In-situ polymerized polymer solid-state battery and preparation method thereof

Abstract

The invention discloses an in-situ polymerized polymer solid-state battery, which is prepared by sequentially laminating and assembling a positive electrode / positive electrode side solid-state electrolyte, a basement membrane B coated with an electrolyte precursor solution B and a negative electrode sheet into a battery structure, and standing for 1-48 hours in an environment of 10-50 DEG C to generate an in-situ ring-opening polymerization reaction. The preparation method comprises the following steps: fully infiltrating pores of a basement membrane with an electrolyte precursor solution by adopting an in-situ polymerization technology, and then initiating a polymerization reaction in the electrolyte precursor solution to form a continuous interface double-layer solid electrolyte so as to obtain an integrated polymer solid-state battery, so that the problem of solid-solid interface contact of a traditional solid-state battery is solved; molecular-level tight combination between the electrode and the electrolyte is achieved, and interface impedance is remarkably reduced.

Description

Technical Field

[0001] This invention belongs to the field of lithium metal battery technology, and specifically relates to an in-situ polymer solid-state battery and its preparation method. Background Technology

[0002] With the increasing demand for high-energy-density and high-safety batteries from electric vehicles, large-scale energy storage, and portable electronic devices, the development of traditional lithium-ion batteries is facing bottlenecks. The organic liquid electrolytes they use have inherent safety hazards such as easy leakage, flammability, and explosiveness, and their energy density (currently generally below 300 Wh / kg), charging rate, and operating temperature range are gradually approaching their theoretical limits.

[0003] Solid-state batteries (SSBs) are considered a strategic direction for the next generation of energy storage technology. The core of this technology lies in the complete replacement of traditional liquid electrolytes and separators with solid-state electrolytes (SSEs). This change brings multiple theoretical advantages: (1) It completely eliminates the leakage and combustion risks of liquid electrolytes and is resistant to high temperatures, punctures and short-circuit impacts; (2) It allows the use of lithium metal anodes (theoretical specific capacity up to 3860 mAh / g) and can be matched with high-voltage cathode materials (such as lithium-rich manganese-based, nickel-manganese spinel, etc.), which is expected to enable the energy density of single cells to exceed 500 Wh / kg; (3) The solid-state system can effectively suppress lithium dendrites and electrode structure degradation and extend cycle life; (4) It is expected to work stably in extreme environments from -50℃ to 120℃.

[0004] Despite its promising prospects, solid-state batteries still face three major challenges in moving from the laboratory to large-scale commercialization. Currently, all mainstream solid-state electrolyte materials have inherent defects, and there is no "perfect" material yet: (1) Inorganic solid-state electrolytes: mainly including oxides (such as LLZO, LLTO) and sulfides (such as LPS, LPSCl); (2) Oxide electrolytes: have good chemical stability and high mechanical strength, but are brittle and hard, making them difficult to process into dense films, resulting in poor rigid contact with electrodes, and generally low room temperature ionic conductivity; (3) Sulfide electrolytes: have the highest room temperature ionic conductivity (up to 10). - ³~10 - ² S / cm, close to liquid electrolyte), but with extremely poor chemical stability, it reacts with water vapor in the air to produce highly toxic H2S gas, and has extremely stringent requirements for the production environment (dry room / glove box) and packaging technology, resulting in high cost; (4) Polymer solid electrolyte: represented by polyethylene oxide (PEO), it has good flexibility and processability, and low cost. However, its fatal weakness is its low room temperature ionic conductivity (usually <10 S / cm). -5The S / cm ratio depends on operating at high temperatures of 60-80°C, which severely limits its application scenarios.

[0005] Solid-solid interface contact and stability are the most critical obstacles restricting the performance of solid-state batteries. Liquid electrolytes can flow and form perfect liquid-solid contacts with electrode particles, while solid electrolytes and electrodes have solid-solid contacts with small physical contact areas and high interfacial impedance. Electrodes (especially the positive electrode) are porous composites composed of active materials, conductive agents, and binders. Solid electrolytes cannot penetrate into the pores like liquids, resulting in a small effective contact area, limited ion transport channels, and a sharp increase in internal resistance and capacity decay. Under high voltage, the positive electrode material and solid electrolyte may undergo chemical / electrochemical side reactions, generating a high-resistance interfacial layer, further increasing ion transport resistance. During cycling, lithium ions are unevenly deposited on the negative electrode surface, forming lithium dendrites. The mechanical strength of some solid electrolytes (especially softer polymers and sulfides) is insufficient to consistently suppress dendrite growth, which may cause dendrites to penetrate the electrolyte, resulting in internal short circuits.

[0006] The high cost is a major obstacle to the commercialization of solid-state batteries. This is mainly because solid electrolyte materials (such as lithium sulfide and rare metals) are expensive. To improve the solid-solid interface, complex processes such as high-temperature sintering (oxides), cold / hot isostatic pressing, or the fabrication of ultra-thin electrolyte membranes are often required, which are technically challenging and have low yields. In particular, the sulfide route requires the entire production line to be carried out under inert gas protection, resulting in extremely high equipment investment and operating costs. Existing solid-state battery technologies, whether inorganic or polymeric, are constrained by the interplay between material properties and solid-solid interface impedance. Simple physical mixing or mechanical pressing cannot fundamentally solve the problem of poor interfacial contact. Therefore, there is an urgent need for an innovative electrolyte structure design and fabrication method that can construct a solid electrolyte layer inside the battery with high ionic conductivity, tight interfacial contact, stable chemical / mechanical properties, and ease of large-scale production.

[0007] In view of this, this application proposes a method for preparing composite polymer solid electrolytes through in-situ polymerization. This method is expected to solve the solid-solid interface contact problem of traditional solid batteries, achieve a "molecular-level" tight bond between the electrode and the electrolyte, significantly reduce the interfacial impedance, and at the same time take into account good processability and potential low cost advantages, providing a brand-new technical path for promoting the commercial application of high-performance solid batteries. Summary of the Invention

[0008] This application aims to solve the solid-solid interface contact problem in traditional solid-state batteries, achieving a tight "molecular-level" bond between the electrode and the electrolyte, and significantly reducing interfacial impedance. Therefore, it proposes an "in-situ polymerization" technique, in which an electrolyte precursor solution is fully impregnated into the pores of the base film, followed by a polymerization reaction initiated within the electrolyte precursor solution to form a continuous interfacial bilayer solid electrolyte, resulting in an integrated polymer solid-state battery.

[0009] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application proposes an in-situ polymer solid-state battery, wherein the polymer solid-state battery is assembled by sequentially stacking a positive electrode / positive electrode-side solid electrolyte, a base film B coated with an electrolyte precursor solution B, and a negative electrode sheet into a battery structure, and is obtained by in-situ ring-opening polymerization reaction after being placed in an environment of 10~50°C for 1~48 hours.

[0010] As a specific solution in this application, the positive electrode / positive electrode side solid electrolyte is prepared by combining the positive electrode sheet with a base film A coated with an electrolyte precursor solution A and then maintaining it at 40~100℃ for 0.5~5 hours to undergo an in-situ polymerization reaction.

[0011] As a specific solution in this application, the electrolyte precursor solution A is prepared by mixing polymer precursor monomers, lithium salts, initiators and crosslinking agents at a weight ratio of (75~42.5):(15~42.5):5:(5~10) at room temperature.

[0012] As a specific embodiment of the technical solution in this application, the polymer precursor monomer is selected from at least one of butyl acrylate and butyl methacrylate, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the initiator is selected from at least one of azobisisobutyronitrile and azobisisoheptanenitrile, and the crosslinking agent is selected from at least one of polyethylene glycol diacrylate, methacryloxypropyltrimethylsilane, styrene, tetraethylene glycol dimethacrylate, and glycidyl methacrylate.

[0013] As a specific solution in the technical solution of this application, the positive electrode sheet is obtained by coating a positive electrode mixed slurry onto a current collector and drying it. The positive electrode mixed slurry is prepared by mixing positive electrode active material, binder and conductive agent in a mass ratio of (80~98):(1~15):(1~10).

[0014] As a specific embodiment of the technical solution in this application, the positive electrode active material is selected from at least one of lithium cobalt oxide, lithium iron phosphate, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, spinel nickel-manganese oxide, and lithium-rich manganese-based materials; the binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethyl cellulose, styrene-butadiene rubber, and polyvinyl alcohol; and the conductive agent is selected from at least one of graphite, carbon nanotubes, and graphene.

[0015] As a specific embodiment of the technical solution of this application, the electrolyte precursor solution B is prepared by stirring an epoxy-containing cyclic ether, lithium salt, initiator and organic additive at room temperature in the following weight ratio (2.06%~90.91%): (0.91%~81.82%): (0.007%~8.26%): (0%~30%).

[0016] As a specific embodiment of the technical solution in this application, the cyclic ether containing epoxy groups is a monocyclic or polycyclic cyclic ether compound; the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI); the initiator is selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorooxalate borate, and aluminum trifluoromethanesulfonate; and the organic additive is selected from at least one of propylene carbonate, ethylene carbonate, and fluoroethylene carbonate.

[0017] As a specific solution in the technical solution of this application, the negative electrode sheet is prepared by coating a negative electrode active material onto a current collector and then drying it. The negative electrode active material is selected from at least one of graphite, silicon / carbon composite material, silicon suboxide, lithium titanate, and lithium metal.

[0018] As a specific solution in this application, the base membrane is selected from at least one of polyethylene (PE), polypropylene (PP), ceramic-coated polypropylene (PP) membrane, ceramic-coated polyethylene (PE) membrane, double-layer polypropylene (PP) / polyethylene (PE) composite membrane, triple-layer polypropylene (PP) / polyethylene (PE) / polypropylene (PP) composite membrane, aramid (PI) membrane, polymer fiber membrane and inorganic fiber membrane.

[0019] Secondly, this application provides a method for preparing a polymer solid-state battery according to any one of claims 1 to 10, wherein the preparation method includes the following steps: (i) Prepare electrolyte precursor solution A by mixing polymer precursor monomer, lithium salt, initiator and crosslinking agent in a weight ratio of (75~42.5):(15~42.5):5:(5~10), and coat electrolyte precursor solution A onto the base film. (ii) A slurry is prepared by mixing positive electrode active material, binder and conductive agent in a mass ratio of (80~98):(1~15):(1~10), coating the slurry onto the current collector and drying it to obtain a positive electrode sheet; (III) The positive electrode sheet is combined with the base film A coated with electrolyte precursor solution A, and the mixture is kept at 40~100℃ for 0.5~5 hours to carry out in-situ polymerization reaction to obtain the positive electrode / positive electrode side solid electrolyte. (iv) Prepare electrolyte precursor solution B by mixing and stirring cyclic ethers containing epoxy groups, lithium salts, initiators and organic additives in a weight ratio of (2.06%~90.91%):(0.91%~81.82%):(0.007%~8.26%):(0%~30%). Coat electrolyte precursor solution B onto a base film; and coat the negative electrode active material onto a current collector to prepare a negative electrode sheet. (v) The positive electrode / positive electrode side solid electrolyte obtained in (iii), the base film B coated with electrolyte precursor solution B obtained in step (iv) and the negative electrode sheet are sequentially stacked and assembled into a battery structure, and then placed in an environment of 10~50℃ for 1~48 hours to undergo in-situ ring-opening polymerization reaction to obtain an integrated polymer solid battery.

[0020] Compared with existing technologies, the advantages of this application are: through innovative electrolyte precursor solution design, in-situ polymerization triggering, and interface integrated molding process, a solid-state battery with a bilayer structure is fabricated. The synergistic design of bilayer electrolytes on the positive and negative electrode sides achieves an interface integrated structure with molecular-level contact. The positive electrode side uses an in-situ polymerized solid electrolyte containing an acrylate crosslinking network, possessing high rigidity support and excellent ionic conductivity (>10). -4(S / cm); On the negative electrode side, a flexible polymer layer is formed by ring-opening polymerization of epoxy cyclic ether monomers, which can fully encapsulate negative electrode materials with large volume changes, such as silicon-based materials, effectively alleviating interfacial stress. This structure reduces the battery interfacial impedance by 40-60% compared to traditional solid-state batteries, significantly improving ion transport efficiency and battery rate performance, and significantly reducing interfacial impedance. A ceramic-coated PP / PE porous substrate membrane is used as the electrolyte carrier, which can effectively block lithium dendrite penetration and prevent internal short circuits; the epoxy resin network generated on the negative electrode side has high oxidation resistance (>4.5 V), which can be matched with high-voltage systems such as high-nickel positive electrodes, widening the battery voltage window and enhancing electrochemical stability, thereby improving battery safety performance. The electrolyte precursor solution B can complete the ring-opening polymerization reaction at a low temperature of 10~50℃, overcoming the limitation of traditional solid-state electrolyte preparation requiring high-temperature treatment (>80℃). This low-temperature process avoids structural damage to heat-sensitive materials (such as some polymer binders, high-voltage positive electrode active materials, etc.), which is beneficial to expanding the range of material selection and improving the overall compatibility and consistency of the battery. By employing a stepwise in-situ polymerization strategy, a three-dimensional cross-linked network is formed sequentially at the cathode / electrolyte and electrolyte / anode interfaces, achieving continuous ion transport channels from the cathode to the solid electrolyte and then to the anode. This enhances the interfacial mechanical strength and chemical stability, effectively suppressing interfacial degradation and side reactions during cycling. Therefore, this application has significant advantages in improving the interfacial compatibility, safety performance, and process feasibility of solid-state batteries, providing a new technical path for the development of high-performance, high-reliability solid-state batteries. Attached Figure Description

[0021] Figure 1 This is a structural diagram of the polymer solid-state battery proposed in the embodiments of this application; Figure 2 This is a flowchart illustrating the preparation method of the polymer solid-state battery proposed in the embodiments of this application; Figure 3 The following are capacity retention diagrams for embodiments and comparative examples 1-4 of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described more clearly and completely below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Example

[0023] Preparation method of polymer solid-state battery (1) Preparation of electrolyte precursor solution Electrolyte precursor solution A: Weigh 30g butyl acrylate, 12.5g lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2.5g azobisisobutyronitrile, and 5g polyethylene glycol diacrylate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution A. Electrolyte precursor solution B: Weigh 40g of polycyclic ether containing epoxy groups, 40g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 0.5g of lithium hexafluorophosphate, and 19.5g of ethylene carbonate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution B.

[0024] (2) Preparation of solid electrolyte material C on the positive electrode / positive electrode side A three-layer 25μm ceramic-coated polypropylene (PP) / polyethylene (PE) / ceramic-coated polypropylene (PP) composite membrane was selected, and the pores of the composite membrane were fully impregnated with electrolyte precursor solution A. At the same time, nickel-cobalt-manganese ternary material, binder (polyvinylidene fluoride, etc.), and conductive agent (carbon nanotubes, etc.) were slurried at a mass ratio of 85:10:5 and coated with a current collector to obtain a positive electrode sheet. The positive electrode sheet was stacked with a base film impregnated with electrolyte precursor solution A, and heated at 60℃ for 2 hours to allow the polymer precursor in electrolyte precursor solution A to undergo an in-situ polymerization reaction under the action of the initiator azobisisobutyronitrile, forming a solid electrolyte layer with a three-dimensional cross-linked network, thus obtaining the positive electrode / positive electrode side solid electrolyte material C.

[0025] (3) Polymer solid-state battery assembly Take electrolyte precursor solution B and wet another porous base membrane (same type as step 2); coat the current collector with negative electrode active materials such as graphite and silicon / carbon composite to obtain a negative electrode sheet; stack and assemble the battery in the order of positive electrode / solid electrolyte material C on the positive electrode side / base membrane wetted with electrolyte precursor solution B / negative electrode sheet, and let it stand at 30°C for 24 hours to allow the polycyclic ether containing epoxy groups in solution B to complete the in-situ ring-opening polymerization reaction under the action of lithium hexafluorophosphate initiator, forming a bilayer solid electrolyte structure with a continuous interface, and obtaining an integrated polymer solid battery.

[0026] Comparative Example 1 Preparation method of polymer solid-state battery (1) Preparation of electrolyte precursor solution Electrolyte precursor solution A: Weigh 30g butyl acrylate, 12.5g lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2.5g azobisisobutyronitrile, and 5g polyethylene glycol diacrylate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution A. (2) Preparation of solid electrolyte material C on the positive electrode / positive electrode side A three-layer 25μm ceramic-coated polypropylene (PP) / polyethylene (PE) / ceramic-coated polypropylene (PP) composite membrane was selected, and the pores of the composite membrane were fully impregnated with electrolyte precursor solution A. At the same time, nickel-cobalt-manganese ternary material, binder (polyvinylidene fluoride, etc.), and conductive agent (carbon nanotubes, etc.) were slurried at a mass ratio of 85:10:5 and coated with a current collector to obtain a positive electrode sheet. The positive electrode sheet was stacked with a base film impregnated with electrolyte precursor solution A, and heated at 60℃ for 2 hours to allow the polymer precursor in electrolyte precursor solution A to undergo an in-situ polymerization reaction under the action of the initiator azobisisobutyronitrile, forming a solid electrolyte layer with a three-dimensional cross-linked network, thus obtaining the positive electrode / positive electrode side solid electrolyte material C.

[0027] (3) Polymer solid-state battery assembly A negative electrode sheet is obtained by coating a current collector with negative electrode active materials such as graphite and silicon / carbon composite; the battery is assembled by stacking the positive electrode / positive side solid electrolyte material C / negative electrode sheet in sequence, and polymerizing it at 80℃ for 2 hours to form a bilayer solid electrolyte structure with a continuous interface, thus obtaining a polymer solid-state battery.

[0028] Compared with the Example 1, Comparative Example 1 only uses the electrolyte precursor solution A system. The base film soaked in the electrolyte precursor solution A is directly assembled with the negative electrode (silicon / carbon composite), omitting the solution B layer. The polymer solid-state battery is obtained by polymerization reaction at 80°C for 2 hours. Other conditions are the same as in Example 1.

[0029] Comparative Example 2 Preparation method of polymer solid-state battery (1) Preparation of electrolyte precursor solution Electrolyte precursor solution A: Weigh 30g butyl acrylate, 12.5g lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2.5g azobisisobutyronitrile, and 5g polyethylene glycol diacrylate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution A. Electrolyte precursor solution B: Weigh 40g of polycyclic ether containing epoxy groups, 40g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 0.5g of lithium hexafluorophosphate, and 19.5g of ethylene carbonate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution B.

[0030] (2) Preparation of solid electrolyte material C on the positive electrode / positive electrode side A three-layer 25μm ceramic-coated polypropylene (PP) / polyethylene (PE) / ceramic-coated polypropylene (PP) composite membrane was selected, and the pores of the composite membrane were fully impregnated with electrolyte precursor solution A. At the same time, nickel-cobalt-manganese ternary material, binder (polyvinylidene fluoride, etc.), and conductive agent (carbon nanotubes, etc.) were slurried at a mass ratio of 85:10:5 and coated with a current collector to obtain a positive electrode sheet. The positive electrode sheet was stacked with a base film impregnated with electrolyte precursor solution A, and heated at 60℃ for 2 hours to allow the polymer precursor in electrolyte precursor solution A to undergo an in-situ polymerization reaction under the action of the initiator azobisisobutyronitrile, forming a solid electrolyte layer with a three-dimensional cross-linked network, thus obtaining the positive electrode / positive electrode side solid electrolyte material C.

[0031] (3) Polymer solid-state battery assembly Take electrolyte precursor solution B and wet another porous base membrane (same type as step 2); coat the current collector with negative electrode active materials such as graphite and silicon / carbon composite to obtain a negative electrode sheet; stack and assemble the battery in the order of positive electrode / positive side solid electrolyte material C / base membrane wetted with electrolyte precursor solution B / negative electrode sheet, and let it stand at 80°C for 24 hours to allow solution B to undergo a polymerization reaction to form a double-layer solid electrolyte structure, thus obtaining an integrated polymer solid battery.

[0032] Compared with Example 1, Comparative Example 2 changed the polymerization temperature of electrolyte precursor solution B to 80°C, while other conditions remained the same as in Example 1.

[0033] Comparative Example 3 Preparation method of polymer solid-state battery (1) Preparation of electrolyte precursor solution Electrolyte precursor solution A: Weigh 30g butyl acrylate, 12.5g lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2.5g azobisisobutyronitrile, and 5g polyethylene glycol diacrylate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution A. Electrolyte precursor solution B: Weigh 40g of polycyclic ether containing epoxy groups, 40g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 0.5g of lithium hexafluorophosphate, and 19.5g of ethylene carbonate and stir at room temperature for 2 hours to form a homogeneous and transparent electrolyte precursor solution B.

[0034] (2) Preparation of solid electrolyte material C on the positive electrode / positive electrode side A positive electrode sheet is obtained by preparing a ternary material of nickel, cobalt, and manganese, a binder (such as polyvinylidene fluoride), and a conductive agent (such as carbon nanotubes) in a mass ratio of 85:10:5 and coating it with a current collector. An electrolyte precursor solution A is directly coated onto the surface of the positive electrode sheet and heated at 60°C for 2 hours to undergo a polymerization reaction to form a solid electrolyte layer, thus obtaining the positive electrode / positive electrode side solid electrolyte material C.

[0035] (3) Polymer solid-state battery assembly Take electrolyte precursor solution B and wet another porous base membrane (same type as step 2); coat the current collector with negative electrode active materials such as graphite and silicon / carbon composite to obtain a negative electrode sheet; stack and assemble the battery in the order of positive electrode / solid electrolyte material C on the positive electrode side / base membrane wetted with electrolyte precursor solution B / negative electrode sheet, and let it stand at 30°C for 24 hours to allow the polycyclic ether containing epoxy groups in solution B to complete the in-situ ring-opening polymerization reaction under the action of lithium hexafluorophosphate initiator, forming a bilayer solid electrolyte structure with a continuous interface, and obtaining an integrated polymer solid battery.

[0036] Compared with the example, in Comparative Example 3, the electrolyte precursor solution A was not fully impregnated into the pores of the polypropylene (PP) / polyethylene (PE) / ceramic-coated polypropylene (PP) composite membrane. Instead, the electrolyte precursor solution A was directly coated onto the surface of the positive electrode for polymerization. Other conditions were the same as in Example 1.

[0037] Comparative Example 4 In Comparative Example 4, compared to Example 1, all solid components were replaced with 1M LiPF6 / EC:DMC (1:1) electrolyte, while other conditions remained the same as in Example 1.

[0038] The test results of the examples and comparative examples 1-4 are shown in Table 1.

[0039] Table 1 According to the test results in Table 1, Example 1 achieved a capacity retention rate of 98.2% over 100 cycles, while Comparative Example 1 only achieved 76.5%. Simultaneously, the negative electrode expansion rate of Example 1 was ≤8%, significantly lower than the 22% of Comparative Example 1. This demonstrates that the flexible polymer layer formed by solution B effectively adapts to the large volume changes of the silicon-carbon negative electrode, preventing cracking of active material particles (comparative Example 2 observed silicon particle cracking), thus ensuring the structural integrity and long cycle life of the electrode. In Comparative Example 2, an increased LiF content was detected, indicating severe side reactions at the interface between the rigid electrolyte and the negative electrode, consuming active lithium and leading to a decrease in initial efficiency (69.3%). Example 1, however, showed a higher initial efficiency (81.5%) and a "normal" interface, indicating that solution B formed a more stable interface, effectively suppressing the formation of harmful byproducts. Comparative Example 2 changed the polymerization temperature of solution B from 30℃ to 80℃, and the performance difference reflects the superiority of the low-temperature polymerization process. High-temperature polymerization may damage the already formed interface or trigger unnecessary side reactions, leading to a decrease in the initial efficiency of Comparative Example 2 (69.3% vs. 81.5%). The low-temperature polymerization (30°C) conditions of the embodiment are mild, better protecting the interface and forming a continuous interface with lower impedance and stronger ion transport capability. Comparative Example 3 directly coats solution A onto the surface of the positive electrode for polymerization, rather than immersing it in a ceramic-coated PP / PE / PP composite film. The performance difference demonstrates the crucial role of the porous substrate film: the embodiment uses a substrate film with excellent electrolyte thickness uniformity (±1.5 μm), while Comparative Example 3 has poor uniformity (±8.2 μm). Uneven thickness can easily lead to excessive local current, inducing lithium dendrite formation. Therefore, the embodiment passes the needle penetration test, while Comparative Example 3 fails. This highlights the irreplaceable role of the substrate film in uniformly wetting the electrolyte, providing mechanical support, and preventing lithium dendrite formation. Comparative Example 4 uses a traditional liquid electrolyte, and its comprehensive performance disadvantages reflect the fundamental improvement brought by the all-solid-state battery design of this solution. The embodiment uses an all-solid-state structure and passes the hot box test, while the liquid battery (Comparative Example 4) fails. This is the most direct manifestation of how solid-state batteries address safety concerns. The energy density of this embodiment is as high as 382 Wh / kg, far superior to the 280 Wh / kg of Comparative Example 4. This is due to the thinner and lighter solid electrolyte, which may allow for the use of higher capacity electrode materials. The self-discharge rate of this embodiment is extremely low (0.5% / month), compared to 2.1% / month for Comparative Example 4. This indicates that the solid-state system has superior chemical stability and interfacial sealing, resulting in less leakage. Although liquid ionic conductivity is generally higher, this embodiment achieves a high capacity retention of 89.3% at 5C rate through excellent interfacial design, far exceeding that of Comparative Example 1 (63.1%), indicating that its interfacial impedance has been optimized to a very low level.

[0040] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An in-situ polymerized polymer solid-state battery, characterized by, The polymer solid-state battery is prepared by stacking the positive electrode / positive electrode side solid-state electrolyte, the base film B coated with the electrolyte precursor solution B and the negative electrode sheet in sequence to form a battery structure, and then standing in an environment of 10-50℃ for 1-48 hours to generate an in-situ ring-opening polymerization reaction.

2. The polymer solid battery according to claim 1, characterized by, The positive electrode / positive electrode side solid-state electrolyte is prepared by compounding the positive electrode sheet with the base film A coated with the electrolyte precursor solution A, and then standing in an environment of 40-100℃ for 0.5-5 hours to generate an in-situ polymerization reaction. 3.The polymer solid-state battery of claim 2, wherein, The electrolyte precursor solution A is prepared by mixing a polymer precursor monomer, a lithium salt, an initiator and a crosslinking agent at room temperature in a weight ratio of (75-42.5):(15-42.5):5:(5-10). 4.The polymer solid-state battery according to claim 3, characterized by, The polymer precursor monomer is at least one selected from butyl acrylate and butyl methacrylate, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the initiator is at least one selected from azobisisobutyronitrile and azobisisoheptyl nitrile, and the crosslinking agent is at least one selected from polyethylene glycol diacrylate, methacryloyloxypropyltrimethylsilane, styrene, triethylene glycol dimethacrylate and glycidyl methacrylate. 5.The polymer solid-state battery of claim 2, wherein, The positive electrode sheet is obtained by coating a positive electrode mixed slurry on a current collector and drying, and the positive electrode mixed slurry is prepared by mixing a positive electrode active material, a binder and a conductive agent in a mass ratio of (80-98):(1-15):(1-10). 6.The polymer solid-state battery according to claim 5, characterized by, The positive electrode active material is at least one selected from lithium cobaltate, lithium iron phosphate, nickel-cobalt-manganese ternary material, nickel-cobalt-aluminum ternary material, spinel lithium nickel manganese oxide and lithium-rich manganese-based material, the binder is at least one selected from polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethyl cellulose, butadiene-styrene rubber and polyvinyl alcohol, and the conductive agent is at least one selected from graphite, carbon nanotube and graphene. 7.The polymer solid state battery of claim 1, wherein, The electrolyte precursor solution B is prepared by stirring an epoxy group-containing cyclic ether, a lithium salt, an initiator and an organic additive at room temperature in a weight ratio of (2.06%-90.91%):(0.91%-81.82%):(0.007%-8.26%):(0%-30%). 8.The polymer solid-state battery according to claim 7, characterized by, The epoxy group-containing cyclic ether is a monocyclic or polycyclic cyclic ether compound, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the initiator is at least one selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoro oxalate borate and aluminum trifluoromethanesulfonate, and the organic additive is at least one selected from propylene carbonate, ethylene carbonate and fluoroethylene carbonate. 9.The polymer solid state battery of claim 1, wherein, The negative electrode sheet is prepared by coating a negative electrode active material on a current collector and drying, and the negative electrode active material is at least one selected from graphite, silicon / carbon composite material, silicon monoxide, lithium titanate and metallic lithium. 10.The polymer solid-state battery of claim 1, wherein, The base film is at least one selected from polyethylene film (PE), polypropylene film (PP), ceramic-coated polypropylene (PP) film, ceramic-coated polyethylene (PE) film, double-layer polypropylene (PP) / polyethylene (PE) composite film, three-layer polypropylene (PP) / polyethylene (PE) / polypropylene (PP) composite film, aramid (PI) separator, polymer fiber film and inorganic fiber film.

11. A method for producing the polymer solid-state battery according to any one of claims 1 to 10, characterized by, The preparation method comprises the following steps: (1) mixing the polymer precursor monomer, lithium salt, initiator and crosslinking agent according to the weight ratio of (75-42.5):(15-42.5):5:(5-10) to prepare an electrolyte precursor solution A, and coating the electrolyte precursor solution A on a base film; (2) mixing the positive electrode active material, binder and conductive agent according to the mass ratio of (80-98):(1-15):(1-10) to prepare a slurry, coating the slurry on a current collector, and drying to obtain a positive electrode sheet; (3) compounding the positive electrode sheet with the base film A coated with the electrolyte precursor solution A, and keeping at 40-100 DEG C for 0.5-5 hours to generate an in-situ polymerization reaction, thereby preparing a positive electrode / positive electrode side solid electrolyte; (4) mixing and stirring the cyclic ether containing an epoxy group, lithium salt, initiator and organic additive according to the weight ratio of (2.06%-90.91%):(0.91%-81.82%):(0.007%-8.26%):(0%-30%) to prepare an electrolyte precursor solution B, coating the electrolyte precursor solution B on a base film, and coating a negative electrode active material on a current collector to prepare a negative electrode sheet; (5) stacking the positive electrode / positive electrode side solid electrolyte prepared in (3), the base film B coated with the electrolyte precursor solution B prepared in (4) and the negative electrode sheet in sequence to form a battery structure, and keeping at 10-50 DEG C for 1-48 hours to generate an in-situ ring-opening polymerization reaction, thereby obtaining an integrated polymer solid-state battery.

Images