Preparation method of in-situ polymerization solid-state battery

Abstract

The invention discloses a preparation method of an in-situ polymerization solid-state battery, which comprises the following steps: uniformly mixing a flame-retardant additive, a polymer monomer, an initiator and a lithium-containing electrolyte to prepare a precursor liquid, injecting the precursor liquid, carrying out formation after vacuum standing and sufficient aging accelerated infiltration, vacuumizing after formation, and then carrying out hot-pressing curing. In the process, only one-time liquid injection is needed, vacuumizing and standing are carried out in a vacuum oven at the temperature of 10-30 DEG C to promote the precursor liquid to uniformly permeate into the battery cell, and standing is carried out at the temperature of 25-45 DEG C to fully age, so that the precursor liquid is further promoted to uniformly infiltrate the electrode material; the introduction of the flame retardant further improves the safety of the system; in addition, since the semi-solid battery developed by using the in-situ solidification technology can use similar production equipment to current commercial batteries, large-scale application is facilitated. Compared with a non-in-situ curing process, the in-situ curing process disclosed by the invention is better in interfacial compatibility, and the safety and the electrochemical performance of the battery can be better improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and in particular relates to a method for preparing an in-situ polymerization solid-state battery. Background Art

[0002] The organic liquid electrolyte of traditional lithium-ion batteries is flammable and explosive at high temperatures, causing thermal runaway of the battery and posing a major safety hazard; solid-state lithium batteries using non-flammable solid electrolytes can effectively solve the above problems. Among the commonly used solid electrolytes, organic polymer solid electrolytes have simple preparation methods, better ductility, stronger flexibility, good film-forming properties, and good electrode-electrolyte interface contact, but their poor mechanical properties and low ionic conductivity at room temperature limit their commercial applications. Inorganic solid electrolytes have high room temperature ionic conductivity, but they have poor flexibility, poor interface compatibility, complex preparation processes, and high costs, which also limit their commercial applications. In-situ polymerization is compatible with existing liquid battery processes, but is prone to uneven polymerization. Polymer monomers, lithium salts and initiator compounds are injected into the battery, and the electrolyte is solidified into a solid by high-temperature heating. Using this method, since the monomers, lithium salts, cross-linking agents and initiator compounds cannot be evenly dispersed in the battery, this leads to uneven in-situ polymerization reactions and thus uneven solid electrolyte interfaces. The batteries produced in this way have poor consistency and poor electrochemical performance. The batteries produced by this method have high internal resistance, which reduces the charge and discharge efficiency in the first week. In addition, problems such as high-temperature thermal runaway cannot be avoided.

[0003] The patent document with the announcement number CN114335716A discloses an in-situ polymerization solid-state battery with a multilayer electrolyte structure and a preparation method thereof, wherein the electrolyte is injected into the battery cell to initiate monomer polymerization to form a multilayer electrolyte structure; the electrolyte contains a first reaction monomer and a second reaction monomer, a first initiator, and a second initiator. The solid-state battery is obtained by direct heating and curing. This patent directly heats and cures after liquid injection, which is prone to uneven curing, and the formation after curing is not conducive to the formation of SEI film.

[0004] The patent document with the announcement number CN117276686A discloses a preparation method of a solid-state battery based on cationic in-situ polymerization. The in-situ polymerization liquid in the patent includes an initiator and a dehydrating polymerization monomer solvent, a Lewis acid lithium salt and a film-forming additive; the in-situ polymerization liquid is injected into a solid-state battery cell that has not undergone cationic in-situ polymerization, and cationic polymerization is carried out at room temperature. After standing for 2 to 10 hours, a solid-state battery based on cationic in-situ polymerization is obtained. The in-situ polymerization liquid is injected into a supporting diaphragm, the diaphragm is pre-polymerized, and cationic polymerization is carried out at room temperature. After standing, a pre-polymerized diaphragm is obtained, but this method will result in uneven polymerization; and the in-situ polymerization liquid and the specific curing process of the patent are different from those of the present application.

[0005] In this application, a precursor solution is prepared by uniformly mixing a flame retardant additive, polymer monomers, an initiator, and a lithium-containing electrolyte. After injecting the electrolyte, vacuum standing and sufficient aging are carried out to accelerate infiltration, followed by formation. After formation, vacuum is pumped, and then hot pressing and curing are carried out. Among them, the polymer precursor solution is different from the above patent. Adding a flame retardant and a lithium-containing electrolyte is more beneficial to the electrical performance of the battery; the process method is different. The vacuum pumping process can help accelerate infiltration. After the pressure formation is completed, vacuum is pumped, pressure is applied for high-temperature curing, vacuum is pumped again after curing, and then packaging is carried out to obtain a solid-state battery. Forming first and then curing is beneficial to the formation of a stable SEI film, and this process is beneficial to the uniform curing of the battery. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for preparing an in-situ polymerization solid-state battery.

[0007] The present invention is achieved through the following technical solutions.

[0008] A method for preparing an in-situ polymerization solid-state battery provided by the present invention includes the following steps:

[0009] S1: Mix an electrolyte, a flame retardant additive, a first polymer monomer, a second polymer monomer, and an initiator uniformly to obtain a precursor solution;

[0010] S2: Inject the precursor solution into the battery. After heating the battery, vacuum is pumped, the pressure is released after standing, and then standing aging infiltration is carried out. Then, the formation process of the battery is carried out by using a clamping plate;

[0011] S3: After the formation is completed, vacuum is pumped at room temperature, the pressure is released after standing, and then the first vacuum heat sealing is carried out;

[0012] S4: After vacuum pumping, the battery is clamped by a clamping plate, and then heating and curing are carried out. After the curing is completed, the second vacuum heat sealing is carried out. The edge of the battery is heat sealed by a sealing machine. After cutting, the preparation of the in-situ polymerization solid-state battery is completed.

[0013] Preferably, the battery includes a stacked or wound soft-pack battery. The battery includes a positive electrode, a negative electrode, and a separator. Among them, the separator includes one of a high-porosity polyethylene-based membrane, a ceramic separator, an LATP electrolyte membrane, a non-woven fabric separator, and an electrospun separator; the positive electrode material includes any one or a mixture of high-voltage lithium cobaltate, high-nickel ternary materials, and lithium-rich manganese-based materials; the negative electrode material includes a lithium metal or a lithium alloy negative electrode.

[0014] Preferably, the electrolyte includes a lithium salt and an organic solvent. The organic solvent includes one or more of dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether;

[0015] The lithium salt includes one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(oxalato)borate;

[0016] The concentration of the lithium salt in the electrolyte is 1 to 1.3 mol / L;

[0017] The content of the electrolyte is 20% to 75% of the total weight of the precursor solution.

[0018] Preferably, the flame retardant includes one or more of trimethyl phosphate, triethyl phosphate, tributyl phosphate, and bis(trifluoroethyl)methyl phosphate, and the content of the flame retardant is 5% to 30% of the total weight of the precursor solution.

[0019] Preferably, the first polymer monomer includes at least one of vinylene carbonate, vinyl acetate, dimethyl allyl malonate, diethyl allyl malonate, methyl allyl carbonate, methyl methacrylate, and butyl methacrylate, and the content of the first polymer monomer is 10% to 30% of the total weight of the precursor solution.

[0020] Preferably, the second polymer monomer includes at least one of polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, ethoxyethyl acrylate, polyethylene glycol, and polyethylene glycol dialkylacrylate, and the content of the second polymer monomer is 5% to 30% of the total weight of the precursor solution.

[0021] Preferably, the initiator includes at least one of azobisisobutyronitrile, benzoyl peroxide, azobisisoheptonitrile, dimethyl azobisisobutyrate, and tert-butyl benzoyl peroxide, and the content of the initiator is 1% to 10% of the total weight of the precursor solution.

[0022] Preferably, the degree of vacuum of the vacuum oven used in steps S2, S3, and S4 ≤

[0023] -0.085 MPa; the sealing temperature of the vacuum sealer used for the first vacuum heat sealing and the second vacuum heat sealing is 185 to 190 °C, and the degree of vacuum ≤ -0.087 MPa; the temperature of the sealer in S4 is 185 to 190 °C;

[0024] In the operations of evacuating, standing still, and then releasing pressure at room temperature in steps S2 and S3, the standing time ≥ 5 min, and in the preparation of the in-situ polymerization solid-state battery, the number of operations of evacuating, standing still, and then releasing pressure ≥ 2 times.

[0025] Preferably, the injection volume of the precursor solution is 1.5 to 3 g / Ah, the aging temperature is in the range of 30 to 45 °C, and the battery aging time is 10 to 24 h;

[0026] In the formation process in step S2, pressure application formation is carried out, with a pressure of 100 - 220 kg applied, and the formation rate is charge and discharge at 0.05C - 0.2C.

[0027] Preferably, the vacuum degree of the first vacuum heat sealing and the second vacuum heat sealing ≤ -0.087 MPa;

[0028] In step S4, during the curing process, the pressure applied by the clamping plate is 1000 - 2500 N, the temperature is 50 - 80 °C; the curing time ≥ 24 h.

[0029] The beneficial effects of the present invention are as follows:

[0030] Compared with the non-in-situ curing process, the in-situ curing process of the present invention has better interfacial compatibility and can better improve the battery safety and electrochemical performance. In addition, for the in-situ polymerization solid-state battery prepared by the present invention, through vacuum static placement and sufficient aging static placement, the precursor solution is fully infiltrated. After pressure application formation, vacuum is pumped, heat curing is carried out, and then vacuum is pumped again to effectively discharge the side reaction gases; the effect of vacuum pumping and using the clamping plate to apply pressure for curing is good, which can effectively improve the interfacial impedance compared with direct curing. This process effectively solves the problems of uneven polymerization and poor battery electrical performance during the in-situ polymerization process. In addition, the introduction of the flame retardant additive can effectively alleviate the problem of high-temperature thermal runaway. The battery has good interfacial contact between the electrolyte and the battery electrode and excellent charge and discharge cycle performance. The present invention takes into account the existing lithium battery process equipment, the preparation method is simple, and the prepared solid-state battery has excellent performance, which is conducive to large-scale production. Description of the Drawings

[0031] Figure 1 is the first-week charge and discharge curve diagram after in-situ curing of the solid-state battery prepared in Example 1 of the present invention;

[0032] Figure 2 is the cycle performance diagram of the solid-state battery prepared in Example 1 of the present invention. Detailed Embodiments

[0033] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited thereto.

[0034] Example 1:

[0035] A preparation method of an in-situ polymerization solid-state battery, comprising the following steps:

[0036] S1: Mix the electrolyte (1.2 mol / L LITFSI in the electrolyte (DME:TTE volume ratio = 1:5)), the flame retardant additive, the first polymer monomer, the second polymer monomer, and the initiator evenly according to the mass ratio of 69:15:1:10:5 to obtain a precursor solution;

[0037] S2: Inject the precursor solution into the LCO lithium metal laminated soft-pack battery. Place the open battery in a vacuum oven, evacuate it at room temperature, let it stand, then release the pressure. Seal the battery, and then let it stand and age to fully infiltrate. Then, perform the formation process on the battery using a clamping plate.

[0038] S3: After the formation is completed, place the open battery in a vacuum oven again, evacuate it, let it stand, and then release the pressure. Thereafter, perform the first vacuum heat sealing.

[0039] S4: After evacuation, clamp the battery using a clamping plate, then place it in an oven for heating and curing. After the curing is completed, perform the second vacuum heat sealing. Seal the edge of the battery with a sealing machine, and cut off the excess aluminum-plastic film. After cutting, the preparation of the in-situ polymerization solid-state battery is completed.

[0040] The battery includes a laminated or wound soft-pack battery, and the battery includes a positive electrode, a negative electrode, and a separator. The separator includes a high-porosity polyethylene (PE) film with a thickness of 15 μm; the positive electrode material is high-voltage lithium cobaltate; the negative electrode material is lithium metal.

[0041] The electrolyte includes a lithium salt and an organic solvent, and the organic solvent includes dimethyl ether and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE);

[0042] The lithium salt is lithium hexafluorophosphate (LiPF6);

[0043] The flame retardant is trimethyl phosphate.

[0044] The first polymer monomer is vinylene carbonate.

[0045] The second polymer monomer is polyethylene glycol dimethacrylate.

[0046] The initiator is azobisisobutyronitrile (AIBN).

[0047] In steps S2, S3, and S4, heating is performed using a vacuum oven. The temperature of the vacuum oven is set at 25 °C, and the vacuum degree is -0.085 MPa;

[0048] In the operations of evacuating, standing, and then releasing the pressure at room temperature in steps S2 and S3, the standing time is 5 min. In the preparation of the in-situ polymerization solid-state battery, the number of operations of evacuating, standing, and then releasing the pressure is 2 times.

[0049] The injection volume of the precursor solution is 2.5 g / Ah, the aging temperature ranges from 40 °C, and the battery aging time is 20 h;

[0050] In step S2, the formation process is pressure formation, the applied pressure is 160 kg, and the formation rate is 0.1C charge and discharge.

[0051] The degree of vacuum for the first vacuum pumping is -0.087 MPa, and the degree of vacuum for the second vacuum pumping is -0.089 MPa;

[0052] In step S4, the pressure applied by the clamping plate during the curing process is 2000 N, the temperature is 65 °C; the curing time is 26 h.

[0053] Under the conditions of room temperature, 3.0 - 4.45 V, 0.1 C charge / 0.5 C discharge, the electrochemical performance test is carried out. The specific energy of the battery is as high as 350 Wh / Kg, the capacity retention rate after 90 cycles is about 92.0%, and the charge-discharge curve in the first week after in-situ curing is shown in Figure 1 , and the cycle performance diagram of this solid-state battery is shown in Figure 2 .

[0054] Example 2:

[0055] A preparation method of an in-situ polymerization solid-state battery includes the following steps:

[0056] S1: Mix the electrolyte (1.1 mol / L lithium salt in the electrolyte (where the mass ratio of LiPF6: LITFSI = 1:2; the volume ratio of DME: TTE: FEC = 2:7:1)), the flame retardant additive, the first polymer monomer, the second polymer monomer, and the initiator evenly according to the mass ratio of 57:20:2:10:10 to obtain a precursor solution;

[0057] S2: Inject the precursor solution into the NCM laminated lithium metal soft-pack battery. The battery opening is placed in a vacuum oven, evacuated at room temperature, left standing, and then the pressure is released. The battery is sealed, and then left standing for aging to be fully infiltrated. Then, the formation process of the battery is carried out by using a clamping plate;

[0058] S3: After the formation is completed, the battery opening is placed in a vacuum oven, evacuated again at room temperature, left standing, and then the pressure is released. Thereafter, the first vacuum heat sealing is carried out;

[0059] S4: After vacuum pumping, the battery is clamped by a clamping plate, and then placed in an oven for heating and curing. After the curing is completed, the second vacuum heat sealing is carried out to complete the preparation of the in-situ polymerization solid-state battery.

[0060] The battery includes a laminated or wound soft-pack battery. The battery includes a positive electrode, a negative electrode, and a separator. The separator includes a ceramic separator with a thickness of 9 μm; the positive electrode material is a high-nickel ternary material; the negative electrode material is a lithium alloy negative electrode.

[0061] The electrolyte includes a lithium salt and an organic solvent. The organic solvent is dimethyl ether, fluoroethylene carbonate (FEC), and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE);

[0062] The lithium salt is lithium hexafluorophosphate (LiPF6) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI);

[0063] The flame retardant is triethyl phosphate.

[0064] The first polymer monomer is vinyl acetate, dimethyl allyl dicarboxylate, and methyl allyl carbonate.

[0065] The second polymer monomer is polyethylene glycol diacrylate and ethoxyethyl acrylate.

[0066] The initiator is benzoyl peroxide (BPO) and azobisisoheptonitrile (ABVN).

[0067] The vacuum degree of the vacuum oven in steps S2, S3, and S4 is -0.085 MPa;

[0068] In the operations of evacuating, standing, and then releasing pressure at room temperature in steps S2 and S3, the standing time is 5 min, and in the preparation of the in-situ polymerization solid-state battery, the number of operations of evacuating, standing, and then releasing pressure is 2 times.

[0069] The injection volume of the precursor solution is 1.5 g / Ah, the aging temperature ranges from 45 °C, and the battery aging time is 15 h;

[0070] In the formation process in step S2, pressure application formation is carried out, the applied pressure is 220 kg, and the formation rate is 0.2C charge and discharge.

[0071] The vacuum degree of the first evacuation and the second evacuation is -0.087 MPa;

[0072] In step S4, the pressure applied by the clamping plate during the curing process is 1500 N, the temperature is 50 - 80 °C; the curing time is ≥24 h.

[0073] At room temperature, under the conditions of 2.7 - 4.3 V and 0.2C charge and discharge, electrochemical performance tests are carried out. The specific energy of the battery is as high as 360 Wh / Kg, and the capacity retention rate after 100 cycles is about 87.5%.

[0074] Example 3:

[0075] A method for preparing an in-situ polymerization solid-state battery, comprising the following steps:

[0076] S1: Mix the electrolyte (1.2 mol / L LITFSI in the electrolyte, volume ratio of DME:TTE:FEC = 2:8:1), the flame retardant additive, the first polymer monomer, the second polymer monomer, and the initiator evenly according to a mass ratio of 48:25:2:10:15 to obtain a precursor solution;

[0077] S2: Inject the precursor solution into the battery. Place the open battery in a vacuum oven at room temperature, evacuate the air, let it stand, then release the pressure. Seal the battery, and then let it stand and age to achieve sufficient infiltration. Then, perform the formation process on the battery using a clamping plate.

[0078] S3: After the formation is completed, place the open battery in a vacuum oven at room temperature, evacuate the air again, let it stand, and then release the pressure. Thereafter, perform the first vacuum heat sealing.

[0079] S4: After evacuation, clamp the battery using a clamping plate, then place it in an oven for heating and curing. After the curing is completed, perform the second vacuum heat sealing to complete the preparation of the in-situ polymerization solid-state battery.

[0080] The battery includes a laminated or wound soft-pack battery, which includes a positive electrode, a negative electrode, and a separator. The separator includes a non-woven fabric separator with a thickness ≤ 14 μm; the positive electrode material is a high-nickel ternary material; the negative electrode material is a lithium alloy negative electrode.

[0081] The electrolyte includes a lithium salt and an organic solvent. The organic solvent is dimethyl ether, fluoroethylene carbonate (FEC), 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE);

[0082] The lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI);

[0083] The flame retardant includes bis(trifluoroethyl)methyl phosphate.

[0084] The first polymer monomer is methyl methacrylate and butyl methacrylate.

[0085] The second polymer monomer is polyethylene glycol and polyethylene glycol dialkyl acrylate.

[0086] The initiator is tert-butyl peroxybenzoate (TBPB).

[0087] The vacuum degree of the vacuum oven used in steps S2, S3, and S4 is -0.085 MPa;

[0088] In the operations of evacuating the air, letting it stand, and then releasing the pressure at room temperature in steps S2 and S3, the standing time is 5 min. In the preparation of the in-situ polymerization solid-state battery, the number of operations of evacuating the air, letting it stand, and then releasing the pressure is 2 times.

[0089] The injection volume of the precursor solution is 2.6 g / Ah, the aging temperature ranges from 30 °C, and the battery aging time is 21 h;

[0090] In step S2, the formation process is pressure formation, the applied pressure is 100 kg, and the formation rate is 0.1C / 0.2C charge and discharge.

[0091] The degree of vacuum for the first evacuation is -0.087 MPa, and the degree of vacuum for the second evacuation is -0.089 MPa;

[0092] In step S4, the pressure applied by the clamping plate during the curing process is 1000 N, the temperature is 50 °C, and the curing time is 24 h.

[0093] Under the conditions of room temperature, 3.0 - 4.45 V, 0.2C charge / 0.5C discharge, the electrochemical performance is tested. The specific energy of the battery is as high as 340 Wh / Kg, and the capacity retention rate after 70 cycles is about 86.1%.

[0094] Comparative Example 1:

[0095] The preparation method of an in-situ polymerization solid-state battery is basically the same as that of Example 1, except that the flame retardant is not added.

[0096] Under the conditions of room temperature, 3 - 4.4 V, 0.1C charge / 0.5C discharge, the electrochemical performance is tested. The specific energy of the battery is 350 Wh / Kg, the capacity retention rate after 90 cycles is about 93.5%, the self-ignition time (SET) of the in-situ polymerization liquid is ≥25 s, while the self-ignition time (SET) of Example 1 is ≤15 s. Adding a flame retardant can effectively improve safety.

Claims

1. A method for preparing an in-situ polymerization solid-state battery, characterized in that: The following steps are involved: S1: mixing an electrolyte, a flame retardant additive, a first polymer monomer, a second polymer monomer, and an initiator to obtain a precursor solution; S2: injecting the precursor solution into the battery, evacuating the battery at room temperature, releasing the pressure after standing, and then standing for aging and infiltration, and then performing the battery formation process by using a splint; S3: After the formation is completed, the battery is vacuumed again at room temperature, left to stand and then depressurized, and then the first vacuum heat sealing is performed; S4: After vacuuming, use a splint to clamp the battery, and then heat and cure it. After curing, perform a second vacuuming and heat sealing. The sealing machine heat seals the edge of the battery. After cutting, the preparation of the in-situ polymerization solid-state battery is completed.

2. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The battery includes a laminated or wound soft-pack battery, and the battery includes a positive electrode, a negative electrode, and a diaphragm, wherein the diaphragm includes one of a high-porosity polyethylene-based film, a ceramic diaphragm, a LATP electrolyte membrane, a non-woven fabric diaphragm, and an electrospinning diaphragm; the positive electrode material includes any one or more mixtures of high-voltage lithium cobalt oxide, high-nickel ternary materials, and lithium-rich manganese-based materials; the negative electrode material includes a lithium metal or lithium alloy negative electrode.

3. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The electrolyte includes a lithium salt and an organic solvent, and the organic solvent includes one or more of dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether; The lithium salt includes one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(oxalatoborate); The concentration of the lithium salt in the electrolyte is 1 to 1.3 mol / L; The content of the electrolyte is 20% to 75% of the total weight of the precursor solution.

4. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The flame retardant includes one or more of trimethyl phosphate, triethyl phosphate, tributyl phosphate, and bistrifluoroethyl methyl phosphate, and the content of the flame retardant is 5% to 30% of the total weight of the precursor solution.

5. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The first polymer monomer includes at least one of vinylene carbonate, vinyl acetate, dimethyl allyl dicarboxylate, diethyl allyl malonate, methallyl carbonate, methyl methacrylate, and butyl methacrylate, and the content of the first polymer monomer is 10% to 30% of the total weight of the precursor solution.

6. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The second polymer monomer includes at least one of polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, ethoxyethyl acrylate, polyethylene glycol, and polyethylene glycol dialkyl olefinic acid ester, and the content of the second polymer monomer is 5% to 30% of the total weight of the precursor solution.

7. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The initiator comprises at least one of azobisisobutyronitrile, benzoyl peroxide, azobisisoheptanenitrile, dimethyl azobisisobutyrate and tert-butyl benzoyl peroxide, and the content of the initiator is 1% to 10% of the total weight of the precursor solution.

8. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The vacuum degree of the vacuum oven used in the steps S2, S3 and S4 is ≤-0.085MPa; the sealing temperature of the vacuum sealer used in the first vacuum heat sealing and the second vacuum heat sealing is 185-190°C, and the vacuum degree is ≤-0.087MPa; the temperature of the S4 sealer is 185-190°C. In the operations of evacuating the vacuum and releasing the pressure after standing still in the steps S2 and S3, the standing still time is ≥5 min, and in the preparation of the in-situ polymerization solid-state battery, the number of operations of evacuating the vacuum and releasing the pressure after standing still is ≥2 times.

9. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The injection volume of the precursor solution is 1.5 to 3 g / Ah, the aging temperature is in the range of 30 to 45° C., and the battery aging time is 10 to 24 hours; The formation process in step S2 is pressure formation, the applied pressure is 100-220 kg, and the formation rate is 0.05C-0.2C charge and discharge.

10. The method for preparing an in-situ polymerization solid-state battery according to claim 1, characterized in that: The vacuum degree of the first vacuum heat seal and the second vacuum heat seal is ≤-0.087MPa; In step S4, during the curing process, the pressure applied by the clamp is 1000-2500N, the temperature is 50-80°C, and the curing time is ≥24h.

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