A gel electrolyte and battery

Abstract

This invention provides a gel electrolyte and a battery. The gel electrolyte comprises a polymer backbone and a lithium salt. The polymer backbone includes anionic structural units, rigid backbone structural units, and crosslinked structural units. The anionic structural units include sulfonate groups, and the rigid structural units are structural units formed by the polymerization of rigid monomers, wherein the glass transition temperature of the rigid monomers is 80-180°C. The gel electrolyte provided in this application forms "mobility-restricted" fixed anionic sites by introducing anionic structural units including sulfonate groups and rigid backbone structural units as described above into the polymer backbone, thus providing a lithium salt. + Isocations provide efficient hopping conduction channels, enabling Li + The high degree of dissociation and rapid migration of the gel electrolyte simultaneously enable it to maintain both mechanical flexibility and structural stability, ensuring that the gel electrolyte retains membrane integrity during battery assembly and cycling.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a gel electrolyte and a battery. BACKGROUND

[0002] Since commercialization, lithium ion batteries have been widely used in the fields of portable electronic devices and electric vehicles. At present, a series of problems caused by liquid electrolytes, such as electrode dissolution, electrode side reactions, lithium dendrite growth and poor thermal stability, make it an urgent demand of the current market to have higher energy density, longer cycle life and higher safety of lithium ion batteries.

[0003] The gel electrolyte has both the cohesion of a solid and the diffusion transportability of a liquid, has good electrochemical stability, and the flexibility of the gel electrolyte can also ensure the wettability of the electrolyte / positive electrode interface to avoid the introduction of a large interface impedance caused by poor contact. However, gelation also brings a loss of electrolyte ionic conductivity, which reduces the electrical performance of the battery.

[0004] Therefore, it is urgent to provide a gel electrolyte with high ionic conductivity to improve the electrical performance of the battery. SUMMARY

[0005] In view of the technical problem of low ionic conductivity of the existing gel electrolyte, the application provides a gel electrolyte and a battery.

[0006] To solve the above technical problem, on the one hand, the application provides a gel electrolyte, which comprises a polymer skeleton and a lithium salt, wherein the polymer skeleton comprises anionic structural units, rigid skeleton structural units and crosslinking structural units; the anionic structural units comprise sulfonate groups, the rigid structural units are structural units formed by participation of rigid monomers in polymerization, and the glass transition temperature of the rigid monomers is 80-180℃.

[0007] Preferably, the mass ratio of the anionic structural units, the rigid skeleton structural units and the crosslinking structural units is (15-25):(40-60):(10-30).

[0008] Preferably, the anionic structural units are structural units formed by participation of anionic group-containing monomers in polymerization, and the anionic group-containing monomers comprise at least one of 2-acrylamido-2-methylpropane sulfonic acid, 2-methyl-2-acrylic acid-2-sulfonylethyl ester and p-styrene sulfonate.

[0009] Preferably, the rigid monomer comprises at least one of methyl methacrylate, styrene, isobornyl methacrylate, t-butyl methacrylate, 4-t-butyl styrene, acrylonitrile, acrylamide, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid, itaconic acid, maleic anhydride, methacrylamide, isobornyl acrylate, hydroxypivalic acid polyglycol diacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, N-isopropyl methacrylamide, N-hydroxymethyl acrylamide, N,N dimethyl acrylamide.

[0010] Preferably, the cross-linking structural unit is a structural unit formed by participation of a cross-linking monomer in polymerization, and the cross-linking monomer comprises an acrylate monomer having at least two functionalities.

[0011] Preferably, the acrylate monomer having at least two functionalities comprises at least one of polyethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, dimethylolpropanediol diacrylate, (ethoxylated)-1,6-hexanediol diacrylate, 2(propyl oxide) neopentyl glycol diacrylate, tripropyleneglycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, 4(ethoxylated) bisphenol A diacrylate, 3(ethoxylated) bisphenol A diacrylate, 10(ethoxylated) bisphenol A diacrylate, 20(ethoxylated) bisphenol A diacrylate, 30(ethoxylated) bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, 4(ethoxylated) bisphenol F diacrylate, polypropylene glycol diacrylate (Mw=400), trimethylolpropane triacrylate, 3(ethoxylated) trimethylolpropane triacrylate, 6(ethoxylated) trimethylolpropane triacrylate, 9(ethoxylated) trimethylolpropane triacrylate, 15(ethoxylated) trimethylolpropane triacrylate, (propoxylated) glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol acrylate, di(trimethylolpropane) tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate.

[0012] Preferably, the mass ratio of the polymer skeleton to the lithium salt is (65-115):(5-12).

[0013] Preferably, the liquid content ratio of the gel electrolyte after impregnation with the electrolyte is 20%-60%.

[0014] Preferably, the ionic conductivity of the gel electrolyte is greater than or equal to 3x10 -4 S·cm -1 .

[0015] In another aspect, the present application provides a battery comprising a negative electrode, a positive electrode and the gel electrolyte as described above.

[0016] The gel electrolyte provided by the present application forms "mobility-limited" fixed anion sites by introducing anionic structural units comprising sulfonate groups and rigid backbone structural units as described above into the polymer backbone, provides efficient hopping conduction channels for Li + ions, realizes high dissociation degree and fast migration of Li + ions, and at the same time makes the gel electrolyte have mechanical flexibility and structural stability, so as to ensure that the gel electrolyte maintains the integrity of the film body during battery assembly and cycling, avoids brittle fracture or collapse, and also can inhibit the volume shrinkage and solvent precipitation of the gel electrolyte, fix and connect the Li + ion conduction channels, maintain the effectiveness and continuity of the Li + ion conduction channels, and make the gel electrolyte have an electrical conductivity of 3 x 10 -4 S·cm -1 or more at 25°C. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer, the present application will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0018] An embodiment of the present application provides a gel electrolyte, which comprises a polymer backbone and a lithium salt, wherein the polymer backbone comprises anionic structural units, rigid backbone structural units and crosslinking structural units; the anionic structural units comprise sulfonate groups, the rigid structural units are structural units formed by participation of rigid monomers in polymerization, and the glass transition temperature Tg of the rigid monomers is 80-180°C.

[0019] The gel electrolyte provided by the present embodiment forms "mobility-limited" fixed anion sites by introducing anionic structural units comprising sulfonate groups and rigid backbone structural units as described above into the polymer backbone, provides efficient hopping conduction channels for Li + ions, realizes high dissociation degree and fast migration of Li + ions, and at the same time makes the gel electrolyte have mechanical flexibility and structural stability, so as to ensure that the gel electrolyte maintains the integrity of the film body during battery assembly and cycling, avoids brittle fracture or collapse, and also can inhibit the volume shrinkage and solvent precipitation of the gel electrolyte, fix and connect the Li + ion conduction channels, maintain the effectiveness and continuity of the Li + ion conduction channels, and make the gel electrolyte have an electrical conductivity of 3 x 10-4 S·cm -1 .

[0020] It can be understood that the glass transition temperature of the rigid monomer in the present application is the glass transition temperature of the homopolymer of the rigid monomer, and when the glass transition temperature Tg of the rigid monomer is 80-180℃, the structural stability of the homopolymer can be improved. The cross-linking of the rigid backbone structure unit and the cross-linking structure unit is synergistic, so that the film does not creep and does not collapse during the assembly or use of the battery, and the Li + The conduction channel has an effective conduction cross section.

[0021] In some embodiments, the mass ratio of the anion structure unit, the rigid backbone structure unit and the cross-linking structure unit is (15-25):(40-60):(10-30). By limiting the mass ratio of the anion structure unit, the rigid backbone structure unit and the cross-linking structure unit within the above range, the gel electrolyte has both mechanical flexibility and structural stability, so that the elongation at break of the wet film of the gel electrolyte is 80-120%, which avoids brittle fracture of the material and prevents the material from being too soft, so that the gel electrolyte maintains channel continuity and liquid content stability during the compression and cycle of the battery.

[0022] Specifically, the mass ratio of the anion structure unit, the rigid backbone structure unit and the cross-linking structure unit includes but is not limited to 15:40:10, 15:60:10, 15:60:30, 20:50:20, 25:40:10 or 25:60:30.

[0023] In some embodiments, the anion structure unit is a structure unit formed by polymerization of a monomer containing an anion group, and the monomer containing an anion group includes at least one of 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-methyl-2-acrylic acid-2-sulfonethyl ester, and p-styrene sulfonate. Preferably, the p-styrene sulfonate is lithium p-styrene sulfonate. By using the above polymerizable monomer containing an anion group, the sulfonate group is introduced into the polymer backbone, so that the polymer backbone forms a "limited mobility" fixed anion site, thereby providing a high-efficiency hopping conduction channel for Li + and other cations, and improving the ionic conductivity of the gel electrolyte.

[0024] The sulfonate group is a strong acid group, and the negative charge is highly delocalized on three oxygen atoms. The coordination of Li + is strong enough to form a stable "fixed anion site", but not too "tight" like the carboxylate group. + This makes Li +It is easier to dissociate from one site and complete "jump" migration by local solventization of solvent / polymer, thereby improving effective ion conduction. The resonance stability of sulfonate and lower nucleophilicity make it more resistant to oxidation, hydrolysis, and less likely to initiate side reactions or chain transfer in commonly used carbonate systems (such as EC / DEC) and common lithium salts (LiPF6, LiTFSI), thereby facilitating long-term stability of the interface and bulk phase. For high-potential cathodes (≥4.0 V), sulfonate groups generally have higher oxidative stability, which is conducive to matching "rigid monomer + crosslinking monomer" in the same system to maintain membrane integrity and cycle stability.

[0025] Compared with polydentate / multi-negative phosphates, borates, etc., sulfonates are more "reversible / easy to exchange" in coordination with Li + , and have good conductivity and mechanical integrity.

[0026] In some embodiments, the rigid monomer includes at least one of methyl methacrylate, styrene, isobornyl methacrylate, t-butyl methacrylate, 4-t-butylstyrene, acrylonitrile, acrylamide, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid, itaconic acid, maleic anhydride, methacrylamide, isobornyl acrylate, N-isopropyl methacrylamide, N-hydroxymethyl acrylamide, and N,N-dimethyl acrylamide.

[0027] In some embodiments, the crosslinking structural unit is a structural unit formed by participation of a crosslinking monomer in polymerization, and the crosslinking monomer includes at least an acrylate monomer containing two functional groups. A nanoscale free volume network is constructed by the at least acrylate monomer containing two functional groups, and is polymerized with the rigid monomer to form a polymer skeleton, so that the polymer skeleton has both mechanical flexibility and structural stability.

[0028] In some embodiments, the at least one acrylate monomer having two functionalities includes at least one of polyethylene glycol diacrylate (PEGDA), 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate (HDDA), dipropylene glycol diacrylate, diethylene glycol dimethacrylate, (ethoxylated)-1,6 hexanediol acrylate, 2(propyl oxide) neopentyl glycol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, 4(ethoxy) bisphenol A diacrylate, 3(ethoxy) bisphenol A diacrylate, 10(ethoxy) bisphenol A diacrylate, 20(ethoxy) bisphenol A diacrylate, 30(ethoxy) bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, 4(ethoxy) bisphenol F diacrylate, polypropylene glycol diacrylate PPGDA (MW = 400), trimethylolpropane triacrylate, 3(ethoxy) trimethylolpropane triacrylate, 6(ethoxy) trimethylolpropane triacrylate, 9(ethoxy) trimethylolpropane triacrylate, 15(ethoxy) trimethylolpropane triacrylate, (propoxy) glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol acrylate, di(trimethylolpropane) tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate. The polyethylene glycol diacrylate has a molecular weight ranging from 200 to 1200 g / mol. Specifically, the polyethylene glycol diacrylate is selected from polyethylene glycol diacrylate (MW = 200), polyethylene glycol diacrylate (MW = 300), polyethylene glycol diacrylate (MW = 400), polyethylene glycol diacrylate (MW = 600), polyethylene glycol diacrylate (MW = 800), polyethylene glycol diacrylate (MW = 1000), or polyethylene glycol diacrylate (MW = 1200).

[0029] In some embodiments, the lithium salt is at least one of LiPF6, LiFSI, LiBF4, LiCF3SO3, LiBETI.

[0030] In some embodiments, the mass ratio of the polymer backbone to the lithium salt is (65-115):(5-12).

[0031] Specifically, the mass ratio of the polymer backbone to the lithium salt includes, but is not limited to, 65:5, 65:9, 65:12, 90:5, 90:9, 90:12, 115:5, 115:9, or 90:12.

[0032] In some embodiments, the liquid content of the gel electrolyte after impregnated by electrolyte is 20%-60%; when the liquid content is <20%, the electrolyte in the gel electrolyte does not form a through channel, resulting in limited chain segment movement, thus leading to a decrease in ionic conductivity; and when the liquid content is >60%, the polymer skeleton is excessively diluted, the effective concentration of fixed anion sites and lithium ion transference number decrease, and the modulus of the membrane body and the interface stability deteriorate. Thus, the liquid content in the range of the present application achieves the comprehensive optimization of ionic conductivity, mechanics and safety.

[0033] In some embodiments, the ionic conductivity of the gel electrolyte is greater than or equal to 3 x 10 -4 S·cm -1 .

[0034] In the present application, the mass ratio of each structural unit is based on the mass ratio between the raw material monomers corresponding to each structural unit when participating in polymerization to obtain the multi-component copolymer.

[0035] Specifically, the preparation method of the gel electrolyte comprises the following steps:

[0036] 1. Pre-mixed solvent: mix acetone and N-methyl pyrrolidone, and blow in nitrogen to remove dissolved oxygen in the solvent.

[0037] 2. Add monomers and lithium salt: under continuous nitrogen protection, weigh the monomers containing anion groups, rigid monomers, crosslinking monomers and lithium salt into the solvent in sequence, and add a photoinitiator.

[0038] 3. Stirring and degassing: mechanically stir at 20-30°C and 300-500 rpm until the system is clear and uniform. Then connect a vacuum device to 50-100 mbar and maintain for 10-15 min to remove bubbles, to obtain a mixed solution.

[0039] 4. Base preparation: select a stainless steel plate or a polyimide film as a carrier, wipe the surface with acetone and dry in nitrogen.

[0040] 5. Coating: pour the degassed mixed solution into a coating tank, set the doctor blade height to 100-150 μm, and uniformly coat the wet film at a speed of 5-10 cm·min -1 .

[0041] 6. Primary curing pre-standing: let the wet film stand in a nitrogen tank, so that the solvent is sticky, to prevent the coating from sagging.

[0042] 7. UV crosslinking and drying: place the wet film in a UV curing box for irradiation to crosslink the monomers in the wet film, under N2 atmosphere, UV light source 365 nm, 10 mW·cm -2The crosslinked film was obtained by irradiating light for 10 min, and was left to stand at 25℃ for 30 min to release stress. The film was peeled off from the substrate and was subjected to hot air at 40℃ for 1 h to remove surface solvent. The dry film mass m1 was measured.

[0043] The wet film mass m2 after impregnation with electrolyte was measured within 1 min, and the liquid content of the gel electrolyte after impregnation with electrolyte was calculated as SR = [(m1-m2) / m2]x100%. The obtained product was a "gel electrolyte film".

[0044] Specifically, the mass ratio of the photoinitiator to the monomer forming the polymer skeleton is (0.5-1.5):(65-115); the photoinitiator includes at least one of DMPA (2,2-dimethyl-1-(4-(2-oxo-propyl)phenyl) acrylamide), Irgacure 651 (α-hydroxy ketone), Irgacure 1173 (2-hydroxy-2-methyl-1-phenylpropanone), and Irgacure TPO (phenyldimethyl dioxophosphonate); and the ultraviolet irradiation light source is selected from an ultraviolet LED (λ=365-405 nm) or a mercury lamp (λ=320-400 nm).

[0045] The one-pot random terpolymerization and one-step synthesis process of the embodiment are used to prepare the gel electrolyte film, which is compatible with coating or lamination film formation, and the process is simple. In addition, industrial monomers and low-volatile solvents are used in the preparation process, which greatly reduces the requirements for equipment and environment, and is easy to scale up and mass produce.

[0046] An embodiment of the present application provides a battery, which comprises a negative electrode, a positive electrode, and the gel electrolyte according to any one of the above embodiments.

[0047] The present application is further described below by way of examples.

[0048] The gel electrolyte and the battery thereof disclosed in the present application are specifically described.

[0049] Example 1

[0050] Gel electrolyte

[0051] Acetone and NMP were mixed and purged with nitrogen for 15 min to remove dissolved oxygen in the solvent. Under continuous nitrogen protection, 20 parts of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 55 parts of methyl methacrylate (MMA), 25 parts of PEGDA (MW=800), and 8 parts of LiTFSI were weighed into the solvent in sequence, and 1 part of the photoinitiator DMPA was added. Then, mechanical stirring was performed at 25°C and 400 rpm for 30 min until the system was clear and uniform, a vacuum device was connected to 75 mbar, and the system was kept for 13 min to remove bubbles, to obtain a mixed solution.

[0052] The mixed solution was blade-coated on a plasma-cleaned stainless steel plate or a PTFE plate, with a wet film thickness of 120-150 µm. The film was photocured under an N2 atmosphere at 365 nm, 10 mW·cm -2 , for 10 min to obtain a crosslinked film; the film was left to stand at 25°C for 30 min to relieve stress. After the film was peeled off from the substrate, surface solvent was removed by hot air at 40°C for 1 h. The film was immersed in an electrolyte (EC:DEC=1:1, 1.0M LiPF6) for 2 h, taken out, and the surface liquid was scraped off; the film was gently touched with filter paper for 10 s, to obtain a “gel electrolyte film”.

[0053] Preparation of a negative electrode sheet

[0054] Graphite (active material), a conductive agent, and PAA (water-soluble polyacrylic acid) were mixed in a mass ratio of 95:2:3, and deionized water was added to prepare a negative electrode slurry. The negative electrode slurry was coated on a copper foil, and the copper foil was dried to obtain a negative electrode sheet.

[0055] Preparation of a positive electrode sheet

[0056] LiFePO4 (active material), a conductive agent (carbon black / CNT), and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 95:2:3, and NMP was added to prepare a positive electrode slurry. The positive electrode slurry was coated on an aluminum foil, and the aluminum foil was dried to obtain a positive electrode sheet.

[0057] Preparation of a battery

[0058] The negative electrode sheet, the positive electrode sheet, and the gel electrolyte were assembled into a battery.

[0059] Examples 2-16

[0060] Examples 2-16 and most of the steps of Example 1 are the same, except that the formulations in Table 1 were used.

[0061] Comparative Example 1

[0062] Most of the steps of Comparative Example 1 and Example 1 are the same, except that the film was not immersed in the electrolyte for infiltration.

[0063] Comparative Example 2

[0064] Comparative Example 2 and Example 1 are mostly the same except that the electrolyte in the electrolyte impregnation step does not contain LiPF6.

[0065] Comparative Examples 3-7

[0066] Comparative Examples 3-7 and Example 1 are mostly the same except that the formulations in Table 1 are used.

[0067] Table 1

[0068]

[0069] Electrical performance testing: All EIS (electrochemical impedance spectroscopy) cycle tests were performed within 1 h after impregnation. No high vacuum or long drying was performed to maintain the gel state, unless otherwise stated.

[0070] The gel electrolytes and batteries prepared in the above examples and comparative examples were tested as follows.

[0071] 1. Ionic conductivity: The gel electrolyte membrane was cut into a sample with a diameter of 10 mm; the thickness (L) of three different points was measured using a micrometer, and the diameter was measured using a caliper, and the effective area A = π (d / 2) was converted. 2 An unreactive Pt sheet was used as the blocking electrode, and two pieces of 100-μm-thick Pt sheet electrodes were used. One Pt sheet electrode was placed in the 2032 Coin-cell fixture base, and then placed in the sample disc, and the second Pt sheet electrode was placed on top, and gently corrected for centering. The nut was tightened or a spring was installed to ensure uniform pressure between the electrodes and the sample (typical pressure of 10-20 MPa). The assembled fixture was placed in a 25 °C constant temperature oven, preheated to the target temperature and equilibrated for 30 min or more. Then the EIS measurement was started, the alternating current voltage amplitude was set to 5-10 mV (rms), the frequency range was 10 MHz ~10 mHz, the number of scanning points was at least 50 frequency points, and the low frequency was sampled more. Scan and repeat the measurement three times, and take the average value.

[0072] 2. Test of mechanical properties: The sample was prepared according to the national standard GB / T 528 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", and the sample was cut into a 1A dumbbell-shaped test sample (test length 20.0±0.5mm, thickness 2.0±0.2mm) after drying at 40℃ for 1h, and the electronic tensile testing machine was used at a rate of 50mm / min (Dongguan Dazhong Instrument Co., Ltd., Model DZ 101) to test the elongation at break, and the tensile test was carried out in a constant temperature and humidity chamber (23±2℃, 50±5%RH).

[0073] 3. Electrical performance test: at 25℃, 0.5 C to 4.0V, cut-off current is 0.05C, discharge to 3.0V at 1C, record the capacity retention rate under the cycle condition of 300 cycles.

[0074] The test results are shown in Table 2 below.

[0075] Table 2

[0076]

[0077] It can be seen from the test results of the above examples and Comparative Examples 1 and 2 that the gel electrolyte provided by the present application has excellent ionic conductivity and elongation at break after being impregnated with the electrolyte containing lithium salt, and can effectively improve the cycle capacity retention rate of the solid-state battery.

[0078] It can be seen from the test results in Table 2 that the introduction of the anion structural unit can improve the ionic conductivity of the gel electrolyte, the introduction of the rigid backbone structural unit can improve the elongation at break of the gel electrolyte, and the introduction of the cross-linking structural unit makes the cross-linking network exist in the gel electrolyte, thereby improving the electrolyte swelling resistance of the gel electrolyte and improving the cycle performance. The gel electrolyte in the comparative example does not contain the cross-linking structural unit, and is easy to swell in the electrolyte, has poor size / interface stability, and leads to poor cycle performance. Furthermore, it can be further concluded from the test results of Examples 1-13 that when the mass ratio of the anion structural unit, the rigid backbone structural unit and the cross-linking structural unit is in the range of (15-25):(40-60):(10-30), the gel electrolyte has good ionic conductivity, elongation at break and capacity retention rate.

[0079] It can be seen from the test results of Examples 1, 14-16, Comparative Examples 4 and 5 that when the glass transition temperature of the homopolymer formed by the rigid monomer decreases, the elongation at break of the gel electrolyte decreases, and when the glass transition temperature of the homopolymer formed by the rigid monomer increases, the elongation at break of the gel electrolyte increases, but when the glass transition temperature of the homopolymer formed by the rigid monomer is too high, the elongation at break of the gel electrolyte decreases.

[0080] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gel electrolyte characterized by, The gel electrolyte comprises a polymer skeleton and a lithium salt, the polymer skeleton is a multi-copolymer, the polymer skeleton comprises an anionic structural unit, a rigid skeleton structural unit and a crosslinking structural unit; the anionic structural unit comprises a sulfonate group, the rigid skeleton structural unit is a structural unit formed by polymerization of a rigid monomer, and the glass transition temperature of the rigid monomer is 80-180℃; The mass ratio of the anionic structural unit, the rigid skeleton structural unit and the crosslinking structural unit is (15-25):(40-60):(10-30); The crosslinking structural unit is a structural unit formed by polymerization of a crosslinking monomer, and the crosslinking monomer comprises an acrylate monomer with at least two functionalities; The liquid content rate of the gel electrolyte after being impregnated with an electrolyte is 20%-60%.

2. The gel electrolyte according to claim 1, characterized by, The anionic structural unit is a structural unit formed by polymerization of a monomer containing an anion group, and the monomer containing an anion group comprises at least one of 2-acrylamido-2-methylpropanesulfonic acid, 2-methyl-2-acrylic acid-2-sulfonylethyl ester and p-styrenesulfonate.

3. The gel electrolyte according to claim 2, characterized by, The rigid monomer comprises at least one of methyl methacrylate, styrene, isobornyl methacrylate, tert-butyl methacrylate, 4-tert-butylstyrene, acrylonitrile, acrylamide, cyclohexyl methacrylate, benzyl methacrylate, itaconic acid, maleic anhydride, methacrylamide, isobornyl acrylate, hydroxypivalic acid polyglycol diacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, N-isopropyl methacrylamide, N-hydroxymethyl acrylamide and N,N dimethyl acrylamide.

4. The gel electrolyte of claim 1, wherein The acrylate monomer with at least two functionalities comprises at least one of polyethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, dimethylolpropanediol diacrylate, (ethoxylated)-1,6-hexanediol diacrylate, 2(propyl oxide) neopentyl glycol diacrylate, tripropyleneglycol diacrylate, triethylene glycol diacrylate, 4(ethoxylated) bisphenol A diacrylate, 3(ethoxylated) bisphenol A diacrylate, 10(ethoxylated) bisphenol A diacrylate, 20(ethoxylated) bisphenol A diacrylate, 30(ethoxylated) bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, 4(ethoxylated) bisphenol F diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, 3(ethoxylated) trimethylolpropane triacrylate, 6(ethoxylated) trimethylolpropane triacrylate, 9(ethoxylated) trimethylolpropane triacrylate, 15(ethoxylated) trimethylolpropane triacrylate, (propoxylated) glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol acrylate, di(trimethylolpropane) tetraacrylate, bis-pentaerythritol pentaacrylate and bis-pentaerythritol hexaacrylate.

5. The gel electrolyte of claim 1, wherein The mass ratio of the polymer skeleton to the lithium salt is (65-115):(5-12).

6. The gel electrolyte of claim 1, wherein The ionic conductivity of the gel electrolyte is greater than or equal to 3 x 10 -4 S·cm -1 .

7. A battery, characterized by A gel electrolyte including any one of claims 1 to 6.

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