Solid electrolyte, secondary battery, and electric device

Abstract

The invention discloses a solid electrolyte, a secondary battery and an electric device, and belongs to the technical field of batteries, the solid electrolyte comprises a polymer solid electrolyte, a lithium salt and a cross-linked copolymer; the cross-linked copolymer comprises a polymer solid electrolyte containing a carbon-carbon double bond and bis (10-undecylene-1-yl) malonate grafted fullerene. The solid electrolyte can effectively improve the transference number of lithium ions, improve the mechanical property of the solid electrolyte and effectively prolong the cycle life of a secondary battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a solid-state electrolyte, a secondary battery and an electric device. BACKGROUND

[0002] From mobile phones to electric vehicles, secondary batteries (especially lithium ion batteries) have penetrated into people's lives, but the energy density of existing liquid secondary batteries still cannot meet people's needs.

[0003] Solid-state batteries have higher energy density and safety, among which the positive electrode material of lithium metal solid-state batteries can use sulfur-containing solid-state electrolyte or existing positive electrode material, so as to realize higher energy density of the battery, but the lithium metal of the lithium metal battery has problems such as high chemical instability, uneven lithium deposition and uncontrollable dendrite growth.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies in the prior art and provide a solid-state electrolyte, a secondary battery and an electric device, which can effectively improve the lithium ion migration number and improve the mechanical properties of the solid-state electrolyte, and effectively improve the cycle life of the secondary battery.

[0006] To achieve the above purpose, the first aspect of the present application provides a solid-state electrolyte, comprising a polymer solid-state electrolyte, a lithium salt and a cross-linked copolymer; the cross-linked copolymer comprises a polymer solid-state electrolyte containing carbon-carbon double bond and propandioic acid di(10-undecen-1-yl) ester grafted fullerene.

[0007] As an embodiment of the present application, at least one of the following (I) ~ (III) is satisfied: (I) The mass percentage content of the polymer solid-state electrolyte in the solid-state electrolyte is 18 ~ 26%; (II) The mass percentage content of the lithium salt in the solid-state electrolyte is 31 ~ 38%; (III) The mass percentage content of the cross-linked copolymer in the solid-state electrolyte is 45 ~ 52%.

[0008] As an embodiment of the present application, the mass percentage content of the polymer solid-state electrolyte containing carbon-carbon double bond in the cross-linked copolymer is 60 ~ 72%; and / or The mass percentage content of the propandioic acid di(10-undecen-1-yl) ester grafted fullerene in the cross-linked copolymer is 28 ~ 40%.

[0009] As an embodiment of the present application, the grafting rate of the malonic acid di(10-undecen-1-yl) ester in the malonic acid di(10-undecen-1-yl) ester grafted fullerene is 62-77%.

[0010] As an embodiment of the present application, the weight average molecular weight of the polymer solid electrolyte containing carbon-carbon double bond is 400-1050; and / or The weight average molecular weight of the polymer solid electrolyte is 400-1050.

[0011] As an embodiment of the present application, the polymer solid electrolyte contains at least one of the following: polyethylene oxide containing carbon-carbon double bond, polyvinyl alcohol containing carbon-carbon double bond, polyvinylidene fluoride containing carbon-carbon double bond.

[0012] As an embodiment of the present application, the polymer solid electrolyte contains at least one of the following: polyethylene oxide, polyvinylpyrrolidone, polyvinylidene fluoride, polyacrylonitrile, polyethylene glycol, polyethylene glycol dimethyl ether.

[0013] As an embodiment of the present application, the lithium salt contains at least one of the following: LiTFSI, LiPF6, LiFSI, LiClO4, LiBTFSI, LiTPBTFSI, LiDFP, LiDFTFSI, LiFTFSI.

[0014] The second aspect of the present application provides a secondary battery containing the above-mentioned solid electrolyte.

[0015] The third aspect of the present application provides an electric device containing the above-mentioned secondary battery as a power supply of the electric device.

[0016] The beneficial effects of the present application are as follows: the solid electrolyte contains a polymer solid electrolyte, a lithium salt and a crosslinked copolymer, the crosslinked copolymer contains a polymer solid electrolyte containing carbon-carbon double bond and a malonic acid di(10-undecen-1-yl) ester grafted fullerene, the crosslinked copolymer can provide a certain active material expansion space, improve the stability of the solid electrolyte, avoid the crystallization of the polymer solid electrolyte, effectively improve the transmission efficiency of lithium ions, the malonic acid di(10-undecen-1-yl) ester grafted fullerene can absorb free radicals generated in the cycle process of the secondary battery, effectively improve the lithium ion migration number, and improve the mechanical properties of the solid electrolyte, effectively improve the cycle life of the secondary battery. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The malonic acid di(10-undecen-1-yl) ester grafted fullerene prepared in Example 1 is analyzed by 13 C NMR spectrum. DETAILED DESCRIPTION

[0018] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0019] In the present application, the technical features described in an open way include both the closed technical solutions consisting of the listed features and the open technical solutions containing the listed features.

[0020] In the present application, if no special description is made, the numerical range is regarded as continuous and includes the minimum value and the maximum value of the range and each value between the minimum value and the maximum value. Further, when the range refers to an integer, each integer between the minimum value and the maximum value of the range is included. In addition, when multiple ranges are provided to describe a feature or a characteristic, the ranges can be combined. In other words, unless otherwise specified, all the ranges disclosed herein should be understood to include any and all sub-ranges.

[0021] The inventors of the present application have found that the current polymer solid-state electrolyte (for example, PEO, polyethylene oxide) can effectively solve the problems of high chemical instability of lithium metal and uncontrollable lithium deposition and dendrite growth, but the PEO solid-state electrolyte is easy to crystallize. In the prior art, the crystallinity is reduced by copolymerization, for example, PS (polystyrene) and PEO are copolymerized. PS provides mechanical strength and balances the ion conduction and mechanical strength well at high temperature, but the effect is poor at low temperature. In the prior art, short-chain PEO is used as a monomer to prepare a mixed graft block copolymer (mGBCP). The short-chain PEO with high freedom can help the migration of lithium ions, but the mechanical strength of the mixed graft block copolymer (mGBCP) is very low, which affects the long-term cycle performance of the secondary battery.

[0022] Therefore, based on the above problems, the embodiments of the present application provide a solid-state electrolyte, which comprises a polymer solid-state electrolyte, a lithium salt and a cross-linked copolymer; the cross-linked copolymer comprises a polymer solid-state electrolyte containing a carbon-carbon double bond and a propandioic acid di(10-undecen-1-yl) ester grafted fullerene.

[0023] The solid-state electrolyte described in the application comprises a polymer solid-state electrolyte, a lithium salt and a cross-linked copolymer, the cross-linked copolymer comprises a polymer solid-state electrolyte containing a carbon-carbon double bond and a propandioic acid di(10-undecen-1-yl) ester grafted fullerene, the cross-linked copolymer can provide a certain active material expansion space, improve the stability of the solid-state electrolyte, and avoid the crystallization of the polymer solid-state electrolyte, the polymer solid-state electrolyte containing a carbon-carbon double bond and the propandioic acid di(10-undecen-1-yl) ester grafted fullerene together provide chain rotation for the transmission of lithium ions, effectively improve the transmission efficiency of lithium ions, the propandioic acid di(10-undecen-1-yl) ester grafted fullerene can absorb free radicals generated in the secondary battery cycle process, while effectively improving the lithium ion migration number and improving the mechanical properties of the solid-state electrolyte, under the joint action of the polymer solid-state electrolyte, the lithium salt and the cross-linked copolymer, the cycle life of the secondary battery is effectively improved.

[0024] In some embodiments, the mass percentage of the polymer solid-state electrolyte in the solid-state electrolyte is 18-26%, for example, it can be 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26% or a range composed of any two of the above values, by controlling the mass percentage of the polymer solid-state electrolyte in this range, the transmission performance of lithium ions can be effectively improved, and the mechanical strength and structural stability of the solid-state electrolyte are improved.

[0025] In some embodiments, the mass percentage of the lithium salt in the solid-state electrolyte is 19-30%, for example, it can be 19%, 20%, 23%, 25%, 26%, 27%, 28%, 30% or a range composed of any two of the above values, by controlling the mass percentage of the lithium salt in the solid-state electrolyte in this range, the lithium ion conductivity, the mechanical strength and the reduction of lithium precipitation phenomenon can be improved.

[0026] In some embodiments, the mass percentage of the cross-linked copolymer in the solid-state electrolyte is 45-52%, for example, it can be 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52% or a range composed of any two of the above values, by controlling the mass percentage of the cross-linked copolymer in the solid-state electrolyte in this range, the Young's modulus of the solid-state electrolyte can be effectively improved, the ion conductivity and the stability of the solid-state electrolyte are improved, the occurrence of side reactions in the cycle process is reduced, and the cycle life of the secondary battery is effectively improved.

[0027] In some embodiments, the content of the polymer containing carbon-carbon double bond in the cross-linked copolymer is 60-72%, for example, 60%, 62%, 64%, 65%, 66%, 68%, 70%, 72%, or a range between any two of the above values. By controlling the content of the polymer containing carbon-carbon double bond in the cross-linked copolymer in the above range, the mechanical strength and the segment activity of the electrolyte can be balanced, the lithium ion conductivity can be effectively improved, the lithium precipitation can be improved, and the cycle performance can be effectively improved. In some embodiments, the synthesis of the di(10-undecen-1-yl) malonate is as follows: 9-11 parts by mass of malonyl chloride and 11-13 parts by mass of pyridine are added to 55-65 parts by mass of malonyl chloride, and stirred to obtain solution A; 26-28 parts by mass of 3-chloropropanol is added to 59-61 parts by mass of dichloromethane to obtain solution B, and solution B is added to solution A, and the mixture is reacted at -5-5°C for 1-2 hours. The solvent is removed by silica gel column chromatography and rotary evaporation to obtain di(10-undecen-1-yl) malonate. In some embodiments, the content of the di(10-undecen-1-yl) malonate grafted fullerene in the cross-linked copolymer is 28-40%, for example, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, or a range between any two of the above values. By controlling the content of the di(10-undecen-1-yl) malonate grafted fullerene in the cross-linked copolymer in the above range, more cross-linking active sites can be provided, the cross-linking density can be increased, the Young's modulus of the solid-state electrolyte can be increased, the attraction effect of the negative ions in the system can be improved, the movement of the negative ions can be limited, thereby increasing the number of positively charged lithium ions, and the stability of the solid-state electrolyte can be improved by the antioxidant effect of the fullerene.

[0028] In some embodiments, the grafting rate of the di(10-undecen-1-yl) malonate in the di(10-undecen-1-yl) malonate grafted fullerene is 62-77%, for example, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 77%, or a range between any two of the above values.

[0029] In some embodiments, the weight average molecular weight of the polymer solid electrolyte containing carbon-carbon double bond is 400-1050, for example, 400, 500, 600, 700, 800, 900, 1000, 1050 or a range between any two of the numbers. By controlling the weight average molecular weight of the polymer solid electrolyte containing carbon-carbon double bond in this range, the polymer solid electrolyte containing carbon-carbon double bond has a suitable crystal region, effectively balances the mechanical properties and ionic conductivity, avoids excessive crystal region in the polymer solid electrolyte containing carbon-carbon double bond, thereby avoiding the reduction of ionic conductivity, effectively reducing the occurrence of side reactions, and effectively improving the cycle life of the secondary battery.

[0030] In some embodiments, the weight average molecular weight of the polymer solid electrolyte is 450-950, for example, 450, 500, 550, 650, 700, 750, 800, 950, 900, 950 or a range between any two of the numbers. By controlling the weight average molecular weight of the polymer solid electrolyte in this range, the crystallinity can be effectively reduced, the lithium ion migration efficiency can be improved, and the cycle life of the secondary battery at low temperature can be improved.

[0031] In some embodiments, the polymer solid electrolyte contains at least one of polyethylene oxide containing carbon-carbon double bond, polyvinyl alcohol containing carbon-carbon double bond, and polyvinylidene fluoride containing carbon-carbon double bond.

[0032] In some embodiments, the polymer solid electrolyte contains at least one of polyethylene oxide containing carbon-carbon double bond, polyvinyl alcohol containing carbon-carbon double bond, and polyvinylidene fluoride containing carbon-carbon double bond.

[0033] The preparation of polyethylene oxide containing carbon-carbon double bond is exemplarily described below.

[0034] The preparation method of the polyethylene oxide containing carbon-carbon double bond comprises the following steps: Acrylic acid, polyethylene oxide, and 4-dimethylaminopyridine are added to dichloromethane, stirred uniformly, carbonic acid diisopropyl ester is added, reacted, washed with saturated brine, dried, and fast chromatography is performed on a silica gel column. The solvent is removed by rotary evaporation to obtain polyethylene oxide containing carbon-carbon double bond.

[0035] In some embodiments, the temperature of the reaction is 18-30℃, for example, 18℃, 20℃, 22℃, 25℃, 28℃, 30℃ or a range between any two of the numbers.

[0036] In some embodiments, the reaction time is 18-36 h, for example, it can be 18 h, 20 h, 24 h, 30 h, 32 h, 36 h or a range defined by any two of the numbers. In some embodiments, the mass ratio of the acrylic acid, polyethylene oxide, 4-dimethylamino pyridine, dichloromethane, and diisopropyl carbonate is (11-13): 100: (3-5): (24-26). In some embodiments, the polymer solid-state electrolyte comprises at least one of polyethylene oxide, polyvinylpyrrolidone, polyvinylidene fluoride, polyacrylonitrile, polyethylene glycol, and polyethylene glycol dimethyl ether.

[0037] In some embodiments, the polymer solid-state electrolyte comprises at least one of polyethylene oxide, polyvinylidene fluoride, and polyethylene glycol.

[0038] In some embodiments, the lithium salt comprises at least one of LiTFSI (lithium bis-trifluoromethanesulfonimide), LiPF6 (lithium hexafluorophosphate), LiFSI (lithium bis-fluorosulfonimide), LiClO4 (lithium perchlorate), LiBTFSI (lithium benzene sulfonyl (trifluoromethylsulfonyl) imide), LiTPBTFSI (lithium 2,4,6-triisopropyl benzene sulfonyl (trifluoromethylsulfonyl) imide), LiDFP (lithium difluorophosphate), LiDFTFSI (lithium difluoromethylsulfonyl (trifluoromethylsulfonyl) imide), and LiFTFSI (lithium acetyl sulfonimide).

[0039] In some embodiments, the fullerene comprises at least one of C60, C70, and C240.

[0040] In some embodiments, the preparation method of the solid-state electrolyte is as follows: The polymer solid-state electrolyte containing carbon-carbon double bond, malonic acid di(10-undecen-1-yl) ester grafted fullerene, lithium salt, polymer solid-state electrolyte, and photoinitiator are added into a solvent, stirred uniformly to obtain a slurry; the slurry is coated on a substrate, dried, and irradiated with ultraviolet light to obtain a solid-state electrolyte.

[0041] In some embodiments, the photoinitiator comprises at least one of photoinitiator 2959, photoinitiator 184, photoinitiator 819, photoinitiator 1173, and photoinitiator TPO.

[0042] In some embodiments, the photoinitiator is 0.4-0.8% of the total mass of the polymer solid-state electrolyte containing carbon-carbon double bond and malonic acid di(10-undecen-1-yl) ester grafted fullerene, for example, it can be 0.4%, 0.5%, 0.6%, 0.7%, 0.8% or a range defined by any two of the numbers.

[0043] In some embodiments, the mass ratio of the carbon-carbon double bond-containing polymer, the malonic acid di(10-undecen-1-yl) ester grafted fullerene, the lithium salt, and the polymer solid-state electrolyte is (27-38), (15-21), (19-30):(18-26).

[0044] In some embodiments, the solvent includes at least one of tetrahydrofuran, acetone, methanol, ethanol, N,N-dimethylformamide, acetonitrile, dimethyl sulfoxide, sulfolane, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene nitrate, ethylene carbonate, acetone, 1,4-butyrolactone, and dimethylacetamide.

[0045] In some embodiments, the substrate includes at least one of a copper foil, an aluminum foil, a carbon cloth, a carbon paper, and stainless steel.

[0046] In some embodiments, the ultraviolet light irradiation time is 0.5-10 h, for example, 0.5 h, 1 h, 2 h, 4 h, 5 h, 6 h, 8 h, 10 h, or a range defined by any two of the above values.

[0047] In some embodiments, the malonic acid di(10-undecen-1-yl) ester grafted fullerene is prepared by the following method: The malonic acid di(10-undecen-1-yl) ester, the fullerene, and carbon tetrachloride are dissolved in a solvent, a catalyst is added, and the reaction is performed to obtain the malonic acid di(10-undecen-1-yl) ester grafted fullerene.

[0048] In some embodiments, the mass ratio of the malonic acid di(10-undecen-1-yl) ester, the carbon tetrachloride, and the fullerene is (2-7):(9-25):1.

[0049] In some embodiments, the catalyst includes 1,8-diazabicyclo.

[0050] In some embodiments, the mass ratio of the fullerene and the catalyst is 1:(1-5).

[0051] In some embodiments, the reaction temperature is -2-2℃, and the reaction time is 2-10 h.

[0052] In some embodiments, after the reaction, the method further includes silica gel column purification, and the silica gel column is eluted with a mixture of toluene and dichloromethane.

[0053] An embodiment of the present application provides a secondary battery including the solid-state electrolyte described above.

[0054] In some embodiments, the solid electrolyte exists in the secondary battery in the form of a membrane and is located between the positive and negative electrodes.

[0055] In some embodiments, the secondary battery includes a positive electrode sheet, the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer including a positive active material.

[0056] In some embodiments, the positive electrode active material may be a positive electrode active material known in the art for use in secondary batteries.

[0057] As a non-limiting example, when the secondary battery is a lithium-ion battery, the positive electrode active material may include lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials or substances, and other conventional materials or substances that can be used as positive electrode active materials for secondary batteries may also be used. These positive electrode active substances may be used alone or in combination of two or more. Among them, non-limiting examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds.

[0058] As a non-limiting example, when the secondary battery is a sodium-ion battery, the positive electrode active material may be selected from at least one of sodium-iron composite oxide, sodium-cobalt composite oxide, sodium-manganese composite oxide, sodium-nickel composite oxide, sodium-nickel-titanium composite oxide, sodium-nickel-manganese composite oxide, sodium-iron-manganese composite oxide, sodium-nickel-cobalt-manganese composite oxide, sodium-iron phosphate compound, sodium-manganese phosphate compound, and sodium-cobalt phosphate compound.

[0059] In some embodiments, the positive electrode active material layer may include the solid electrolyte described above.

[0060] In some of these embodiments, the type of positive current collector is not particularly limited, and it may be any material known to be suitable for use as a positive current collector.

[0061] In some embodiments, the positive current collector includes metallic materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, as well as carbon materials such as carbon cloth and carbon paper.

[0062] There are no particular restrictions on the form of the positive electrode current collector. When the positive electrode current collector is a metallic material, it can be in the form of metal foil, metal cylinder, metal strip, metal plate, metal foil, metal mesh, stamped metal, foamed metal, etc. When the positive electrode current collector is a carbon material, it can be in the form of carbon plate, carbon film, carbon cylinder, etc.

[0063] In some embodiments, the positive electrode active material layer further includes a conductive agent and a positive electrode binder.

[0064] In some embodiments, the secondary battery further includes a negative electrode tab including a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material.

[0065] In the present application, the negative electrode current collector is not particularly limited as long as the object of the present application can be achieved, and for example, can be a copper foil, a copper alloy foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, or a composite current collector.

[0066] In some embodiments, the negative electrode active material includes at least one of graphite, a silicon-based material, meso-carbon microbeads (MCMB), hard carbon, soft carbon, a Li-Sn alloy, a Li-Sn-O alloy, Sn, SnO, SnO2, a spinel-structured lithium titanate Li4Ti5O12, a Li-Al alloy, and metallic lithium. 12

[0067] In some embodiments, the negative electrode active material layer further includes a conductive agent and a negative electrode binder.

[0068] In some embodiments, the type of the conductive agent mentioned in the present application is not limited, and a known conductive agent can be used.

[0069] In some embodiments, the conductive agent includes at least one of acetylene black, needle coke, a carbon nanotube, graphene, or the like.

[0070] In some embodiments, the type of the binder mentioned in the present application is not limited, and a known binder can be used.

[0071] In some embodiments, the positive electrode binder and the negative electrode binder each independently include at least one of polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, an aromatic polyamide, cellulose, cellulose nitrate, butadiene-styrene rubber, nitrile rubber, fluoro rubber, isoprene rubber, polybutadiene rubber, ethylene-propylene rubber, a styrene-butadiene-styrene block copolymer or a hydrogenated product thereof, an ethylene-propylene-diene terpolymer, a styrene-ethylene-butadiene-ethylene copolymer, a styrene-isoprene-styrene block copolymer, syndiotactic-1,2-polybutadiene, polyvinyl acetate, an ethylene-vinyl acetate copolymer, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and a polytetrafluoroethylene-ethylene copolymer.

[0072] ​In some embodiments, the secondary battery can include an outer package that can be used to encapsulate the electrode assembly and the electrolyte.

[0073] In some embodiments, the outer package of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like. The outer package of the secondary battery can also be a soft package, such as a pouch-type soft package. The soft package can be made of plastic, and as plastic, polypropylene, polybutylene terephthalate, polybutylene succinate, or the like can be listed.

[0074] The shape of the secondary battery is not particularly limited in the present application, and the secondary battery can be cylindrical, square, or any other arbitrary shape.

[0075] An embodiment of the present application provides an electric device including the secondary battery described above as a power supply for the electric device.

[0076] For example, the electric device described above can include a mobile device (such as a mobile phone, a notebook computer, or the like), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, or the like), an electric train, a ship, a satellite, an energy storage system, or the like, but is not limited thereto.

[0077] The present application is further described below with specific examples: Example 1 A method for preparing a solid-state electrolyte includes the following steps: (1) Preparation of propionic acid di(10-undecen-1-yl) ester grafted fullerene: 10.00 parts by mass of malonyl chloride was dissolved in 60.00 parts by mass of dichloromethane and 12.35 parts by mass of pyridine was added, and stirred to obtain solution A. 26.58 parts by mass of undecenol was dissolved in 60.00 parts by mass of dichloromethane to obtain solution B. Solution B was added dropwise to solution A, and reacted at 0°C for 2 hours. After that, fast chromatography was performed on a silica gel column, and rotary evaporation was performed to obtain propionic acid di(10-undecen-1-yl) ester.

[0078] 5.7 parts by mass of 2yne (hereinafter referred to as propionic acid di(10-undecen-1-yl) ester), 23 parts by mass of CBr4, and 1 part of fullerene C60 were dissolved in o-dichlorobenzene solution, and stirred for 30 minutes to fully dissolve. Then, 3.2 parts of catalyst DBU was added at 0°C. After reacting for 4 hours, the insoluble matter was first filtered, and then purified on a silica gel column. Toluene and dichloromethane (volume ratio 1:1) were used as eluent to elute the silica gel column. The eluate was collected, concentrated, and then precipitated in methanol three times. After rotary evaporation, propionic acid di(10-undecen-1-yl) ester grafted fullerene was obtained.

[0079] As shown in Figure 1 malonate di(10-undecen-1-yl) ester grafted fullerene was tested 13 C NMR, as shown in Figure 1 malonate di(10-undecen-1-yl) ester peak appeared, indicating that the chemical grafting was successful. (2) Preparation of solid-state electrolyte: Preparation of vinyl-modified PEO: 11.53 parts by mass of acrylic acid, 100.00 parts by mass of PEO (polyethylene oxide), 3.26 parts by mass of 4-dimethylaminopyridine were added to 90.00 parts by mass of dichloromethane in a round-bottom flask, and then 25.34 parts by mass of diisopropyl carbonate was added dropwise. After stirring uniformly, the mixture was reacted at 0°C for 24 hours, washed with saturated brine three times, dried with anhydrous sodium sulfate, purified by silica gel column chromatography, and the solvent was removed to obtain the product.

[0080] 22 parts by mass of malonate di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of vinyl-modified PEO (weight average molecular weight 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 were dissolved in THF, stirred uniformly, coated on a copper foil, dried at 55°C for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0081] The parameters of the solid-state electrolyte are shown in Table 1.

[0082] Example 2 Example 2 differs from Example 1 in that an equal amount of fullerene C70 is used to replace fullerene C60.

[0083] Examples 3-7 Examples 3-7 differ from Example 1 in that the composition of the solid-state electrolyte is changed by changing the amount of raw materials added in step (2).

[0084] The preparation method of the solid-state electrolyte of Example 3 comprises the following steps: (1) Preparation of malonate di(10-undecen-1-yl) ester grafted fullerene: 5.7 parts by mass of 2yne, 23 parts by mass of CBr4 and 1 part of fullerene C60 were dissolved in o-dichlorobenzene solution, stirred for 30 minutes to dissolve completely, then 3.2 parts of catalyst DBU was added at 0°C. After reacting for 4 hours, the insoluble material was first filtered, then purified by silica gel column, toluene and dichloromethane (volume ratio 1:1) were used as eluent to elute the silica gel column, the eluate was collected, concentrated, precipitated with methanol three times, and then dried by rotary evaporator to obtain malonate di(10-undecen-1-yl) ester grafted fullerene.

[0085] (2) Preparation of solid-state electrolyte: 22 parts by mass of malonic acid di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of polyethylene oxide (vinyl-modified PEO, weight average molecular weight 750), 49.3 parts of vinyl-modified PEO (weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 were dissolved in THF, stirred uniformly, coated on a copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0086] The parameters of the solid-state electrolyte are shown in Table 1.

[0087] The preparation method of the solid-state electrolyte of Example 4 includes the following steps: (1) Preparation of malonic acid di(10-undecen-1-yl) ester grafted fullerene: 5.7 parts by mass of 2yne, 23 parts by mass of CBr4 and 1 part of fullerene C60 were dissolved in o-dichlorobenzene solution, stirred for 30 minutes to dissolve completely, and then 3.2 parts of catalyst DBU was added at 0 degrees. After 4 hours of reaction, the insoluble matter was first filtered, and then purified on a silica gel column. Toluene and dichloromethane (volume ratio 1:1) were used as eluent to elute the silica gel column, and the eluate was collected. The eluate was concentrated and then precipitated with methanol three times. After drying with a rotary evaporator, malonic acid di(10-undecen-1-yl) ester grafted fullerene was obtained.

[0088] (2) Preparation of solid-state electrolyte: 22 parts by mass of malonic acid di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of polyethylene oxide (vinyl-modified PEO, weight average molecular weight 750), 46.2 parts of vinyl-modified PEO (weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 were dissolved in THF, stirred uniformly, coated on a copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0089] The parameters of the solid-state electrolyte are shown in Table 1.

[0090] The preparation method of the solid-state electrolyte of Example 5 includes the following steps: (1) Preparation of malonic acid di(10-undecen-1-yl) ester grafted fullerene: Dissolve 5.7 parts by mass of 2yne, 23 parts by mass of CBr4, and 1 part of fullerene C60 in an o-dichlorobenzene solution, fully dissolve after stirring for 30 minutes, add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, then spin dry with a rotary evaporator to obtain di(10-undecen-1-yl) ester grafted fullerene.

[0091] (2) Preparation of solid electrolyte: Dissolve 22 parts by mass of di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of vinyl modified PEO (weight average molecular weight 750), 43.3 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI, and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0092] Among them, the parameters of the solid electrolyte are shown in Table 1.

[0093] The preparation method of the solid electrolyte of Example 6 includes the following steps: (1) Preparation of di(10-undecen-1-yl) ester grafted fullerene: Dissolve 5.7 parts by mass of 2yne, 23 parts by mass of CBr4, and 1 part of fullerene C60 in an o-dichlorobenzene solution, fully dissolve after stirring for 30 minutes, add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, then spin dry with a rotary evaporator to obtain di(10-undecen-1-yl) ester grafted fullerene.

[0094] (2) Preparation of solid electrolyte: Dissolve 22 parts by mass of di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of vinyl modified PEO (weight average molecular weight 750), 43.3 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI, and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0095] Among them, the parameters of the solid electrolyte are shown in Table 1.

[0096] The preparation method of the solid electrolyte in Example 7 includes the following steps: (1) Preparation of fullerene grafted onto di(10-undecen-1-yl) malonate: 5.7 parts by weight of 2yne, 23 parts by weight of CBr4, and 1 part by weight of fullerene C60 were dissolved in o-dichlorobenzene solution. After stirring for 30 minutes until fully dissolved, 3.2 parts by weight of catalyst DBU were added at 0 degrees Celsius. After reacting for 4 hours, the insoluble matter was filtered off, and then purified by silica gel column chromatography. The silica gel column was eluted with toluene and dichloromethane (volume ratio 1:1). The eluent was collected, concentrated, and then precipitated three times with methanol. After drying by rotary evaporation, di(10-undecen-1-yl)malonate grafted fullerene was obtained.

[0097] (2) Preparation of solid electrolytes: 22 parts by mass of di(10-undecen-1-yl)malonate grafted with fullerene, 41 parts by mass of vinyl-modified PEO (weight average molecular weight 750), 30.5 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 were dissolved in THF, stirred evenly, coated onto copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0098] Examples 8-12 The difference between Examples 8-12 and Example 1 is that the weight-average molecular weight of PEO is changed, as shown in Table 2.

[0099] Examples 13-16 The difference between Examples 13-16 and Example 1 is that the amount of raw materials added in step (2) is changed, thereby changing the proportion of di(10-undecen-1-yl)malonic acid grafted fullerene and vinyl-modified PEO, as shown in Table 2.

[0100] The preparation method of the solid electrolyte in Example 13 includes the following steps: (1) Preparation of fullerene grafted onto di(10-undecen-1-yl) malonate: 5.7 parts by weight of 2yne, 23 parts by weight of CBr4, and 1 part by weight of fullerene C60 were dissolved in o-dichlorobenzene solution. After stirring for 30 minutes until fully dissolved, 3.2 parts by weight of catalyst DBU were added at 0 degrees Celsius. After reacting for 4 hours, the insoluble matter was filtered off, and then purified by silica gel column chromatography. The silica gel column was eluted with toluene and dichloromethane (volume ratio 1:1). The eluent was collected, concentrated, and then precipitated three times with methanol. After drying by rotary evaporation, di(10-undecen-1-yl)malonate grafted fullerene was obtained.

[0101] (2) Preparation of the solid-state electrolyte: 22 parts by mass of di(10-undecen-1-yl) malonate grafted fullerene, 58 parts by mass of vinyl-modified PEO (weight average molecular weight: 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight: 750), 27.7 parts of LiTFSI, and 0.354 parts of a photoinitiator 2959 were dissolved in THF, stirred uniformly, coated onto a copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0102] The preparation method of the solid-state electrolyte of Example 14 includes the following steps: (1) Preparation of di(10-undecen-1-yl) malonate grafted fullerene: 5.7 parts by mass of 2yne, 23 parts by mass of CBr4, and 1 part of fullerene C60 were dissolved in an o-dichlorobenzene solution, stirred for 30 minutes to fully dissolve, and then 3.2 parts of a catalyst DBU was added at 0 degrees. After reacting for 4 hours, the insoluble matter was first filtered, and then purified on a silica gel column. Toluene and dichloromethane (volume ratio of 1:1) were used as eluents to elute the silica gel column. The eluate was collected, concentrated, and then precipitated three times with methanol. After drying with a rotary evaporator, di(10-undecen-1-yl) malonate grafted fullerene was obtained.

[0103] (2) Preparation of the solid-state electrolyte: 22 parts by mass of di(10-undecen-1-yl) malonate grafted fullerene, 58 parts by mass of vinyl-modified PEO (weight average molecular weight: 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight: 750), 27.7 parts of LiTFSI, and 0.354 parts of a photoinitiator 2959 were dissolved in THF, stirred uniformly, coated onto a copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0104] The preparation method of the solid-state electrolyte of Example 15 includes the following steps: (1) Preparation of di(10-undecen-1-yl) malonate grafted fullerene: 5.7 parts by mass of 2yne, 23 parts by mass of CBr4, and 1 part of fullerene C60 were dissolved in an o-dichlorobenzene solution, stirred for 30 minutes to fully dissolve, and then 3.2 parts of a catalyst DBU was added at 0 degrees. After reacting for 4 hours, the insoluble matter was first filtered, and then purified on a silica gel column. Toluene and dichloromethane (volume ratio of 1:1) were used as eluents to elute the silica gel column. The eluate was collected, concentrated, and then precipitated three times with methanol. After drying with a rotary evaporator, di(10-undecen-1-yl) malonate grafted fullerene was obtained.

[0105] (2) Preparation of the solid-state electrolyte: Dialkyl 10-undecen-1-yl malonate grafted fullerene 22 parts by mass, vinyl modified PEO (weight average molecular weight 750) 45 parts by mass, polyethylene oxide (PEO, weight average molecular weight 750) 37 parts, LiTFSI 27.7 parts, and photoinitiator 2959 0.354 parts were dissolved in THF, stirred uniformly, coated onto a copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0106] The preparation method of the solid-state electrolyte of Example 16 includes the following steps: (1) Preparation of dialkyl 10-undecen-1-yl malonate grafted fullerene: Dissolve 5.7 parts by mass of 2yne, 23 parts by mass of CBr4, and 1 part of fullerene C60 in an o-dichlorobenzene solution, stir for 30 minutes to dissolve completely, then add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter out the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, and then dry with a rotary evaporator to obtain dialkyl 10-undecen-1-yl malonate grafted fullerene.

[0107] (2) Preparation of a solid-state electrolyte: Dialkyl 10-undecen-1-yl malonate grafted fullerene 22 parts by mass, vinyl modified PEO (weight average molecular weight 750) 45 parts by mass, polyethylene oxide (PEO, weight average molecular weight 750) 37 parts, LiTFSI 27.7 parts, and photoinitiator 2959 0.354 parts were dissolved in THF, stirred uniformly, coated onto a copper foil, dried at 55 degrees for 1 hour, and then irradiated with ultraviolet light for 1 hour to obtain a solid-state electrolyte.

[0108] Examples 17-19 Examples 17-19 differ from Example 1 in that the weight average molecular weight of the vinyl modified PEO is changed by changing the reaction temperature and time in step (2), as shown in Table 2.

[0109] Examples 20-22 Examples 20-22 differ from Example 1 in that the grafting rate of dialkyl 10-undecen-1-yl malonate grafted fullerene is changed by changing the amount of raw materials added in step (1), as shown in Table 2.

[0110] The preparation method of the solid-state electrolyte of Example 20 includes the following steps: (1) Preparation of dialkyl 10-undecen-1-yl malonate grafted fullerene: Dissolve 5.2 parts by mass of 2yne, 23 parts by mass of CBr4 and 1 part of fullerene C60 in o-dichlorobenzene solution, after stirring for 30 minutes to fully dissolve, add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, then spin dry with a rotary evaporator to obtain di(10-undecen-1-yl) ester grafted fullerene.

[0111] (2) Preparation of solid electrolyte: Dissolve 22 parts by mass of di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of vinyl modified PEO (weight average molecular weight 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0112] The preparation method of the solid electrolyte of Example 21 comprises the following steps: (1) Preparation of di(10-undecen-1-yl) ester grafted fullerene: Dissolve 4.6 parts by mass of 2yne, 23 parts by mass of CBr4 and 1 part of fullerene C60 in o-dichlorobenzene solution, after stirring for 30 minutes to fully dissolve, add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, then spin dry with a rotary evaporator to obtain di(10-undecen-1-yl) ester grafted fullerene.

[0113] (2) Preparation of solid electrolyte: Dissolve 22 parts by mass of di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of vinyl modified PEO (weight average molecular weight 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0114] The preparation method of the solid electrolyte of Example 22 comprises the following steps: (1) Preparation of di(10-undecen-1-yl) ester grafted fullerene: Dissolve 5.5 parts by mass of 2yne, 23 parts by mass of CBr4 and 1 part of fullerene C60 in o-dichlorobenzene solution, after stirring for 30 minutes to dissolve completely, add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, then spin dry with a rotary evaporator to obtain di(10-undecen-1-yl) ester grafted fullerene.

[0115] (2) Preparation of solid electrolyte: Dissolve 22 parts by mass of di(10-undecen-1-yl) ester grafted fullerene, 41 parts by mass of vinyl modified PEO (weight average molecular weight 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0116] Comparative Example 1 Comparative Example 1 differs from Example 1 in that Comparative Example 1 directly adds an equal amount of vinyl modified PEO (the amount of di(10-undecen-1-yl) ester grafted fullerene is replaced with an equal amount of vinyl modified PEO).

[0117] A method for preparing a solid electrolyte, comprising the following steps: (1) Preparation of solid electrolyte: Dissolve 63 parts by mass of vinyl modified vinyl modified PEO (weight average molecular weight 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0118] Among them, the parameters of the solid electrolyte are shown in Table 1.

[0119] Comparative Example 2 Comparative Example 2 differs from Example 1 in that Comparative Example 2 directly adds an equal amount of di(10-undecen-1-yl) ester grafted fullerene (the amount of vinyl modified PEO is replaced with an equal amount of di(10-undecen-1-yl) ester grafted fullerene).

[0120] A method for preparing a solid electrolyte, comprising the following steps: (1) Preparation of di(10-undecen-1-yl) ester grafted fullerene: Dissolve 5.7 parts by mass of 2yne, 23 parts by mass of CBr4 and 1 part of fullerene C60 in o-dichlorobenzene solution, after stirring for 30 minutes to dissolve completely, add 3.2 parts of catalyst DBU at 0 degrees. After reacting for 4 hours, first filter the insoluble matter, then purify on a silica gel column, use toluene and dichloromethane (volume ratio 1:1) as eluent to elute the silica gel column, collect the eluate, concentrate the eluate, then precipitate three times with methanol, then spin dry with a rotary evaporator to obtain di(10-undecen-1-yl) malonate grafted fullerene.

[0121] As shown in Figure 1 , by testing the 13C NMR of di(10-undecen-1-yl) malonate grafted fullerene, di(10-undecen-1-yl) malonate peaks appear as shown in Figure 1 , indicating that the chemical grafting is successful.

[0122] (2) Preparation of solid electrolyte: Dissolve 63 parts by mass of di(10-undecen-1-yl) malonate grafted fullerene, 37 parts of vinyl modified PEO (weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0123] Comparative Example 3 Comparative Example 3 differs from Example 1 in that Comparative Example 3 uses an equal amount of fullerene to replace di(10-undecen-1-yl) malonate grafted fullerene.

[0124] A method for preparing a solid electrolyte, comprising the following steps: Preparation of solid electrolyte: Dissolve 22 parts by mass of fullerene, 41 parts of vinyl modified polyethylene oxide (vinyl modified PEO (weight average molecular weight 750), 37 parts of polyethylene oxide (PEO, weight average molecular weight 750), 27.7 parts of LiTFSI and 0.354 parts of photoinitiator 2959 in THF, stir uniformly, coat on a copper foil, dry at 55 degrees for 1 hour, then irradiate with ultraviolet light for 1 hour to obtain a solid electrolyte.

[0125] Table 1 Composition table of solid electrolyte Table 2 Parameter table of solid electrolyte Performance test 1. Use a universal tensile testing machine to measure the Young's modulus of the solid electrolyte prepared in the examples and comparative examples.

[0126] 2. Measure the ionic conductivity and lithium ion transference number with electrochemical analysis workstation.

[0127] 3. Cycle number: Test the cycle performance by the button cell: Mixing the lithium iron phosphate, carbon black and PVDF (mass ratio 7:2:1) uniformly, then adding the solvent NMP, finally obtaining the slurry with solid content of 60% by stirring. Then evenly coating the slurry on the 12 μm aluminum current collector, and baking in the vacuum oven at 80 degrees for 24 hours to obtain the required positive electrode sheet; Mixing the graphite, carbon black and CMC (mass ratio 7:2:1) uniformly, then adding deionized water, finally obtaining the slurry with solid content of 50% by stirring. Then evenly coating the slurry on the 6 μm copper current collector, and baking in the vacuum oven at 80 degrees for 24 hours to obtain the required negative electrode sheet; Cutting the positive electrode sheet and the negative electrode sheet into a round sheet with a diameter of 1.2 centimeters, and assembling the button cell by placing the solid-state electrolyte of the example and the comparative example between the positive electrode sheet and the negative electrode sheet. Cycle at a rate of 0.33C, and record the cycle number until the cutoff of 90% SOH.

[0128] Table 3 test results Note: Comparative Example 1 is in a viscous state and cannot be tested for Young's modulus.

[0129] As can be seen from Table 3, the solid-state electrolyte described in the present application comprises a polymer solid-state electrolyte, a lithium salt and a cross-linked copolymer, the cross-linked copolymer comprises a polymer solid-state electrolyte containing a carbon-carbon double bond and a propandioic acid di(10-undecen-1-yl) ester grafted fullerene, the cross-linked copolymer can provide a certain active material expansion space, improve the stability of the solid-state electrolyte, avoid the crystallization of the polymer solid-state electrolyte, effectively improve the transmission efficiency of lithium ions, the propandioic acid di(10-undecen-1-yl) ester grafted fullerene can absorb free radicals generated in the cycle process of the secondary battery, while effectively improving the lithium ion transference number, and improving the mechanical properties of the solid-state electrolyte, effectively improving the cycle life of the secondary battery.

[0130] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A solid state electrolyte, characterized by, The solid-state electrolyte includes a polymer solid-state electrolyte, a lithium salt, and a crosslinked copolymer; the crosslinked copolymer includes a polymer solid-state electrolyte containing a carbon-carbon double bond and a di(10-undecen-1-yl) propanedioate grafted fullerene.

2. The solid-state electrolyte of claim 1, wherein, At least one of the following (I) to (III) is satisfied: (I) the mass percentage content of the polymer solid-state electrolyte in the solid-state electrolyte is 18 to 26%; (II) the mass percentage content of the lithium salt in the solid-state electrolyte is 31 to 38%; (III) the mass percentage content of the crosslinked copolymer in the solid-state electrolyte is 45 to 52%.

3. The solid-state electrolyte of claim 1, wherein, The mass percentage content of the polymer solid-state electrolyte containing a carbon-carbon double bond in the crosslinked copolymer is 60 to 72%; and / or The mass percentage content of the di(10-undecen-1-yl) propanedioate grafted fullerene in the crosslinked copolymer is 28 to 40%.

4. The solid-state electrolyte of claim 1, wherein, The grafting rate of di(10-undecen-1-yl) propanedioate in the di(10-undecen-1-yl) propanedioate grafted fullerene is 62 to 77%.

5. The solid-state electrolyte of claim 1, wherein, The weight average molecular weight of the polymer solid-state electrolyte containing a carbon-carbon double bond is 400 to 1050. The weight average molecular weight of the polymer solid-state electrolyte is 400 to 1050.

6. The solid-state electrolyte of claim 1, wherein, At least one of the following: the polymer solid-state electrolyte includes at least one of a polymer containing a carbon-carbon double bond, a polymer containing a carbon-carbon double bond, and a polymer containing a carbon-carbon double bond.

7. The solid-state electrolyte of claim 1, wherein, The polymer solid-state electrolyte includes at least one of polyethylene oxide, polyvinylpyrrolidone, polyvinylidene fluoride, polyacrylonitrile, polyethylene glycol, and polyethylene glycol dimethyl ether.

8. The solid-state electrolyte of claim 1, wherein, The lithium salt includes at least one of LiTFSI, LiPF6, LiFSI, LiClO4, LiBTFSI, LiTPBTFSI, LiDFP, LiDFTFSI, and LiFTFSI.

9. A secondary battery characterized by comprising: The solid-state electrolyte includes at least one of the solid-state electrolytes according to any one of claims 1 to 8.

10. An electrical device, characterized by The secondary battery according to claim 9 is used as a power supply for the electric device.

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