyclohexane, 200 ml of chloromethane, 2 g of the main initiator 5-tert-butyl-1,3-di(methylethylchloro)benzene (purchased from outside, CAS number 89700-88-9), 0.21 g of 2,6-di-tert-butylpyridine, 8.5 g of the first monomer of the first part, isobutylene, and 12.5 g of the co-initiator titanium tetrachloride were added in sequence; after polymerization for 20 minutes, 85.4 g of the second monomer of the first part, isobutylene, was added. After polymerization was continued for 90 minutes, a mixture of 55 ml of the second monomer styrene and 6.4 ml of 4-vinylbenzocyclobutene dissolved in 350 ml of methylcyclohexane was added. After polymerization for 25 minutes, 50 ml of methanol was added to terminate the reaction to obtain xSIBS.

[0047] By further controlling the ratio of the first monomer, isobutylene, to the second monomer, styrene, the mass fraction of the polystyrene segments in the final product can be controlled, thereby preparing triblock polymers with varying microphase separation tendencies. In the present examples, xSIBS with polystyrene mass fractions of 10%, 30%, and 40% (referring to the mass content of styrene in the xSIBS) were selected, and the resulting polymer samples were designated xSIBS-10, xSIBS-30, and xSIBS-40, respectively.

[0048] Example 2

[0049] Preparation of liquid thermally cross-linkable poly(styrene-b-isobutylene-b-styrene) triblock polymer (xSIBS) solid electrolyte membrane:

[0050] Solid electrolyte precursors were prepared by mixing the xSIBS-10, xSIBS-30, and xSIBS-40 polymers prepared in Example 1 as raw materials, lithium perchlorate as an inorganic conductive filler, and a polymer to conductive filler mass ratio of 50:50. The solid electrolyte precursors were coated on a polytetrafluoroethylene-based substrate using a scraper; the scraper ruler thickness was preferably 500 to 900 μm. The coated substrate was placed in a vacuum oven and heated to 250°C for 50 minutes for thermal crosslinking to obtain solid electrolyte membranes, designated xSIBS-10M, xSIBS-30M, and xSIBS-40M, respectively.

[0051] The ionic conductivity of the three solid electrolytes mentioned above was tested respectively, and the results are shown in Table 1. The degree of microphase separation was observed by transmission electron microscopy, and the results are shown in Table 1. Figure 1 As shown, Figure 1 From left to right: xSIBS-10M, xSIBS-30M, and xSIBS-40M. Test results show that increasing the polystyrene segment ratio improves phase separation. However, as the polystyrene segment ratio increases, the ionic conductivity initially increases and then decreases. This may be because increasing the polystyrene segment ratio also increases the degree of crosslinking, which affects ion mobility. The ion transfer number results also confirm this hypothesis. Therefore, the optimal polystyrene segment ratio and degree of crosslinking can be selected by adjusting the segment ratio to achieve the highest ionic conductivity and ion transfer number.

[0052] Table 1 Test results of electrochemical and physical properties of the solid electrolyte membrane obtained in Example 2

[0053]

[0054] Example 3

[0055] Preparation of batteries with liquid thermally cross-linkable poly(styrene-isobutylene-styrene) triblock polymer (xSIBS) solid electrolyte membrane:

[0056] The xSIBS-10, xSIBS-30 and xSIBS-40 polymers prepared in Example 1 were used as raw materials, and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) was used as an inorganic conductive filler. The xSIBS and LiTFSI were uniformly mixed by high-speed stirring in a mass ratio of 40:60 to prepare a solid electrolyte precursor slurry.

[0057] Lithium iron phosphate is used as the positive electrode material, graphite is used as the positive electrode conductive additive, and polyvinylidene fluoride (PVDF) is used as the binder. They are dissolved in NMP solvent at a mass ratio of 7.5:1.5:1. After being fully ground to mix evenly, the slurry is coated on aluminum foil and completely dried, and then sliced ​​to obtain the positive electrode sheet.

[0058] The above-mentioned electrode sheet is used as the positive electrode in the solid-state battery and metallic lithium is used as the negative electrode. The obtained composite solid electrolyte slurry is dripped onto the surface of the positive electrode sheet and the negative electrode metallic lithium sheet respectively, and then pressurized and encapsulated in a button battery shell; the button battery is heated at 180°C for reaction to obtain xSIBS-10C, xSIBS-30C and xSIBS-40C all-solid-state lithium metal batteries.

[0059] The above-assembled all-solid-state battery was subjected to cycle and rate tests under high temperature conditions. Figure 2 This is the surface SEM morphology of the solid electrolyte membrane (xSIBS-30M) obtained in Example 3 of the present invention. It can be seen that the liquid cross-linkable polymer and the LiTFSI inorganic particles are tightly compounded and well dispersed.

[0060] Comparative Example 1

[0061] This comparative example differs from Example 3 in that an in-situ thermal crosslinking process is not used. Instead, the solid electrolyte membrane is prepared first (same as in Example 2) and then composited with the positive and negative electrodes. A solid electrolyte membrane with a 30% polystyrene segment ratio, designated xSIBS-30C', is used. All other conditions and parameters are identical to those in Example 3.

[0062] The lithium-ion batteries xSIBS-10C, xSIBS-30C, xSIBS-40C, and xSIBS-30C′ provided in Example 3 and Comparative Example 1 were subjected to battery performance and mechanical property tests, wherein the battery testing method is as follows: the all-solid-state lithium metal battery was subjected to constant current charge and discharge at 60°C and a current density of 0.2C within the range of 2.8-4.0V to test the initial discharge specific capacity, and the battery discharge specific capacity and capacity retention rate were tested after 100 cycles.

[0063] The test results are shown in Table 2. As can be seen, the electrochemical performance of the solid-state battery formed by in-situ cross-linking is superior to that of the comparative example formed in steps. Specifically, the maximum tensile strength is affected by the degree of cross-linking, and the maximum tensile strength is lowest in the solid-state battery formed by first forming the solid electrolyte and then composited. This indicates that the in-situ integration of the liquid cross-linkable xSIBS polymer with the positive and negative electrodes can improve the overall mechanical strength of the composite solid-state battery, help inhibit the growth of lithium dendrites, and improve capacity retention.

[0064] Table 2 Electrochemical and physical performance test results of solid-state batteries obtained in Example 3 and Comparative Example 1

[0065]

[0066] The embodiments and comparative examples of the present invention involve performance testing methods:

[0067] 1. Determination of ionic conductivity

[0068] The solid electrolyte membrane formed by solidification was cut into membranes with a diameter of 1.2 cm, and then placed between two steel sheets. The resistance at different temperatures was tested by AC impedance using an electrochemical workstation, and the ionic conductivity of the membrane at different temperatures was calculated using formula (1);

[0069] σ=t / R×S(1)

[0070] Where, σ is the ionic conductivity (S / cm), t is the thickness of the electrolyte membrane (cm), R is the in-plane resistance perpendicular to the membrane surface (Ω), and S is the effective membrane area (cm 2 ).

[0071] 2. Ion migration number

[0072] The solid electrolyte membrane formed by solidification alone was cut into a membrane with a diameter of 1.2 cm, and then placed between two lithium sheets to make a buckle, and then the EIS and DC were tested, and then calculated using the following formula.

[0073]

[0074] In formula (2), ΔV is the polarization voltage, Io and Is are the initial current and stable current obtained from the DC polarization test, respectively, Rf and Ri are the bulk resistance of the polymer electrolyte before and after the DC polarization test, respectively, and Ro and Rs are the interface resistance before and after the DC polarization test, respectively.

[0075] 3. Elastic tensile test

[0076] The solid electrolyte membrane, formed by solidification, was cut into 1 x 5 cm rectangles. It was placed in the fixture of a LY-1065B computerized tensile testing machine and stretched at a speed of 20 mm / min until it broke. Before breaking, a yield point—the point where stress increase and strain are minimal—appeared. The elastic deformation region satisfies Hooke's law, meaning that stress and strain are linearly related. The stress and strain at this point are the elastic stress and elastic strain ΔL, respectively.

[0077] 4. Room temperature rate performance

[0078] The solid-state battery was charged and discharged at 25°C using a battery charge and discharge tester. The charge and discharge regime was as follows: 0.2C constant current charging to 4.4V, then switching to 4.4V constant voltage charging until the current decreased to 0.02C. After standing for 5 minutes, the battery was discharged at a constant current of 0.2C to 2.75V, and the discharge capacity Q0.2C was recorded. After standing for 5 minutes, the battery was charged at a constant current of 0.2C to 4.4V, then switched to 4.4V constant voltage charging until the current decreased to 0.02C. After standing for 5 minutes, the battery was discharged at a constant current of 3C to 2.75V, and the discharge capacity Q3C was recorded. The 3C discharge capacity retention rate η = Q3C / Q0.2C×100%.

[0079] The various embodiments in this specification are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from the other embodiments. In particular, the description of polymer synthesis is relatively simple, as it is fundamentally similar to the method embodiments. For relevant details, refer to the partial descriptions of the method embodiments and the cited patents. The device and system embodiments described above are merely illustrative.

[0080] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing an all-solid-state battery, characterized in that: The preparation method comprises the following steps: first preparing an electrolyte precursor slurry, coating the obtained precursor slurry on the surfaces of a positive electrode sheet and a negative electrode sheet, then encapsulating the resulting slurry in a battery shell, and finally heating the battery at 150 to 350° C. for 2 minutes to 24 hours for cross-linking to obtain an all-solid-state battery; wherein the raw materials of the electrolyte precursor slurry include a polymer and a lithium salt, and the polymer is a polymer that is liquid at room temperature and has a heat-crosslinkable structure in its molecular chain.

2. The method for preparing an all-solid-state battery according to claim 1, wherein: The mass ratio of the polymer to the lithium salt is (1-99):(99-1).

3. The method for preparing an all-solid-state battery according to claim 1 or 2, characterized in that: The polymer is a copolymer having a plurality of structural units, wherein the structural units include a first structural unit, a second structural unit and a third structural unit, wherein the first structural unit is derived from at least one cationically polymerizable branched olefin monomer, wherein the branched olefin monomer is selected from the group consisting of isobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene and combinations thereof; The second structural unit is derived from at least one cationic polymerizable olefin monomer having a benzocyclobutene side group; the third structural unit is a monomer capable of forming a glass segment, selected from styrene, indene, α-methylstyrene, 4-tert-butylstyrene or a combination thereof.

4. The method for preparing an all-solid-state battery according to claim 3, characterized in that: The first structural unit monomer is isobutylene; The second structural unit monomer is 4-vinylbenzocyclobutene; The third structural unit monomer is styrene.

5. The method for preparing an all-solid-state battery according to claim 4, characterized in that: The polymer is prepared by the following method: first, pre-cooling a mixed solvent at -60 to -100°C, then sequentially adding a main initiator, a proton scavenger, a first part of the first monomer, isobutylene, and a co-initiator, polymerizing for 10 to 30 minutes, then adding a second part of the first monomer, isobutylene, continuing the polymerization for 50 to 120 minutes, then adding a mixture of a second monomer, styrene, and a cross-linking agent dissolved in solvent 1, and polymerizing for 10 to 50 minutes before terminating the reaction; the mass ratio of the first part of the first monomer to the second part of the first monomer is: (1 to 20): (80 to 99%).

6. The method for preparing an all-solid-state battery according to claim 5, characterized in that: The ratio of each raw material is as follows: the molar ratio of the second monomer to the first monomer is 1:(5-40), the molar ratio of the crosslinking agent to the first monomer is (1-20):(80-99), the concentration of the main initiator is 0.001-1 mol / L, the molar ratio of the proton scavenger to the main initiator is (1-5):1; the molar ratio of the main initiator to the co-initiator is 1:(16-64); the molar concentration of the first monomer is 1-10 mol / L; the volume ratio of the solvent 1 to the second monomer is (2-6):1; The main initiator is 5-tert-butyl-1,3-di(methylethylchloro)benzene; Furthermore, the co-initiator is at least one selected from titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkyl aluminum chloride; Furthermore, the mixed solvent is a co-solvent of solvent 1 and solvent 2, wherein solvent 1 is selected from at least one of cyclohexane, n-hexane, and methylcyclohexane; and solvent 2 is selected from at least one of chloromethane, dichloromethane, and chloroform. Further, the cross-linking agent is selected from: 4-vinylbenzocyclobutene; The proton scavenger is a tertiary amine compound, such as a substituted or pentasubstituted aromatic tertiary amine compound, preferably at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine or 2,4,6-tri-tert-butylpyridine.

7. The method for preparing an all-solid-state battery according to any one of claims 1 to 6, characterized in that: The lithium salt is selected from the group consisting of lithium perchlorate, lithium bis(fluorosulfonyl imide), lithium bis(trifluoromethanesulfonyl imide), lithium hexafluorophosphate, lithium hexafluorophosphate type sulfide solid electrolyte, LGPS type sulfide solid electrolyte, and argon sulfide type solid electrolyte, or a combination of at least two thereof; preferably lithium bis(trifluoromethanesulfonyl imide); Furthermore, the electrolyte precursor slurry is prepared by the following method: the polymer and lithium salt are mixed uniformly at 10-99° C. to prepare the precursor slurry.

8. An all-solid-state battery, characterized in that: The invention discloses a novel novel nanostructured carbonyl phosphate ...

9. A solid electrolyte membrane, characterized in that The electrolyte membrane is formed by coating an electrolyte precursor slurry on a substrate membrane and then heating and cross-linking to obtain the solid electrolyte membrane; wherein the electrolyte precursor slurry is prepared by the following method: the modified liquid cross-linkable polymer according to any one of claims 1 to 7 and a lithium salt are uniformly mixed at 10 to 99° C. to obtain the precursor slurry; Furthermore, the base film material is selected from: polytetrafluoroethylene or polyimide; Furthermore, the cross-linking temperature is 150 to 350°C; Furthermore, the heating cross-linking time is 2 minutes to 24 hours.

10. Use of a polymer that is liquid at room temperature and has a thermally crosslinkable structure in its molecular chain in the preparation of an all-solid-state battery electrolyte, wherein the polymer is liquid at room temperature and has a thermally crosslinkable structure in its molecular chain; Furthermore, a method for using a polymer that is liquid at room temperature and has a heat-crosslinkable structure in its molecular chain in preparing an all-solid-state battery electrolyte is as follows: first preparing an electrolyte precursor slurry, then coating the obtained precursor slurry on the surface of the positive electrode sheet and the negative electrode sheet, then encapsulating it in a battery shell, and finally heating it at 150 to 350° C. for 2 minutes to 24 hours to crosslink it to prepare an all-solid-state battery; wherein, The electrolyte precursor slurry is prepared by the following method: the polymer and lithium salt are mixed uniformly at 10-99° C. to prepare the precursor slurry; Furthermore, the polymer is a copolymer having multiple structural units, wherein the structural units include first, second and third structural units, wherein the first structural unit is derived from at least one cationically polymerizable branched olefin monomer, wherein the branched olefin monomer is selected from isobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene and combinations thereof; The second structural unit is derived from at least one cationic polymerizable olefin monomer having a benzocyclobutene pendant group; the third structural unit is a monomer capable of forming a glass segment, selected from the group consisting of styrene, indene, α-methylstyrene, tert-butylstyrene, or a combination thereof; Furthermore, the first structural unit monomer is isobutylene; the second structural unit monomer is 4-vinylbenzocyclobutene; and the third structural unit monomer is styrene.

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