Gel electrolyte, preparation method thereof and application of gel electrolyte in solid-state lithium battery

Abstract

In order to solve the problem of low room-temperature self-repairing efficiency of the gel electrolyte, the invention provides the gel electrolyte, the preparation method thereof and the application of the gel electrolyte in the solid-state lithium battery, the gel electrolyte is prepared by carrying out free radical copolymerization on a pre-polymerized solution through thermal initiation, and the self-repairing efficiency of the gel electrolyte at room temperature is improved through a component compatibility regulation mechanism. The polymer network structure of the gel electrolyte is a dynamic ion synergetic association network, and the pre-polymerization liquid comprises a hydrophilic / amphiphilic functional monomer, an acrylate monomer or a fluorinated acrylate monomer, an initiator and an organic electrolyte. According to the prepared gel electrolyte, a non-covalent association body in a dynamic network is similar to a cross-linking point, so that the gel electrolyte and dynamic reversible recombination can be effectively enhanced, and mechanical brittleness caused by a chemical cross-linking agent is avoided; the linear polymer containing abundant functional groups is cooperated to greatly improve the chain segment movement capability, so that the gel electrolyte is endowed with excellent flexibility, adhesion, instantaneous self-repairing and high ion conductivity, and the solid-state lithium battery can safely and stably circulate for a long time.

Description

Technical Field

[0001] This invention belongs to the field of solid-state lithium battery technology, specifically relating to a gel electrolyte, its preparation method, and its application in solid-state lithium batteries. Background Technology

[0002] Currently, distributed photovoltaic and deep-sea wind power are being rapidly deployed, and the scale of flexible and controllable loads such as electric vehicles and air conditioners is growing rapidly. This poses a significant challenge to the safety and stability of the power grid, necessitating research on high-safety and intelligent collaborative new energy storage technologies. The Special Action Plan for the Large-Scale Construction of New Energy Storage (2025-2027) points out that lithium-ion battery energy storage remains the primary technology route for new energy storage. Among them, solid-state lithium batteries have become a core technology in the new energy field and a key focus in the energy storage field due to their key advantages such as high safety and high energy density. However, poor solid-solid interface contact between the solid electrolyte and the electrode, as well as significant internal mechanical effects during operation, can easily lead to ion transport interruption, interface failure, and even certain safety risks.

[0003] Polymer gel electrolytes exhibit unique advantages due to their excellent flexibility, interfacial contact, and high ionic conductivity at room temperature. In particular, combining them with in-situ polymerization technology can further improve the electrolyte-electrode interface contact and enhance the cycle performance of solid-state lithium batteries. However, to ensure high ionic conductivity at room temperature for normal battery operation, the polymer content in conventional in-situ polymerization systems is usually very small (generally, the monomer content in the prepolymer liquid is <10 wt%), and the resulting gel electrolytes are often brittle (poor ductility, easily broken), unable to adapt to changes in electrode volume and thus damaging the electrolyte structure. Therefore, by introducing dynamic covalent bonds, hydrogen bonds, and supramolecular interactions to enhance the self-healing ability of gel electrolytes, it is possible to construct smart solid-state lithium batteries that can self-repair damage. However, existing self-healing gel electrolytes suffer from low room temperature self-healing efficiency and generally long repair times (several hours or even tens of hours) due to the small polymer content limiting inter-chain contact or the rigidity of commonly used self-healing structural units (such as ureidopyrimidinone, UPy), resulting in poor chain mobility. This makes it difficult to match the charge-discharge cycle process to quickly and effectively repair microcracks and interfacial damage (especially at high rates). Therefore, there is an urgent need to develop a novel polymer gel electrolyte that can quickly self-heal and has excellent interfacial dynamic adaptability to promote the development of smart solid-state lithium batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a dynamic adaptive instantaneous self-healing gel electrolyte. By constructing a gel electrolyte with a dynamic ion synergistic association network in situ through a component compatibility regulation mechanism, the dynamic stability of the conformal tight interface between the gel electrolyte and the electrode is enhanced during continuous electrochemical cycling (mechanical deformation), thereby improving the long-term safe and stable cycling of smart solid-state lithium batteries at high rates.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A gel electrolyte is prepared by free radical copolymerization of a prepolymer solution via thermal initiation. Through a component compatibility regulation mechanism, the polymer network structure of the gel electrolyte is a dynamic ion-co-associative network. The prepolymer solution includes hydrophilic / amphiphilic functional monomers (i.e., hydrophilic functional monomers or amphiphilic functional monomers), acrylate monomers or fluorinated acrylate monomers, an initiator, and an organic electrolyte. The hydrophilic / amphiphilic functional monomers have limited solubility in the organic electrolyte. Component compatibility is regulated through multiple interactions (such as hydrogen bonding, dipole-dipole, ion-dipole interactions, etc.) with acrylate or fluorinated acrylate monomers to form a dynamically stable prepolymer solution.

[0007] The structure of the hydrophilic / amphiphilic functional monomer is Formula I, and the structure of the acrylate monomer or fluorinated acrylate monomer is Formula II;

[0008] Formula I; Formula II;

[0009] In structural formula I, R1 is independently selected from H, CH3, CH2CH3, (CH2)2CH3, and the functional group M1 is independently selected from COOH, CONH2, CON(CH3)2, COO(CH3)2OH;

[0010] In structural formula II, R2 is independently selected from H and CH3, and the functional group M2 is independently selected from COOCH3, COO(CH2)3CH3, COOCH2CF3, COOCH2CF2CF3, COOCH2(CF2)2H, and COOCH2CF2CFHCF3.

[0011] The total number of monomers accounts for 20 to 50 wt% of the mass of the prepolymer solution, and the proportion of higher quality monomers is 30 to 40 wt%.

[0012] Furthermore, the molar ratio of the hydrophilic / amphiphilic functional monomer to the acrylate monomer or fluorinated acrylate monomer is 1:6 to 1:1.

[0013] Preferably, the molar ratio of the hydrophilic / amphiphilic functional monomer to the acrylate monomer or fluorinated acrylate monomer is 1:5 to 1:3.

[0014] Furthermore, the initiator is any one of azobisisobutyronitrile (AIBN) and benzoyl peroxide, and the molar percentage of the initiator relative to the total number of monomers is 0.1 to 2.0 mol.

[0015] Furthermore, the organic electrolyte includes a solvent, a functional additive, and a lithium salt. The solvent is a carbonate solvent or an ether solvent, and the volume ratio of the solvent to the functional additive is 7:3 to 9.5:0.5.

[0016] Further, the carbonate solvent is one or more of ethyl methyl carbonate (EMC), methyl propionate (MP), dimethyl carbonate (DMC), ethylene carbonate (EC), and propylene carbonate (PC); the ether solvent is one or more of 1,2-dimethoxyethane (DME), hydrofluoroether (HFE), dibutyl ether, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.

[0017] Furthermore, the functional additive is any one of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and vinyl sulfate (DTD).

[0018] Further, the lithium salt is one or more combinations of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium difluorooxalate borate (LiDFOB), and lithium nitrate (LiNO3), and the total molar concentration of the lithium salt in the organic electrolyte ranges from 1 to 4 mol / L. -1 .

[0019] The present invention further proposes a method for preparing a gel electrolyte, comprising the following steps:

[0020] Hydrophilic or amphiphilic functional monomers, acrylate monomers or fluorinated acrylate monomers and initiators are introduced into an organic electrolyte and mixed and stirred at room temperature until homogeneous to obtain a prepolymer; the prepolymer is then subjected to thermally initiated free radical copolymerization to obtain a gel electrolyte.

[0021] Furthermore, the stirring time is 1 to 12 hours, and the polymerization temperature is 50 to 90 degrees Celsius. o C, polymerization time is 6~24 h.

[0022] The present invention also proposes a solid-state lithium battery, comprising a positive electrode, a gel electrolyte and a negative electrode, wherein the gel electrolyte is a gel electrolyte prepared by thermally initiated in-situ free radical copolymerization of a prepolymer liquid within the battery.

[0023] Furthermore, the prepolymer solution is injected into the battery and allowed to stand for 10 to 40 hours, and the polymerization temperature is 50 to 90 degrees Celsius. o C, polymerization time is 6 ~ 24 h.

[0024] Furthermore, the cathode material is any one of lithium iron phosphate (LFP) cathode, nickel-cobalt-manganese ternary (NCM811) cathode, lithium cobalt oxide (LCO) cathode, and lithium manganese oxide (LMO) cathode.

[0025] Furthermore, the negative electrode material is any one of lithium metal (Li) negative electrode, silicon carbon (SiC) negative electrode, graphite (C) negative electrode, and lithium titanate (LTO) negative electrode.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] For the first time, hydrophilic / amphiphilic functional monomers are introduced into lithium-ion battery organic electrolytes. Component compatibility is regulated through multiple interactions (such as hydrogen bonding, dipole-dipole, and ion-dipole interactions) with (fluorinated) acrylate monomers to form a stable prepolymer. Furthermore, the dynamic differences in the interaction strength between different monomer / oligomer functional groups and the organic electrolyte during in-situ free radical copolymerization regulate the interaction modes between the polymer network, gradually evolving into a novel dynamic ion-synergistic association network. Compared to traditional in-situ gel electrolytes, the non-covalent associates in the dynamic network act as cross-linking points, effectively enhancing the gel electrolyte and dynamic reversible recombination, avoiding the mechanical brittleness caused by chemical cross-linking agents. The synergistic effect of linear polymers rich in functional groups significantly improves chain segment mobility, endowing the gel electrolyte with excellent flexibility, adhesion, instantaneous self-healing (≤10 s), and high ion conductivity. This results in a conformal, tight interface that expands and contracts synchronously with the electrodes, and maintains the integrity of the electrolyte, interface, and ion transport pathways during high-rate charge-discharge cycles. Meanwhile, functional groups (such as fluorine-containing groups) regulate the electron cloud density of polymers, broaden the electrochemical window of the electrolyte, and improve its (e)chemical stability, thereby forming a dynamically adaptive and stable electrolyte-electrode interface, which is committed to the long-term safe and stable cycling of smart solid-state lithium batteries. Attached Figure Description

[0028] Figure 1 (a) and (b) are optical photographs of Example 1 and Comparative Example 1 after thermally initiated free radical polymerization, respectively.

[0029] Figure 2 (a) and (b) are room temperature self-healing optical photographs of Example 1 and Comparative Example 2, respectively;

[0030] Figure 3 The image shown in the middle is a room temperature self-healing optical photograph of Example 2;

[0031] Figure 4 The image shown in the middle is a room temperature self-healing optical photograph of Example 3;

[0032] Figure 5 The image in the middle is a room temperature self-healing optical photograph of Example 4;

[0033] Figure 6 The image shown in the middle is a room temperature self-healing optical photograph of Example 5;

[0034] Figure 7 The image shown in the middle is a room temperature self-healing optical photograph of Example 6;

[0035] Figure 8 The image in the middle shows an optical photograph of the adhesion of Example 1 on different substrates;

[0036] Figure 9 The figure in the middle shows the room temperature electrochemical impedance spectroscopy (EIS) curve and ionic conductivity data of Example 1;

[0037] Figure 10 The image shows the long-term cycling curves of the Li|P(MAA1-co-TFEMA3)|LFP smart solid-state lithium battery prepared in Example 1 at 25°C and high rate (1 C).

[0038] Figure 11 The image shows the long-term cycling curves of the Li|P(MAA1-co-TFEMA4)|LFP smart solid-state lithium battery prepared in Example 2 at 25°C and high rate (1 C).

[0039] Figure 12 The image shows the long-term cycling curves of the Li|P(MAA1-co-TFM5)|LFP smart solid-state lithium battery prepared in Example 3 at 25°C and high rate (1 C).

[0040] Figure 13 The image shows the long-term cycling curve of the Li|P(AAm1-co-TFEMA4)|LFP smart solid-state lithium battery prepared in Example 6 at 25°C and high rate (1 C). Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] Example 1

[0043] A gel electrolyte, the prepolymer of which is composed of methacrylic acid (MAA), trifluoroethyl methacrylate (TFEMA), AIBN, EMC, FEC, and LiTFSI, wherein MAA is an amphiphilic functional monomer, TFEMA is a fluorinated acrylate monomer, AIBN is an initiator, EMC is a carbonate solvent, FEC is a functional additive, and LiTFSI is a lithium salt, and EMC, FEC, and LiTFSI constitute the organic electrolyte. The molar ratio of MAA to TFEMA monomers is 1:3, the molar percentage of AIBN relative to the total number of MAA and TFEMA monomers is 0.5 mol%; the volume ratio of EMC to FEC is 8:2, and the molar concentration of LiTFSI in the mixed solvent of EMC and FEC is 1 mol L. -1 The total number of monomers relative to the mass of the prepolymer solution is 30 wt%. The prepolymer solution is subjected to free radical copolymerization initiated by AIBN to obtain a dynamically adaptive, transiently self-healing gel electrolyte. Using LFP as the positive electrode and Li as the negative electrode, a Celgard 2500 separator and the prepolymer solution described in Example 1 are used to assemble a 2025 coin cell. In-situ free radical copolymerization initiated by AIBN yields a Li|P(MAA1-co-TFEMA3)|LFP smart solid-state lithium battery.

[0044] The specific preparation method and the gel electrolyte's molding state, mechanical properties, self-healing properties, adhesion, and electrochemical performance tests are as follows:

[0045] Add LiTFSI to the mixed solvent of EMC and FEC according to the specified molar ratio, and stir thoroughly until completely dissolved to obtain a molar concentration of 1 mol L. -1 The lithium-ion battery organic electrolyte was prepared by adding MAA and TFEMA in a 1:3 molar ratio to the above 1 mol L solution. -1 The organic electrolyte for lithium-ion batteries was stirred thoroughly again until homogeneous. Finally, AIBN was added to the mixture at a molar percentage of 0.5 mol% of the total monomers, and stirred thoroughly until homogeneous to obtain the prepolymer solution. The prepolymer solution was then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a dynamically adaptive, transient self-healing gel electrolyte. The prepolymer solution was injected into a lithium battery assembled with Li and LFP, allowed to stand for 10 h, and then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a Li|P(MAA1-co-TFEMA3)|LFP smart solid-state lithium battery. The experimental results described in Example 1 are as follows: Figure 1 As shown in (a), the gel electrolyte strengthens the matrix through the formation of a dynamic ion-co-association network, resulting in a shaped, colorless, and transparent state; Figure 2 (a) The gel electrolyte shown is flexible and highly stretchable; at room temperature, the fracture surface can self-repair and achieve high stretching again after only 10 seconds of contact. Figure 8The gel electrolyte shown exhibits good adhesion to various substrates such as LFP electrodes, Li sheets, plastics, and glass; for example... Figure 9 The gel electrolyte shown has a high efficiency of 2.75 mS / cm. -1 The room temperature ionic conductivity; such as Figure 10 As shown, the Li|P(MAA1-co-TFEMA3)|LFP smart solid-state lithium battery, after activation at room temperature, undergoes charge-discharge cycling at room temperature (25 ℃) and a high rate (1 C) for 300 cycles. The coulombic efficiency remains at 99.99%, and the reversible charge-discharge capacity is still 126.2 mAh g⁻¹. -1 The capacity retention rate is as high as 98%.

[0046] Example 2

[0047] A gel electrolyte, the prepolymer of which is composed of methacrylic acid (MAA), trifluoroethyl methacrylate (TFEMA), AIBN, EMC, FEC, and LiTFSI, wherein MAA is an amphiphilic functional monomer, TFEMA is a fluorinated acrylate monomer, AIBN is an initiator, EMC is a carbonate solvent, FEC is a functional additive, and LiTFSI is a lithium salt, and EMC, FEC, and LiTFSI constitute the organic electrolyte. The molar ratio of MAA to TFEMA monomers is 1:4, the molar percentage of AIBN relative to the total number of MAA and TFEMA monomers is 0.5 mol%; the volume ratio of EMC to FEC is 8:2, and the molar concentration of LiTFSI in the mixed solvent of EMC and FEC is 1 mol L. -1 The total number of monomers relative to the mass of the prepolymer solution is 35 wt%. The prepolymer solution is subjected to free radical copolymerization initiated by AIBN to obtain a dynamically adaptive, transiently self-healing gel electrolyte. Using LFP as the positive electrode and Li as the negative electrode, a Celgard 2500 separator and the prepolymer solution described in Example 2 are used to assemble a 2025 type coin cell. In-situ free radical copolymerization initiated by AIBN yields a Li|P(MAA1-co-TFEMA4)|LFP smart solid-state lithium battery.

[0048] The specific preparation method and the mechanical, self-healing, and electrochemical performance tests of the gel electrolyte are as follows:

[0049] Add LiTFSI to the mixed solvent of EMC and FEC according to the specified molar ratio, and stir thoroughly until completely dissolved to obtain a molar concentration of 1 mol L. -1 The lithium-ion battery organic electrolyte was prepared by adding MAA and TFEMA in a 1:4 molar ratio to the above 1 mol L solution. -1The organic electrolyte for lithium-ion batteries was stirred thoroughly again until homogeneous. Finally, AIBN was added to the mixture at a molar percentage of 0.5 mol% of the total monomers, and stirred thoroughly until homogeneous to obtain the prepolymer solution. The prepolymer solution was then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a dynamically adaptive, transient self-healing gel electrolyte. The prepolymer solution was injected into a lithium battery assembled with Li and LFP, allowed to stand for 10 h, and then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a Li|P(MAA1-co-TFEMA4)|LFP smart solid-state lithium battery. The experimental results described in Example 2 are as follows: Figure 3 As shown, the gel electrolyte is flexible and highly stretchable; the cross-section at room temperature can self-repair and achieve high stretching again after only 10 seconds of contact. Figure 11 As shown, the Li|P(MAA1-co-TFEMA4)|LFP smart solid-state lithium battery, after activation at room temperature, undergoes charge-discharge cycling at room temperature (25 ℃) and a high rate (1 C) for 250 cycles. The coulombic efficiency remains at 99.99%, and the reversible charge-discharge capacity is still 116.9 mAh g⁻¹. -1 The capacity retention rate is as high as 96%.

[0050] Example 3

[0051] A gel electrolyte, the prepolymer of which is composed of methacrylic acid (MAA), 2,2,3,3-tetrafluoropropyl methacrylate (TFM), AIBN, EMC, FEC, and LiTFSI, wherein MAA is an amphiphilic functional monomer, TFM is a fluorinated acrylate monomer, AIBN is an initiator, EMC is a carbonate solvent, FEC is a functional additive, and LiTFSI is a lithium salt, and EMC, FEC, and LiTFSI constitute an organic electrolyte. The molar ratio of MAA to TFM monomers is 1:5, the molar percentage of AIBN relative to the total number of MAA and TFM monomers is 0.5 mol%; the volume ratio of EMC to FEC is 8:2, and the molar concentration of LiTFSI in the mixed solvent of EMC and FEC is 1 mol L. -1 The total number of monomers relative to the mass of the prepolymer solution is 40 wt%. The prepolymer solution is subjected to free radical copolymerization initiated by AIBN to obtain a dynamically adaptive, transiently self-healing gel electrolyte. Using LFP as the positive electrode and Li as the negative electrode, a Celgard 2500 separator and the prepolymer solution described in Example 3 are used to assemble a 2025 type coin cell. In-situ free radical copolymerization initiated by AIBN yields a Li|P(MAA1-co-TFM5)|LFP smart solid-state lithium battery.

[0052] The specific preparation method and the mechanical, self-healing, and electrochemical performance tests of the gel electrolyte are as follows:

[0053] Add LiTFSI to the mixed solvent of EMC and FEC according to the specified molar ratio, and stir thoroughly until completely dissolved to obtain a molar concentration of 1 mol L. -1 The lithium-ion battery organic electrolyte was prepared by adding MAA and TFM in a 1:5 molar ratio to the above 1 mol / L solution. -1 The organic electrolyte for lithium-ion batteries was stirred thoroughly again until homogeneous. Finally, AIBN was added to the mixture at a molar percentage of 0.5 mol% of the total monomers, and stirred thoroughly until homogeneous to obtain the prepolymer solution. The prepolymer solution was then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a dynamically adaptive, transient self-healing gel electrolyte. The prepolymer solution was injected into a lithium battery assembled with Li and LFP, allowed to stand for 10 h, and then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a Li|P(MAA1-co-TFM5)|LFP smart solid-state lithium battery. The experimental results described in Example 3 are as follows: Figure 4 As shown, the gel electrolyte is flexible and highly stretchable; a cross-section at room temperature can self-repair and achieve high stretching again after only 10 seconds of contact. Figure 12 As shown, the Li|P(MAA1-co-TFM5)|LFP smart solid-state lithium battery, after activation at room temperature, undergoes charge-discharge cycling at room temperature (25 ℃) and a high rate (1 C) for 500 cycles. The coulombic efficiency remains at 99.93%, and the reversible charge-discharge capacity is still 114.6 mAh g⁻¹. -1 The capacity retention rate is as high as 92.5%.

[0054] Example 4

[0055] A gel electrolyte, the prepolymer of which is composed of methacrylic acid (MAA), trifluoroethyl methacrylate (TFEMA), AIBN, EMC, FEC, LiTFSI, and LiDFOB, wherein MAA is an amphiphilic functional monomer, TFEMA is a fluorinated acrylate monomer, AIBN is an initiator, EMC is a carbonate solvent, FEC is a functional additive, and LiTFSI and LiDFOB are lithium salts. EMC, FEC, LiTFSI, and LiDFOB constitute the organic electrolyte. The molar ratio of MAA to TFEMA monomers is 1:3, the molar percentage of AIBN relative to the total number of MAA and TFEMA monomers is 0.5 mol%; the volume ratio of EMC to FEC is 8:2, the molar ratio of LiTFSI to LiDFOB is 10:2, and the total molar concentration of the two lithium salts in the mixed solvent of EMC and FEC is 1 mol L. -1 The total number of monomers relative to the mass of the prepolymer is 20 wt%. The prepolymer is subjected to free radical copolymerization initiated by AIBN to obtain the dynamic adaptive transient self-healing gel electrolyte P (MAA1-co-TFEMA3).

[0056] The specific preparation method and the mechanical and self-healing properties tests of the gel electrolyte are as follows:

[0057] Add LiTFSI and LiDFOB to the mixed solvent of EMC and FEC according to the molar ratio, and stir thoroughly until completely dissolved to obtain a total molar concentration of 1 mol / L. -1 The lithium-ion battery organic electrolyte was prepared by adding MAA and TFEMA in a 1:3 molar ratio to the above 1 mol L solution. -1 The lithium-ion battery organic electrolyte was stirred thoroughly again until homogeneous. Finally, AIBN was added to the mixture at a molar percentage of 0.5 mol% of the total monomers, and stirred thoroughly until homogeneous to obtain the prepolymer solution. The prepolymer solution was then placed in a 70 ℃ oven for heat polymerization for 12 h to obtain the dynamically adaptive transient self-healing gel electrolyte P(MAA1-co-TFEMA3). The experimental results described in Example 4 are as follows... Figure 5 As shown, the gel electrolyte is flexible and highly stretchable, and the cross-section at room temperature can self-repair and achieve high stretching again after only 10 seconds of contact.

[0058] Example 5

[0059] A gel electrolyte, the prepolymer of which is composed of methacrylic acid (MAA), trifluoroethyl methacrylate (TFEMA), AIBN, MP, FEC, and LiFSI, wherein MAA is an amphiphilic functional monomer, TFEMA is a fluorinated acrylate monomer, AIBN is an initiator, MP is a carbonate solvent, FEC is a functional additive, and LiFSI is a lithium salt, and MP, FEC, and LiFSI constitute the organic electrolyte. The molar ratio of MAA to TFEMA monomers is 1:6, the molar percentage of AIBN relative to the total number of MAA and TFEMA monomers is 0.5 mol%; the volume ratio of MP to FEC is 9:1, and the molar concentration of LiFSI in the mixed solvent of MP and FEC is 1 mol L. -1 The total number of monomers relative to the mass of the prepolymer is 50 wt%. The prepolymer is subjected to free radical copolymerization initiated by AIBN to obtain the dynamic adaptive transient self-healing gel electrolyte P (MAA1-co-TFEMA6).

[0060] The specific preparation method and the mechanical and self-healing properties tests of the gel electrolyte are as follows:

[0061] Add LiFSI to the mixed solvent of MP and FEC according to the specified molar ratio, and stir thoroughly until completely dissolved to obtain a molar concentration of 1 mol L. -1 The lithium-ion battery organic electrolyte was prepared by adding MAA and TFEMA in a 1:6 molar ratio to the above 1 mol / L solution. -1The mixture was stirred thoroughly again until homogeneous in the lithium-ion battery organic electrolyte. Finally, 0.5 mol% of AIBN (based on the total molar percentage of monomers) was added to the mixture, and the mixture was stirred thoroughly until homogeneous to obtain the prepolymer solution. The prepolymer solution was then placed in a 70 °C oven for heat polymerization for 12 h to obtain the dynamically adaptive transient self-healing gel electrolyte P (MAA1-co-TFEMA6). The experimental results described in Example 5 are as follows... Figure 6 As shown, the gel electrolyte is flexible and highly stretchable, and the cross-section at room temperature can self-repair and achieve high stretching again after only 10 seconds of contact.

[0062] Example 6

[0063] A gel electrolyte, the prepolymer of which is composed of acrylamide (AAm), trifluoroethyl methacrylate (TFEMA), AIBN, EMC, FEC, and LiTFSI, wherein AAM is a hydrophilic functional monomer, TFEMA is a fluorinated acrylate monomer, AIBN is an initiator, EMC is a carbonate solvent, FEC is a functional additive, and LiTFSI is a lithium salt, and EMC, FEC, and LiTFSI constitute the organic electrolyte. The molar ratio of AAm to TFEMA monomers is 1:4, the molar percentage of AIBN relative to the total number of AAM and TFEMA monomers is 0.5 mol%; the volume ratio of EMC to FEC is 7:3, and the molar concentration of LiTFSI in the mixed solvent of EMC and FEC is 1 mol L. -1 The total number of monomers relative to the mass of the prepolymer solution is 50 wt%. The prepolymer solution is subjected to free radical copolymerization initiated by AIBN to obtain a dynamically adaptive, transiently self-healing gel electrolyte. Using LFP as the positive electrode and Li as the negative electrode, a Celgard 2500 separator and the prepolymer solution described in Example 6 are used to assemble a 2025 type coin cell. In-situ free radical copolymerization initiated by AIBN yields a Li|P(AAm1-co-TFEMA4)|LFP smart solid-state lithium battery.

[0064] The specific preparation method and the mechanical, self-healing, and electrochemical performance tests of the gel electrolyte are as follows:

[0065] Add LiTFSI to the mixed solvent of EMC and FEC according to the specified molar ratio, and stir thoroughly until completely dissolved to obtain a molar concentration of 1 mol L. -1 The lithium-ion battery organic electrolyte was prepared by adding AAm and TFEMA in a 1:4 molar ratio to the above 1 mol L solution. -1The organic electrolyte for lithium batteries was stirred thoroughly again until homogeneous. Finally, AIBN was added to the mixture at a molar percentage of 0.5 mol% of the total monomers, and stirred thoroughly until homogeneous to obtain the prepolymer solution. The prepolymer solution was then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a dynamically adaptive, transient self-healing gel electrolyte. The prepolymer solution was injected into a lithium battery assembled with Li and LFP, allowed to stand for 10 h, and then placed in a 70 ℃ oven for 12 h for heat polymerization to obtain a Li|P(AAm1-co-TFEMA4)|LFP smart solid-state lithium battery. The experimental results described in Example 6 are as follows: Figure 7 As shown, the gel electrolyte is flexible and highly stretchable; the cross-section at room temperature can self-repair and achieve high stretching again after only 10 seconds of contact. Figure 13 As shown, the Li|P(AAm1-co-TFEMA4)|LFP smart solid-state lithium battery, after activation at room temperature, undergoes charge-discharge cycling at room temperature (25 ℃) and a high rate (1 C) for 300 cycles. The coulombic efficiency remains at 99.99%, and the reversible charge-discharge capacity is still 117.6 mAh g⁻¹. -1 The capacity retention rate is as high as 94%.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that only trifluoroethyl methacrylate (TFEMA) was used as the monomer; all other parameters are the same as in Example 1. The state of Comparative Example 1 after thermally initiated free radical polymerization is as follows: Figure 1 As shown in (b), since only a conventional linear polymer network was formed, no gel was prepared; instead, only a viscous, colorless, and transparent solution was obtained.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that it uses a conventional self-healing system (i.e., a deep eutectic fluorinated self-healing gel electrolyte containing UPy rigid self-healing structural units), specifically as follows: its prepolymer solution is composed of 2-ureido-4[1H]-pyrimidinone ethyl methacrylate (UPyMA), 2,2,3,3-tetrafluoropropyl methacrylate (TFM), pentaerythritol tetraacrylate (PETEA), AIBN, tetramethylurea, FEC, and LiTFSI, where UPyMA is a functional monomer, TFM is a fluorinated acrylate monomer, PETEA is a chemical crosslinking agent, AIBN is an initiator, tetramethylurea is a solvent, FEC is a functional additive, and LiTFSI is a lithium salt. Tetramethylurea, FEC, and LiTFSI together constitute the deep eutectic electrolyte solvent, the molar ratio of tetramethylurea to LiTFSI is 5:1, and FEC accounts for 20% of the total volume. UPyMA, PETEA, and AIBN accounted for 5 mol%, 0.5 mol%, and 0.5 mol% of TFM, respectively; the prepolymer solution was subjected to thermal initiation and free radical copolymerization to form a deep eutectic fluorinated self-healing polymer electrolyte.

[0070] The specific preparation method and the mechanical and self-healing properties tests of the gel electrolyte are as follows:

[0071] LiTFSI was added to tetramethylurea solvent according to the molar ratio, and 20% by volume of FEC was added. The mixture was stirred thoroughly at room temperature until completely dissolved to obtain a deep eutectic electrolyte. 5 mol% UPyMA, 0.5 mol% PETEA, and 0.5 mol% AIBN were dissolved in TFM and added to the above deep eutectic solvent at a mass ratio of 6:1. The mixture was stirred thoroughly at room temperature for 12 h until homogeneous to obtain a prepolymer solution. The prepolymer solution was thermally initiated at 70 °C for 12 h to obtain a gel polymer electrolyte. The prepolymer solution was then placed in a 70 °C oven for thermal polymerization for 12 h to obtain the deep eutectic fluorinated self-healing gel electrolyte P(UPyMA-TFM-PETEA). The experimental results described in Comparative Example 2 are as follows: Figure 2 As shown in (b), the gel electrolyte is soft and fragile and difficult to stretch to a high degree. After 6 hours of contact with the cross-section at room temperature, it still does not effectively self-repair. After stretching again, the joint of the cross-section is very easy to pull apart.

[0072] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A gel electrolyte characterized by, Prepared by free radical copolymerization of prepolymer liquid via thermal initiation, the polymer network structure of gel electrolyte is a dynamic ion-cooperative association network through component compatibility regulation mechanism. The prepolymer liquid includes hydrophilic / amphiphilic functional monomers, acrylate monomers or fluorinated acrylate monomers, initiator, and organic electrolyte. The structure of the hydrophilic / amphiphilic functional monomer is Formula I, and the structure of the acrylate monomer or fluorinated acrylate monomer is Formula II; Formula I; Formula II; In structural formula I, R1 is independently selected from H, CH3, CH2CH3, (CH2)2CH3, and the functional group M1 is independently selected from COOH, CONH2, CON(CH3)2, COO(CH3)2OH; In structural formula II, R2 is independently selected from H and CH3, and the functional group M2 is independently selected from COOCH3, COO(CH2)3CH3, COOCH2CF3, COOCH2CF2CF3, COOCH2(CF2)2H, and COOCH2CF2CFHCF3.

2. The gel electrolyte according to claim 1, characterized by, The total number of monomers accounts for 20 to 50 wt% of the mass of the prepolymer liquid, and the proportion of superior quality monomers is 30 to 40 wt%.

3. The gel electrolyte of claim 1, wherein The molar ratio of the hydrophilic / amphiphilic functional monomer to the acrylate monomer or fluorinated acrylate monomer is 1:6 to 1:1, with a preferred molar ratio of 1:5 to 1:

3.

4. The gel electrolyte of claim 1, wherein The initiator is any one of azobisisobutyronitrile (AIBN) and benzoyl peroxide, and the molar percentage of the initiator relative to the total number of monomers is 0.1 to 2.0 mol.

5. The gel electrolyte of claim 1, wherein The organic electrolyte includes a solvent, a functional additive, and a lithium salt. The solvent is a carbonate solvent or an ether solvent, and the volume ratio of the solvent to the functional additive is 7:3 to 9.5:0.

5.

6. The gel electrolyte of claim 5, wherein The carbonate solvent is one or more of ethyl methyl carbonate, methyl propionate, dimethyl carbonate, ethylene carbonate, and propylene carbonate; the ether solvent is one or more of 1,2-dimethoxyethane, hydrofluoroether, dibutyl ether, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether. The functional additive is any one of fluoroethylene carbonate, vinylene carbonate, 1,3-propanesulfonate lactone, and vinyl sulfate.

7. The gel electrolyte of claim 5, wherein The lithium salt is one or more combinations of lithium bistrifluoromethylsulfonylimide, lithium bisfluorosulfonylimide, lithium hexafluorophosphate, lithium difluoro(oxalato)borate, lithium nitrate, the total molar concentration of the lithium salt in the organic electrolyte ranges from 1 to 4 mol / L -1 .

8. The method for producing a gel electrolyte according to any one of claims 1 to 7, characterized by, Includes the following steps: A hydrophilic / amphiphilic functional monomer, an acrylate monomer or a fluorinated acrylate monomer and an initiator are introduced into an organic electrolyte and mixed and stirred at room temperature until homogeneous to obtain a prepolymer; the prepolymer is then subjected to thermally initiated free radical copolymerization to obtain a gel electrolyte; The stirring time is 1 ~ 12 h, the polymerization temperature is 50 ~ 90 o C, the polymerization time is 6 ~ 24 h.

9. A solid-state lithium battery, characterized in that, The battery includes a positive electrode, a gel electrolyte as described in any one of claims 1 to 7, and a negative electrode, wherein the gel electrolyte is a gel electrolyte prepared by thermally initiated in-situ free radical copolymerization of a prepolymer liquid within the battery.

10. The solid-state lithium battery according to claim 9, characterized in that, The pre-polymer solution is injected into the battery and left for 10 ~ 40 h, the polymerization temperature is 50 ~ 90 o C, and the polymerization time is 6 ~ 24 h.

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