Preparation method for fluoro-1,3-dioxolane compound, in-situ solid electrolyte, and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of solid-state batteries, and provides a preparation method for a fluoro-1,3-dioxolane compound, an in-situ solid electrolyte, and a preparation method therefor and a use thereof. The in-situ solid electrolyte is obtained by curing a mixture comprising the fluoro-1,3-dioxolane compound, a free radical polymerization monomer, a first initiator, a second initiator, an electrolyte salt, and a non-aqueous organic solvent. By means of the exothermic ionic polymerization of fluoro-1,3-dioxolane compound at room temperature, free radical monomer polymerization is initiated, avoiding non-uniform polymerization caused by external heating. In addition, the free radical monomer polymerization can consume heat released by ion polymerization, resulting in a milder curing process without bubble residues, so that the in-situ solid electrolyte is more uniform in polymerization, and has better contact with an electrode. Upon research, the in-situ solid electrolyte has a wide electrochemical window, an oxidation voltage greater than 4.5 V, and ionic conductivity greater than 5×10-4 S / cm.

Description

Preparation method of fluorinated 1,3-dioxolane heterocyclic compound, in-situ solid-state electrolyte, and preparation method and application thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 2023116962388 filed with the Patent Office of China on December 12, 2023, entitled “A method for preparing a fluorinated-1,3-dioxolane heterocyclic compound, an in-situ solid-state electrolyte, and its preparation method and application,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure belongs to the field of solid-state battery technology, and specifically relates to a preparation method of a fluorinated-1,3-dioxolane heterocyclic compound, an in-situ solid-state electrolyte, and a preparation method and application thereof. Background Art

[0004] Solid-state electrolytes are a key development direction in electric vehicle battery technology and are closely linked to EV safety. In recent years, a variety of solid-state electrolytes have been developed, including inorganic solid-state electrolytes (e.g., sulfides, oxides, halides, and antiperovskites) and polymer electrolytes. Inorganic solid-state electrolytes offer high ionic conductivity but suffer from poor chemical stability or mechanical properties. Polymer electrolytes offer good mechanical properties but poor ionic conductivity. Furthermore, given the complex preparation processes of traditional solid-state electrolytes, an in-situ solidification technique has been proposed to prepare them. This technique involves mixing electrolyte materials and an electrolyte solution, followed by polymerization at low temperature, to form a stable in-situ solid-state electrolyte. These in-situ solid-state electrolytes exhibit excellent thermal stability, electrochemical performance, and safety, effectively improving battery safety and reliability while offering high energy density and low cost.

[0005] Currently, common polymerization monomers for in-situ solid-state electrolytes include acrylates, epoxides, and olefinic substances. Among them, the epoxide 1,3-dioxolane (DOL) has been widely studied due to its advantages after polymerization, such as good ionic conductivity, low interfacial resistance, high mechanical strength, and good lithium metal compatibility. However, during the in-situ polymerization process of DOL in batteries, the degree of polymerization is often low, forming a gel-like electrolyte. This results in a low oxidation voltage window, limiting its application in high-voltage batteries.

[0006] In order to improve the oxidation window of in-situ solid-state electrolytes, researchers have proposed introducing strongly electronegative groups, such as halogen groups, alkyl halide groups, or alkyl thiolate groups, into the polymer monomer structure. Patent CN107353276A discloses a method for preparing halogenated 2,2-di(perfluorosubstituted)1,3-dioxolane. In the presence of a catalyst, 2,2-di(perfluorosubstituted)1,3-dioxolane reacts with Cl2 and HF to obtain halogenated 2,2-di(perfluorosubstituted)1,3-dioxolane. However, the substances synthesized in this patent are mainly halogenated 2,2-di(perfluorosubstituted)1,3-dioxolane, and the purity is relatively low.

[0007] In addition, in the process of preparing large-scale solid electrolytes by in-situ polymerization, due to the different thermal conductivity coefficients of different phases (solid phase, liquid phase, etc.), the solid electrolyte precursor liquid component near the edge of the pole piece is first cured by heat and the internal component is cured later, resulting in different molecular weights, curing degrees, etc. of polymerization in different parts. The solid electrolyte formed is difficult to obtain good uniformity, which will have an adverse effect on the performance of the battery. Based on this, patent CN114122512A discloses a method for copolymerization of room temperature polymerization type monomers and high temperature polymerization type monomers, in which the high temperature polymerization type monomers are confined by the network formed by the room temperature curing type monomers, and the influence of factors such as the uneven heating equipment itself and the uneven temperature conduction is weakened on the polymerization under high temperature. This method can improve polymerization uniformity to a certain extent, but the subsequent high temperature curing process still has the problem of uneven heating, and the polymerization process is an exothermic reaction, which can cause the gasification of organic small molecules, and the polymer product often has a higher viscosity. The gasified small molecules are difficult to discharge therefrom, and the small molecule gas not eliminated will be retained in the electrolyte to form tiny bubbles. These bubbles do not have the ability of ion transmission, hinder ion transmission in the electrolyte, and even cause some active substances to lose contact with the electrolyte, causing the battery capacity to decay. In addition, the vaporized electrolyte small molecules have a low voltage window and a low ignition point, and may decompose and support combustion during actual application, posing a potential danger.

[0008] Application Contents

[0009] The present invention aims to provide a method for preparing a fluoro-1,3-dioxolane heterocyclic compound, an in-situ solid electrolyte, and its preparation method and application. The in-situ solid electrolyte has high ionic conductivity and a wide electrochemical window, and is suitable for high voltage systems.

[0010] In order to achieve the above-mentioned purpose of the present disclosure, the following technical solutions are adopted:

[0011] In a first aspect, the present disclosure provides an in-situ solid-state electrolyte obtained by solidifying a mixture;

[0012] The mixture includes a fluoro-1,3-dioxolane heterocyclic compound, a free radical polymerization monomer, a first initiator, a second initiator, an electrolyte salt and a non-aqueous organic solvent;

[0013] The fluoro-1,3-dioxolane heterocyclic compound is selected from any one of the following formulas I to X:

[0014] Furthermore, the free radical polymerization monomer is selected from any one or more of vinyl ethylene carbonate, methyl vinyl sulfone, ethyl vinyl sulfone, triethylene glycol divinyl ether, methyl methacrylate, vinyl acetate, 1,3-propenyl-sultone, acrylamide, ethyl methacrylate, n-butyl methacrylate, vinylene carbonate, maleic anhydride, succinonitrile, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, vinyl acetate, polyethylene glycol diacrylate or n-butyl acrylate.

[0015] Furthermore, the first initiator is selected from azo initiators and / or peroxide initiators.

[0016] Furthermore, the second initiator is selected from any one or more of lithium hexafluorophosphate, sodium hexafluorophosphate, lithium tetrafluoroborate, sodium tetrafluoroborate, lithium difluorooxalatoborate, sodium difluorooxalatoborate, boron trifluoride, niobium pentachloride, titanium tetrachloride, aluminum chloride, ferric chloride or aluminum trifluoromethanesulfonate.

[0017] Furthermore, the electrolyte salt includes lithium salt and sodium salt.

[0018] Furthermore, the lithium salt is selected from any one or more of LiPF6, LiClO4, LiBF4, LiPOF2, LiTFSI, LiFSI, LiODFB or LiBOB.

[0019] Furthermore, the sodium salt is selected from any one or more of NaPF6, NaClO4, NaBF4, NaTFSI, NaFSI or NaODFB.

[0020] Furthermore, the non-aqueous organic solvent is selected from any one or more of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate or ethylene glycol dimethyl ether.

[0021] Furthermore, the oxidation voltage of the in-situ solid electrolyte is greater than 4.5 V, which is applicable to high voltage systems, and the ionic conductivity is greater than 5×10 -4 S / cm.

[0022] In a second aspect, the present disclosure provides a method for preparing the in-situ solid-state electrolyte involved in the above technical solution, comprising the following steps:

[0023] S1: mixing a first initiator with a fluoro-1,3-dioxolane heterocyclic compound represented by any one of Formulas I to X to obtain a first polymerization precursor solution; mixing an electrolyte salt, a second initiator, a free radical polymerization monomer, and a non-aqueous organic solvent to obtain a second polymerization precursor solution;

[0024] S2: After mixing the polymerization precursor solution 1 and the polymerization precursor solution 2, a polymerization precursor electrolyte is obtained, which is injected into a battery containing a positive electrode active material for solidification to obtain an in-situ solidified electrolyte.

[0025] Furthermore, in step S1, the mass ratio of the non-aqueous organic solvent to the free radical polymerization monomer is 5:(1-10).

[0026] Furthermore, the mass fraction of the first initiator in the first polymerization precursor solution is 0.01% to 5%.

[0027] Furthermore, the mass fraction of the second initiator in the second polymerization precursor solution is 0.01% to 3%.

[0028] Furthermore, the mass fraction of the electrolyte salt in the second polymerization precursor solution is 12% to 30%.

[0029] Furthermore, in step S2, the mass ratio of the first polymerization precursor solution to the second polymerization precursor solution is 1:(1-5).

[0030] Furthermore, the polymerization is room temperature polymerization, and the polymerization time is 12 to 72 hours.

[0031] In a third aspect, the present disclosure provides a solid-state secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte;

[0032] The electrolyte is the in-situ solid-state electrolyte involved in the above technical solution.

[0033] Furthermore, the solid-state secondary battery is a solid-state lithium-ion battery or a solid-state sodium-ion battery.

[0034] In a fourth aspect, the present disclosure provides a method for preparing a fluoro-1,3-dioxolane heterocyclic compound, comprising the following steps:

[0035] In a protective atmosphere, a vinyl compound solution and CO2F2 are mixed, and an addition reaction occurs under the catalysis of the foam metal. The solvent is removed and the fluorinated-1,3-dioxolane heterocyclic compound is obtained after purification.

[0036] Furthermore, the protective atmosphere is argon.

[0037] Furthermore, the foam metal is selected from any one or more of foam iron, foam nickel or foam copper.

[0038] Furthermore, the molar ratio of the vinyl compound to CO2F2 in the vinyl compound solution is 1:(1-5).

[0039] Furthermore, the temperature of the addition reaction is -50 to -25°C, and the time of the addition reaction is 6 to 48 hours.

[0040] Furthermore, the vinyl compound solution is obtained by mixing the vinyl compound and a solvent at -50 to -25°C in a protective atmosphere and then heating the mixture to room temperature.

[0041] Furthermore, the solvent in the vinyl compound solution is selected from any one or more of acetonitrile, dichloromethane, chloroform, dichloroethane, propanol, acetone, dioxane, tetrahydrofuran, methyl ethyl ketone, n-butanol, ethyl acetate, ether or chloroform.

[0042] Furthermore, the vinyl compound in the vinyl compound solution is selected from any one of the following formulas A to J:

[0043] Furthermore, the molar ratio of the vinyl compound to the solvent is 1:(2-10).

[0044] Furthermore, the heating rate is 0.1-5°C / min.

[0045] Furthermore, after the addition reaction is completed, the mixture is heated to room temperature under a protective atmosphere, and then the solvent is removed to obtain the fluoro-1,3-dioxolane heterocyclic compound.

[0046] In the present disclosure, the room temperature refers to a temperature of "20 to 30°C", further 25°C. DETAILED DESCRIPTION

[0047] To address the problems of low oxidation voltage and low ionic conductivity of in-situ solid-state electrolytes in the prior art, the present disclosure first provides a polymerizable monomer in an in-situ solid-state electrolyte, namely a fluoro-1,3-dioxolane heterocyclic compound (FDOL), the preparation method of which comprises the following steps:

[0048] In a protective atmosphere, a vinyl compound solution and CO2F2 undergo addition reaction at -50 to -25°C in the presence of foamed metal, and the solvent is removed and FDOL is obtained after purification.

[0049] In the present disclosure, the vinyl compound solution is prepared by mixing the vinyl compound with a solvent at a low temperature of -50 to -25°C, further at -45 to -30°C under a protective atmosphere, and then heating to room temperature. The low temperature is controlled by liquid nitrogen. The solvent is an inert solvent, specifically any one or more selected from acetonitrile, dichloromethane, chloroform, dichloroethane, propanol, acetone, dioxane, tetrahydrofuran, methyl ethyl ketone, n-butanol, ethyl acetate, ether, or chloroform.

[0050] The present disclosure has no particular limitation on the source of the above-mentioned solvent, and it can be a common commercial product.

[0051] The protective atmosphere is one of high-purity argon or nitrogen, and further is high-purity argon.

[0052] The vinyl compound is selected from any one of the following formulas A to J:

[0053] In some embodiments of the present disclosure, the molar ratio of the vinyl compound to the solvent is 1:(2-10), specifically 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10, etc. Since the reaction yield is sensitive to the heating rate, the heating rate of the heating in the present disclosure is 0.1-5°C / min, and can be 0.1°C / min, 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, 4°C / min, or 5°C / min, etc.

[0054] After obtaining the vinyl compound solution, according to the present disclosure, in a protective atmosphere, the vinyl compound solution and CO2F2 are subjected to an addition reaction at -50 to -25°C, further at -45 to -30°C and in the presence of a foamed metal, the reaction equation of which is shown below:

[0055] Wherein, R1, R2, R3, and R4 are independently selected from one or more of H, F, sulfonic acid, carboxylic acid ester, trimethylmethoxysilyl, or cyano groups, but are not both H and F. The F element can further enhance the oxidative stability of the electrolyte; the sulfonic acid group can improve the battery's performance in terms of suppressing gas production and high temperature; the carboxylic acid ester group itself has good stability and strong complexing ability for lithium / sodium ions, which can effectively enhance the battery's low-temperature performance; the trimethylmethoxysilane and cyano functional groups can remove excess HF generated in the electrolyte, inhibiting battery performance degradation caused by high HF content and excessive gas production.

[0056] The protective atmosphere is as described above and will not be repeated here.

[0057] The foam metal is used as a catalyst to catalyze the addition reaction between the vinyl compound and CO2F2. The foam metal is mainly a foam transition metal, which can be selected from any one or more of foam iron, foam nickel or foam copper.

[0058] In the present disclosure, the molar ratio of the vinyl compound to CO2F2 in the vinyl compound solution is 1:(1-5), and further 1:1.

[0059] In some embodiments of the present disclosure, liquid nitrogen is used to control the temperature at -50 to -25°C. A vinyl compound solution is added to a stainless steel passivation reactor, CO₂F₂ is condensed into the reactor, and a metal foam is placed to catalyze the reaction. At a low temperature of -50 to -25°C, the vinyl compound and CO₂F₂ undergo an addition reaction on the metal foam surface for 6 to 48 hours, preferably 12 to 30 hours.

[0060] In some embodiments of the present disclosure, after the addition reaction is completed, the solvent is removed to obtain pure FDOL.

[0061] The present invention controls the heating rate under a protective atmosphere so that the reactor reaches room temperature within 12 to 48 hours, and further within 20 to 30 hours, so as to facilitate subsequent removal of the solvent by rotary evaporation, thereby obtaining pure FDOL.

[0062] In the present disclosure, the rotary evaporation can be carried out according to technical means well known to those skilled in the art, and the temperature is 35-60°C, and further 40°C.

[0063] In the present disclosure, the yield of the aforementioned FDOL product is >90%. It can be separated and purified using a chromatography column to obtain FDOL with a purity >99%, which can be used as a subsequent comonomer. The obtained FDOL can be directly used as a monomer for electrolyte polymerization. FODL can also be cross-linked with other polymers to form an ion transport network, which helps improve ionic conductivity.

[0064] The preparation method of the FDOL provided by the present disclosure uses a foamed transition metal catalyst to synthesize FDOL in a conventional solvent, allowing the reaction to be carried out at a higher temperature, thereby reducing the preparation cost. The preparation method has a high yield of greater than 90%.

[0065] The present disclosure also provides an in-situ solid-state electrolyte, which is obtained by solidifying the mixture;

[0066] The mixture includes a fluoro-1,3-dioxolane heterocyclic compound, a free radical polymerization monomer, a first initiator, a second initiator, an electrolyte salt and a non-aqueous organic solvent;

[0067] The fluoro-1,3-dioxolane heterocyclic compound is selected from any one of the following formulas I to X:

[0068] In the present disclosure, the free radical polymerization monomer is selected from any one or more of vinyl ethylene carbonate, methyl vinyl sulfone, ethyl vinyl sulfone, triethylene glycol divinyl ether, methyl methacrylate, vinyl acetate, 1,3-propenyl-sultone, acrylamide, ethyl methacrylate, n-butyl methacrylate, vinyl carbonate, maleic anhydride, succinonitrile, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, vinyl acetate, polyethylene glycol diacrylate or n-butyl acrylate; the first initiator is selected from azo initiators and / or peroxide initiators; the second initiator is selected from lithium hexafluorophosphate, sodium hexafluorophosphate, lithium tetrafluoroborate, sodium tetrafluoroborate, lithium difluorooxalatoborate, difluoroborate, and the like. Any one or more of sodium fluorooxalatoborate, boron trifluoride, niobium pentachloride, titanium tetrachloride, aluminum chloride, ferric chloride or aluminum trifluoromethanesulfonate; the electrolyte salt includes a lithium salt or a sodium salt; the lithium salt is selected from any one or more of LiPF6, LiClO4, LiBF4, LiPOF2, LiTFSI, LiFSI, LiODFB or LiBOB; the sodium salt is selected from any one or more of NaPF6, NaClO4, NaBF4, NaTFSI, NaFSI or NaODFB; the non-aqueous organic solvent is selected from any one or more of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate or ethylene glycol dimethyl ether.

[0069] The present disclosure also provides a method for preparing the above-mentioned in-situ solid-state electrolyte, comprising the following steps:

[0070] S1: mixing a first initiator with a fluoro-1,3-dioxolane heterocyclic compound represented by any one of Formulas I to X to obtain a first polymerization precursor solution; mixing an electrolyte salt, a second initiator, a free radical polymerization monomer, and a non-aqueous organic solvent to obtain a second polymerization precursor solution;

[0071] S2: After mixing the polymerization precursor solution 1 and the polymerization precursor solution 2, a polymerization precursor electrolyte is obtained, which is injected into the battery and solidified to obtain an in-situ solid electrolyte.

[0072] According to the present disclosure, a first initiator is mixed with a fluoro-1,3-dioxolane heterocyclic compound represented by any one of Formulas I to X to obtain a first polymerization precursor solution. The selection of the first initiator is as described in the relevant content of the above technical solution and will not be repeated here. Simultaneously, an electrolyte salt, a second initiator, a free radical polymerization monomer, and a non-aqueous organic solvent are mixed to obtain a second polymerization precursor solution. The specific selection of the electrolyte salt, the second initiator, the free radical polymerization monomer, and the non-aqueous organic solvent is as described in the relevant content of the above technical solution and will not be repeated here.

[0073] In some embodiments of the present disclosure, the mass ratio of the non-aqueous organic solvent to the free radical polymerization monomer is 5:(1-10), further 5:(2-6).

[0074] In the present disclosure, the first initiator is used to initiate polymerization of free radical polymerization monomers, and the mass fraction of the first initiator in the first polymerization precursor solution is 0.01% to 5%, and further 0.1% to 3%. The second initiator is used to initiate polymerization of a fluoro-1,3-dioxolane heterocyclic compound, and the mass fraction of the second initiator in the second polymerization precursor solution is 0.01% to 3%, and further 0.05% to 1%.

[0075] In the present disclosure, the mass fraction of the electrolyte salt in the second polymerization precursor solution is 12% to 30%, further 15% to 25%.

[0076] According to the above technical solution, after preparing the polymerization precursor solution 1 and the polymerization precursor solution 2, the two are mixed to obtain a polymerization precursor electrolyte, which is injected into the battery and solidified to obtain an in-situ solid-state electrolyte.

[0077] In some embodiments of the present disclosure, the mass ratio of the first polymerization precursor solution to the second polymerization precursor solution is 1:(1-5), and further is 1:(2-3).

[0078] In the present disclosure, the mixing is performed under stirring conditions at a stirring rate of 400 to 800 r / min, preferably 500 r / min, and for a stirring time of 0.5 to 3 hours, preferably 1 to 2 hours. In the present disclosure, after the polymer precursor electrolyte is injected into the battery, it is allowed to stand at room temperature for 12 to 72 hours, preferably 20 to 40 hours, to complete solidification and obtain an in-situ solidified electrolyte.

[0079] In the preparation method disclosed herein, the exothermic ionic polymerization of the fluoro-1,3-dioxolane heterocyclic compound at room temperature triggers the polymerization of free radical polymerization monomers, thereby avoiding uneven polymerization caused by external heating. Furthermore, the free radical polymerization of the monomers dissipates the heat released by ionic polymerization, resulting in a gentler curing process with no residual bubbles. This results in more uniform polymerization of the resulting in-situ solid electrolyte and better contact with the electrodes.

[0080] In order to test the performance of the in-situ solid-state electrolyte prepared by the above preparation method, the present disclosure assembled a button battery, and the specific steps are as follows:

[0081] The positive electrode material, conductive carbon, and polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 96:2:2 and ball-milled for 12-24 hours. The solvent was N-methylpyrrolidone (NMP), and the solid-liquid ratio was 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 6-12 hours. The active material surface density was controlled to 5-15 mg cm -2 . 12mm positive electrode discs were obtained by cutting.

[0082] Ionic conductivity testing was performed on a battery assembled with steel sheet || separator || steel sheet and blocking electrodes on both sides. Voltage window testing was performed on a battery assembled with steel sheet || separator || lithium / sodium metal, using lithium metal as the reference and counter electrodes and the steel sheet as the working electrode. Charge and discharge testing was performed on a half-cell assembled with a positive electrode || separator || lithium / sodium metal anode.

[0083] The polymer precursor electrolyte was injected into the assembled battery and then solidified before testing. It should be noted that in the button cell, the injection volume of the polymer precursor electrolyte was 80 μL based on the active material of the positive electrode of the button cell.

[0084] According to the test, the oxidation voltage of the in-situ solid electrolyte is greater than 4.5V, and the ionic conductivity is greater than 5×10 -4 Taking lithium-ion half-cell as an example, the cycle capacity retention rate (100 cycles) is above 90%.

[0085] Given the high oxidation voltage and ionic conductivity of the in-situ solidified electrolyte, and the excellent cycling performance of the resulting battery, the present disclosure further provides a solid-state secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the electrolyte is the in-situ solidified electrolyte described in the above technical solution. In the present disclosure, the solid-state secondary battery is a solid-state lithium-ion battery or a solid-state sodium-ion battery.

[0086] For solid-state lithium-ion batteries, the positive electrode is made by mixing active materials, conductive agents and binders in proportion, adding solvent to obtain a slurry and coating it on aluminum foil, drying, rolling and cutting. The active materials are lithium cobalt oxide (LiCoO2), lithium iron phosphate (Li3Fe2(PO4)3) and ternary nickel cobalt manganese positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622) or LiNi 0.8 Co 0.1 Mn 0.1O2 (NCM811), the conductive agent is conductive carbon black (SuperP), and the binder is preferably polyvinylidene fluoride (PVDF). The mass ratio of the active material, conductive agent, and binder is 96:2:2. The solvent is N-methylpyrrolidone (NMP). The negative electrode is a metal lithium sheet, and the separator is a polyethylene separator and / or a polypropylene separator.

[0087] For solid-state sodium ion batteries, the positive electrode is made by mixing active materials, conductive agents and binders in proportion, adding solvents to obtain a slurry and coating it on aluminum foil, which is then dried, rolled and cut. The active material is sodium vanadium phosphate (Na3V2(PO4)3), sodium vanadium fluorophosphate (Na3V2(PO4)2F3) or sodium ferrous sulfate (Na2Fe(SO4)2), the conductive agent is conductive carbon black (SuperP), and the binder is polyvinylidene fluoride (PVDF). The mass ratio of the active material, conductive agent and binder is 90:6:4. The solvent is N-methylpyrrolidone (NMP). The negative electrode is a metal sodium sheet, and the diaphragm is a cellulose diaphragm.

[0088] In the present disclosure, the point values ​​listed above are merely for enumeration and are not limited thereto. Other point values ​​within the numerical range are applicable. To avoid complexity, they will not be described in detail here.

[0089] In the present disclosure, the above-mentioned normal temperature or room temperature refers to "20 to 30°C", and further refers to 25°C.

[0090] To further illustrate the present disclosure, the following examples are provided for detailed description. The experimental raw materials used in the following examples of the present disclosure are all commonly available commercial products.

[0091] Example 1

[0092] 1. Dissolve 11.4 g (0.1 mol) of vinyl compound A in 39.584 g (0.4 mol) of dichloroethane at -30 °C under argon atmosphere, and then heat it to room temperature at a heating rate of 3 °C / min to obtain a uniform solution;

[0093] 2. The solution containing the vinyl compound A was added to a stainless steel passivation reactor at liquid nitrogen temperature. The reactor temperature was controlled at -30°C. 16.4 g (0.2 mol) of CO2F2 was then condensed into the reactor. Copper foam was added as a catalyst to react with the vinyl compound A for 6 hours. The structure of the vinyl compound A is as follows:

[0094] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 12 h. The dichloroethane was removed by rotary evaporation at 40°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound I was isolated with a yield of 92.1% (yield = actual yield / theoretical yield). GC-MS (m / z): calcd. for C5F4N2O2, 196.06, found 195.99. The structure of Compound I is as follows:

[0095] 4. Dissolving the initiator azobisisobutyronitrile in compound I to prepare a polymerization precursor solution 1, wherein the mass proportion of azobisisobutyl group in the polymerization precursor solution 1 is 0.01%;

[0096] 5. A non-aqueous organic solvent, diethyl carbonate (DEC), and triethylene glycol divinyl ether were mixed in a mass ratio of 5:2 to prepare a mixed solvent. LiTFSI and an initiator, LiBF4, were added to the mixed solvent and fully dissolved to prepare a polymerization precursor solution II. The total mass of LiTFSI and the initiator, LiBF4, accounted for 30% and 3% of the total mass of the polymerization precursor solution II, respectively.

[0097] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:1. Maintain 500r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 0.5 h after mixing to prepare a polymer precursor electrolyte;

[0098] 7. Mix NCM811, conductive carbon, and PVDF in a weight ratio of 96:2:2 and ball mill for 24 hours. The solvent is NMP and the solid-liquid ratio is 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 6 hours. The active material surface density is controlled at 5 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0099] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0100] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify. The polymerization reaction formula of compound I is as follows:

[0101] The polymerization reactions of compounds II to X are similar, except that their branched chain structures are different.

[0102] The in-situ solid-state electrolyte obtained by solidification in this embodiment contains a large amount of F element, which greatly improves the voltage window of the electrolyte after polymerization. At the same time, the grafted functional group cyanide has a good complexing effect on transition metal ions such as cobalt ions, and can effectively inhibit the destruction of the positive electrode interface film caused by the dissolution of transition metal ions in the battery, thereby improving the stability of the positive electrode structure and enhancing the battery cycle stability.

[0103] Example 2

[0104] 1. Dissolve 38.4 g (0.3 mol) of vinyl compound B in 52.8 g (0.6 mol) of CF2CCl2 at -35°C and argon atmosphere, then heat for 2.5 min. -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0105] 2. The solution containing the vinyl compound B was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -30°C. 24.6 g (0.3 mol) of CO2F2 was then condensed into the reactor, and foamed iron was added as a catalyst to react with the vinyl compound B for 14 hours. The structure of the vinyl compound B is as follows:

[0106] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 18 hours. CF2CCl2 was then removed by rotary evaporation at 40°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound II was isolated with a yield of 93.3%. GC-MS (m / z): calcd. for C7F8N2O2, 296.08, found 295.98. The structure of Compound II is as follows:

[0107] 4. Dissolve the initiator methyl ethyl ketone peroxide in compound II to prepare a polymerization precursor solution 1, wherein the total mass proportion of the initiator in the polymerization precursor solution 1 is 0.2%;

[0108] 5. The non-aqueous organic solvent propylene carbonate (PC) and the monomer vinyl acetate are mixed in a mass ratio of 5:8 to prepare a mixed solvent, and LiFSI and the initiator LiPF6 are added to the above mixed solvent and fully dissolved to prepare a polymerization precursor solution II. The mass proportions of LiFSI and the initiator LiPF6 in the polymerization precursor solution II are 16% and 0.5%, respectively;

[0109] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 3 hours after mixing to prepare a polymer precursor electrolyte;

[0110] 7. Mix NCM811, conductive carbon, and PVDF in a weight ratio of 96:2:2 and ball mill for 20 hours. The solvent is NMP with a solid-liquid ratio of 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 6 hours. The active material surface density is controlled at 8 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0111] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0112] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify.

[0113] The in-situ solid electrolyte obtained by solidification in this embodiment contains rich F elements, which can effectively improve the oxidative stability of the electrolyte. At the same time, the presence of a large amount of F elements can also effectively enhance the flame retardant effect of the electrolyte, thereby improving the safety performance of the battery. The complexation of the functional group cyano with transition metal ions can stabilize the positive electrode CEI layer and protect the positive electrode structure. In addition, the trifluoromethyl group has good ionic conductivity and can provide a fluoride component that stabilizes the negative electrode SEI layer, thereby optimizing the stability of the SEI layer.

[0114] Example 3

[0115] 1. Dissolve 140.78 g (0.4 mol) of vinyl compound C in 70.4 g (0.8 mol) of CF2CCl2 at -35°C and argon atmosphere, then heat for 5 min. -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0116] 2. The solution containing the vinyl compound C was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -30°C. 98.4 g (1.2 mol) of CO2F2 was then condensed into the reactor, and foamed iron was added as a catalyst to react with the vinyl compound C for 20 hours. The structure of the vinyl compound C is as follows:

[0117] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 10 hours, and the CF2CCl2 was vaporized and discharged. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Finally, compound III was isolated with a yield of 91.8%. GC-MS (m / z): calcd. for C7H6F8O8S2, 434.22, found 433.94. The structure of compound III is as follows:

[0118] 4. Dissolve the initiator methyl ethyl ketone peroxide in compound III to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 2%;

[0119] 5. The non-aqueous organic solvent propylene carbonate (PC) and the monomer vinyl acetate were mixed in a mass ratio of 5:6 to prepare a mixed solvent, and LiFSI and the initiator LiPF6 were added to the above mixed solvent and fully dissolved to prepare a polymerization precursor solution II. The mass proportions of LiFSI and the initiator LiPF6 in the polymerization precursor solution II were 12% and 0.01%, respectively;

[0120] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:5. Maintain 600r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 2 h after mixing to prepare a polymer precursor electrolyte;

[0121] 7. LiFePO4, conductive carbon, and PVDF were mixed in a weight ratio of 96:2:2 and ball-milled for 18 hours. The solvent was NMP with a solid-liquid ratio of 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 10 hours. The active material surface density was controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0122] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0123] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0124] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing a sulfonic acid group. The rich F element can effectively improve the oxidative stability of the electrolyte. At the same time, the presence of a large amount of F element can also effectively enhance the flame retardant effect of the electrolyte, thereby improving the safety performance of the battery. The trifluoromethyl group has good ionic conductivity and can provide a stable fluoride component for the negative electrode SEI layer, thereby optimizing the stability of the SEI layer. At the same time, the grafted functional sulfonic acid group in the compound has a good complexing effect on lithium ions, which can effectively improve the ionic conductivity of the electrolyte.

[0125] Example 4

[0126] 1. Dissolve 108.4 g (0.4 mol) of vinyl compound D in 27.2 g (4.0 mol) of methanol at -40 °C and argon atmosphere, and then -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0127] 2. The solution containing the vinyl compound D was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -50°C. 49.2 g (0.6 mol) of CO2F2 was then condensed into the reactor, and nickel foam was added as a catalyst to react with the vinyl compound D for 16 hours. The structure of the vinyl compound D is as follows:

[0128] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 6 hours. Methanol was removed by rotary evaporation at 40°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound IV was isolated with a yield of 94.3%. GC-MS (m / z): calcd. for C5H6F4O8S2, 334.21, found 333.94. The structure of compound IV is as follows:

[0129] 4. Dissolving the initiator lauroyl peroxide in compound IV to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 1%;

[0130] 5. The non-aqueous organic solvent ethylene carbonate (EC) and the monomer ethyl vinyl sulfone were mixed in a mass ratio of 5:4 to prepare a mixed solvent, and LiTFSI and initiator LiPF6 were added to the above mixed solvent and fully dissolved to prepare a polymerization precursor solution II. The mass proportions of LiFSI and initiator LiPF6 in the polymerization precursor solution II were 15% and 2%, respectively;

[0131] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:4. Maintain 550r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 2.5 hours after mixing to prepare a polymer precursor electrolyte;

[0132] 7. LiFePO4, conductive carbon, and PVDF were mixed in a weight ratio of 96:2:2 and ball-milled for 14 hours. The solvent was NMP with a solid-liquid ratio of 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 8 hours. The active material surface density was controlled at 12 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0133] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0134] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 16 hours to solidify.

[0135] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing sulfonic acid groups. The rich F element can effectively improve the electrolyte's oxidative stability. The presence of a large amount of F element can also effectively enhance the electrolyte's flame retardancy, thereby improving battery safety. Furthermore, the presence of sulfonic acid groups can effectively improve the electrolyte's ionic conductivity.

[0136] Example 5

[0137] 1. Dissolve 133.0 g (0.5 mol) of vinyl compound E in 32.0 g (1 mol) of methanol at -40 °C and argon atmosphere, and then -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0138] 2. The solution containing the vinyl compound E was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -45°C. 164.0 g (2 mol) of CO2F2 was then condensed into the reactor, and nickel foam was added as a catalyst to react with the vinyl compound E for 27 hours. The structure of the vinyl compound E is as follows:

[0139] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 8 hours. Methanol was removed by rotary evaporation at 40°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound V was isolated with a yield of 92.1%. GC-MS (m / z): calcd. for C7H6F2N2O8S2, 348.25, found 347.95. The structure of compound V is as follows:

[0140] 4. Dissolving the initiator lauroyl peroxide in compound V to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 5%;

[0141] 5. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethyl vinyl sulfone, are mixed in a mass ratio of 5:10 to prepare a mixed solvent. LiTFSI and an initiator, FeCl3, are dissolved in the mixed solution until fully dissolved to prepare a second polymerization precursor solution. The mass proportions of LiTFSI and the initiator, FeCl3, in the second polymerization precursor solution are 30% and 2%, respectively.

[0142] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:1. Maintain 550r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0143] 7. LCO, conductive carbon, and PVDF were mixed in a weight ratio of 96:2:2 and ball-milled for 12 hours. The solvent was NMP with a solid-liquid ratio of 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 7 hours. The active material surface density was controlled at 15 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0144] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0145] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 42 hours to solidify.

[0146] The in-situ solid-state electrolyte obtained by curing in this embodiment uses a fluorinated 1,3-dioxolane compound containing sulfonic acid and cyano groups. The presence of the F element imparts high oxidative stability to the electrolyte, while also providing a certain degree of flame retardancy. Furthermore, the functional cyano groups effectively complex transition metal ions, protecting the positive electrode structure, while the sulfonic acid groups effectively suppress and improve the electrolyte's ionic conductivity.

[0147] Example 6

[0148] 1. Dissolve 162.5 g (0.7 mol) of vinyl compound F in 467.25 g (3.5 mol) of chloroform at -45 °C and argon atmosphere, then heat at 1.0 °C min -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0149] 2. The solution containing the vinyl compound F was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -30°C. 57.4 g (0.7 mol) of CO2F2 was then condensed into the reactor, and copper foam was added as a catalyst to react with the vinyl compound F for 48 hours. The structural formula of the vinyl compound F is as follows:

[0150] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 16 hours. Chloroform was removed by rotary evaporation at 50°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound VI was isolated with a yield of 93.1%. GC-MS (m / z): calcd. for C 11 H 24 F2O 10 S2Si2,474.59,found474.03, the structure of compound VI is as follows:

[0151] 4. Dissolve the initiator azobisisobutyronitrile in compound VI to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 1.2%;

[0152] 5. A non-aqueous organic solvent, ethyl methyl carbonate (EMC), and a monomer, methyl vinyl sulfone, were prepared as a mixed solvent in a mass ratio of 5:7. LiTFSI and an initiator, LiODFB, were dissolved in the mixed solvent to prepare a second polymerization precursor solution. The mass proportions of LiTFSI and the initiator, LiODFB, in the second polymerization precursor solution were 25% and 2%, respectively.

[0153] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:1.5. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 2.0 h after mixing to prepare a polymer precursor electrolyte;

[0154] 7. Mix NCM622, conductive carbon, and PVDF in a weight ratio of 96:2:2 and ball mill for 24 hours. The solvent is NMP with a solid-liquid ratio of 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 6 hours. The active material surface density is controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0155] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0156] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 40 hours to solidify.

[0157] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing a trimethylsiloxane functional group. While the F element improves the oxidative stability of the electrolyte after polymerization, the solid electrolyte contains trimethylsiloxane functional groups, which can remove excess HF in the polymerization precursor electrolyte and inhibit excessive gas production in the battery during the electrochemical process. In addition, trimethylsiloxane has excellent stability and has a certain flame retardant effect on the battery. The sulfonic acid group has a good complexing ability for lithium ions, which makes the electrolyte have good ionic conductivity.

[0158] Example 7

[0159] 1. Dissolve 50.82 g (0.2 mol) of vinyl compound G in 119.4 g (1 mol) of chloroform at -45 °C and argon atmosphere, then heat for 5 min. -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0160] 2. The solution containing the vinyl compound G was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -30°C. 82.0 g (1 mol) of CO2F2 was then condensed into the reactor, and copper foam was added as a catalyst to react with the vinyl compound G for 12 hours. The structural formula of the vinyl compound G is as follows:

[0161] 3. Under an argon atmosphere, the heating rate was controlled to allow the reactor to reach room temperature within 27 hours. Chloroform was removed by rotary evaporation at 35°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound VII was isolated with a yield of 92.1%. GC-MS (m / z): calcd. for C 13 H 24 F2O8Si2,402.49found402.10,, the structure of compound VII is as follows:

[0162] 4. Dissolve the initiator azobisisobutyronitrile in compound VII to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 0.1%;

[0163] 5. A non-aqueous organic solvent, ethyl methyl carbonate (EMC), and a monomer, n-butyl methacrylate, were mixed in a mass ratio of 5:3 to prepare a mixed solvent. LiTFSI and an initiator, LiODFB, were dissolved in the mixed solvent to prepare a second polymerization precursor solution. The mass proportions of LiTFSI and the initiator, LiODFB, in the second polymerization precursor solution were 20% and 0.6%, respectively.

[0164] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:2. Maintain 400r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 0.5 h after mixing to prepare a polymer precursor electrolyte;

[0165] 7. Lithium iron phosphate (LiFePO4), conductive carbon, and PVDF were mixed in a weight ratio of 96:2:2 and ball-milled for 20 hours. The solvent was NMP with a solid-liquid ratio of 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 8 hours. The active material surface density was controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0166] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0167] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 60 hours to solidify.

[0168] The in-situ solid-state electrolyte obtained by curing in this embodiment uses a fluorinated 1,3-dioxolane compound containing trimethylsiloxane and carboxylic acid functional groups. This not only effectively improves the oxidative stability of the electrolyte after polymerization, but its rich functional group trimethylsiloxane can remove excess HF from the polymerization precursor electrolyte, inhibiting excessive gas production during the battery's electrochemical process. At the same time, its excellent structural stability can improve the stability of the electrolyte and has a certain flame retardant effect. In addition, the carboxylic acid groups contained in this solid electrolyte have a good complexation effect with lithium, which can effectively improve the electrolyte's ionic conductivity.

[0169] Example 8

[0170] 1. Dissolve 58.2 g (0.3 mol) of vinyl compound H in 34.8 g (0.6 mol) of acetone at -25 °C and argon atmosphere, then heat for 2 min at 2 °C. -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0171] 2. The solution containing the vinyl compound H was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -25°C. 49.2 g (0.6 mol) of CO2F2 was then condensed into the reactor, and foamed iron was added as a catalyst to react with the vinyl compound H for 15 hours. The structural formula of the vinyl compound H is as follows:

[0172] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 12 hours. Acetone was removed by rotary evaporation at 45°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound VIII was isolated with a yield of 94.1%. GC-MS (m / z): calcd. for C9H6F2N2O6, 276.15, found 276.02. The structure of compound VIII is as follows:

[0173] 4. Dissolve the initiator azobisisobutyronitrile in compound VIII to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 0.2%;

[0174] 5. A non-aqueous organic solvent, ethylene glycol dimethyl ether (DME), and a monomer, triethylene glycol divinyl ether, were mixed in a mass ratio of 5:1 to prepare a mixed solvent. LiTFSI and an initiator, LiPF6, were added to the mixed solvent and fully dissolved to prepare a second polymerization precursor solution. The mass proportions of LiFSI and the initiator, LiPF6, in the second polymerization precursor solution were 26% and 2%, respectively.

[0175] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0176] 7. Mix NCM811, conductive carbon, and PVDF in a weight ratio of 96:2:2 and ball mill for 24 hours. The solvent is NMP with a solid-liquid ratio of 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 12 hours. The active material surface density is controlled at 12 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0177] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0178] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 72 hours to solidify.

[0179] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing carboxylate and cyano functional groups. While having high oxidative stability, the rich carboxylate functional groups have good complexing ability for lithium ions, which can effectively improve the ionic conductivity of the electrolyte. In addition, its functional functional group cyano has good complexing ability for transition metal ions, which can effectively inhibit the damage to the stability of the positive electrode caused by the dissolution of transition metal ions.

[0180] Example 9

[0181] 1. Dissolve 68.8 g (0.4 mol) of vinyl compound I in 129.8 g (1.8 mol) of methyl ethyl ketone at -40 °C and argon atmosphere, and then -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0182] 2. The solution containing the vinyl compound I was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -40°C. 82.0 g (1 mol) of CO2F2 was then condensed into the reactor, and foam was added as a catalyst to react with the vinyl compound I for 18 hours. The structural formula of the vinyl compound I is as follows:

[0183] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 48 hours. Methyl ethyl ketone was removed by rotary evaporation at 40°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound IX was isolated with a yield of 95.0%. GC-MS (m / z): calcd. for C9H 12 F2O6, 254.19, found 254.06, the structure of compound IX is as follows:

[0184] 4. Dissolve the initiator azobisisobutyronitrile in compound IX to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 1%;

[0185] 5. The non-aqueous organic solvent diethyl carbonate (DEC) and the monomer trimethylolpropane triacrylate were mixed in a mass ratio of 5:2 to prepare a mixed solvent, and LiFSI and initiator LiBF4 were added to the mixed solvent to prepare a polymerization precursor solution II. The mass proportions of LiFSI and initiator LiBF4 in the polymerization precursor solution II were 22% and 0.05%, respectively;

[0186] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3.5. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 3 hours after mixing to prepare a polymer precursor electrolyte;

[0187] 7. LiFePO4, conductive carbon, and PVDF were mixed in a weight ratio of 90:6:4 and ball-milled for 72 hours. The solvent was NMP with a solid-liquid ratio of 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 24 hours. The active material surface density was controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0188] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0189] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 12 hours to solidify.

[0190] The in-situ solid-state electrolyte obtained by solidification in this embodiment utilizes a fluorinated 1,3-dioxolane compound containing a carboxylate group. The presence of the F element imparts high oxidative stability to the electrolyte and also provides a certain degree of flame retardancy. The abundant carboxylate functional groups exhibit excellent complexing properties for lithium and sodium ions, effectively enhancing the electrolyte's ionic conductivity.

[0191] Example 10

[0192] 1. Dissolve 140.0 g (0.5 mol) of vinyl compound J in 144.2 g (2.0 mol) of methyl ethyl ketone at -50 °C and argon atmosphere, and then -1 The solution was heated to room temperature at a heating rate of 100 nm to obtain a homogeneous solution.

[0193] 2. The solution containing the vinyl compound J was added to a stainless steel passivation reactor at liquid nitrogen temperature, with the reactor temperature controlled at -40°C. 123.0 g (1.5 mol) of CO2F2 was then condensed into the reactor, and foam was added as a catalyst to react with the vinyl compound J for 24 hours. The structural formula of the vinyl compound J is as follows:

[0194] 3. Under an argon atmosphere, the heating rate was controlled so that the reactor reached room temperature within 12 hours. Methyl ethyl ketone was removed by rotary evaporation at 40°C. The product was purified by silica gel chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1 as the eluent. Compound X was isolated with a yield of 95.1%. GC-MS (m / z): calcd. for C9H6F8O6, 362.13, found 362.00. The structure of compound X is as follows:

[0195] 4. Dissolve the initiator azobisisobutyronitrile in compound X to prepare a polymerization precursor solution 1, wherein the mass of azobisisobutyronitrile is 0.04% of the mass of the polymerization precursor solution 1;

[0196] 5. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:1 to prepare a mixed solvent, and LiFSI and an initiator, LiBF4, were dissolved in the mixed solution to prepare a polymerization precursor solution II, wherein the total mass proportions of LiFSI and the initiator, LiBF4, in the polymerization precursor solution II were 16% and 0.05%, respectively;

[0197] 6. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3. Maintain 400r min during the mixing process. -1The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0198] 7. LiFePO4, conductive carbon, and PVDF were mixed in a weight ratio of 96:2:2 and ball-milled for 12 hours. The solvent was NMP with a solid-liquid ratio of 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 6 hours. The active material surface density was controlled at 8 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0199] 8. Assemble the steel sheet||diaphragm||steel sheet, and conduct ion conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing.

[0200] 9. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0201] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing carboxylate and trifluoromethyl functional groups. The rich F element can effectively improve the electrolyte's oxidative stability. The presence of a large amount of F also effectively enhances the electrolyte's flame retardancy, thereby improving battery safety. The grafted trifluoromethyl group has good ionic conductivity and can provide a fluoride component that stabilizes the negative electrode SEI layer, optimizing the stability of the SEI layer.

[0202] Example 11

[0203] 1. Compounds I and IV were mixed in a mass ratio of 1:1 to prepare a mixed solvent 1. The initiator azobisisobutyronitrile was dissolved in the mixed solvent 1 to prepare a polymerization precursor solution 1. The mass of azobisisobutyronitrile was 0.04% of the mass of the polymerization precursor solution 1.

[0204] 2. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:1 to prepare a mixed solvent, and LiTFSI and an initiator, LiBF4, were dissolved in the mixed solution to prepare a second polymerization precursor solution, wherein the total mass proportions of LiTFSI and the initiator, LiBF4, in the second polymerization precursor solution were 16% and 0.1%, respectively;

[0205] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:4. Maintain 700r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0206] 4. The preparation of electrodes and assembly of button cells are the same as in Example 10. The polymer precursor electrolyte is injected into each battery and allowed to stand at room temperature for 20 hours to solidify. The in-situ solid-state electrolyte obtained by solidification in this embodiment adopts a copolymer of a fluorinated-1,3-dioxolane compound containing cyano and sulfonic acid functional groups. The rich F element can effectively improve the oxidative stability of the electrolyte. At the same time, the presence of a large amount of F element can also effectively enhance the flame retardant effect of the electrolyte, thereby improving the safety performance of the battery. At the same time, the rich cyano group has a good complexing effect on transition metal ions such as cobalt ions, which can effectively inhibit the problem of positive electrode interface film destruction caused by the dissolution of transition metal ions in the excessive gas production of the battery during the electrochemical process, thereby improving the structural stability of the positive electrode and improving the cycle stability of the battery. The sulfonic acid functional group has a good complexing effect on lithium / sodium ions, which can effectively improve the ionic conductivity of the electrolyte.

[0207] Example 12

[0208] 1. Dissolve the initiator azobisisobutyronitrile in compound I to prepare a polymerization precursor solution 1, wherein the mass proportion of azobisisobutyl group in the polymerization precursor solution 1 is 0.01%;

[0209] 2. A non-aqueous organic solvent, diethyl carbonate (DEC), and triethylene glycol divinyl ether were mixed in a mass ratio of 5:2 to prepare a mixed solvent, and NaClO4 and an initiator, NaBF4, were added to the mixed solvent and fully dissolved to prepare a second polymerization precursor solution. The total mass proportions of NaClO4 and the initiator, NaBF4, in the second polymerization precursor solution were 30% and 3%, respectively;

[0210] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:1. Maintain 500r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 0.5 h after mixing to prepare a polymer precursor electrolyte;

[0211] 4. Sodium phosphate (Na3V2(PO4)3), conductive carbon, and PVDF were mixed in a weight ratio of 90:6:4 and ball-milled for 20 hours. The solvent was NMP, and the solid-liquid ratio was 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 8 hours. The active material surface density was controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0212] 5. Assemble the steel sheet||diaphragm||steel sheet, and conduct ionic conductivity test on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||sodium metal, with sodium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window test. Assemble the half-cell with positive electrode||diaphragm||sodium metal negative electrode and conduct charge and discharge test.

[0213] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 16 hours to solidify;

[0214] The in-situ solid-state electrolyte obtained by solidification in this embodiment contains a large amount of F element, which greatly improves the voltage window of the electrolyte after polymerization. At the same time, the grafted functional group cyanide has a good complexing effect on transition metal ions such as cobalt ions, and can effectively inhibit the destruction of the positive electrode interface film caused by the dissolution of transition metal ions in the battery, thereby improving the stability of the positive electrode structure and enhancing the battery cycle stability.

[0215] Example 13

[0216] 1. Dissolve the initiator azobisisobutyronitrile in compound II to prepare a polymerization precursor solution 1, where the mass proportion of the initiator in the polymerization precursor solution 1 is 0.1%;

[0217] 2. A non-aqueous organic solvent, ethyl methyl carbonate (EMC), and a monomer, n-butyl methacrylate, were mixed in a mass ratio of 5:3 to prepare a mixed solvent. NaClO4 and an initiator, NaODFB, were added to the mixed solvent and fully dissolved to prepare a second polymerization precursor solution. The mass proportions of NaClO4 and the initiator, NaODFB, in the second polymerization precursor solution were 20% and 0.6%, respectively.

[0218] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:2. Maintain 400r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 0.5 h after mixing to prepare a polymer precursor electrolyte;

[0219] 4. The positive electrode uses sodium sulfate (Na3V2(PO4)3), and the electrode preparation and battery assembly are the same as in Example 12;

[0220] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0221] The in-situ solid electrolyte obtained by solidification in this embodiment contains a rich amount of F element, which can effectively improve the oxidative stability of the electrolyte. At the same time, the presence of a large amount of F element can also effectively enhance the flame retardant effect of the electrolyte, thereby improving the safety performance of the battery. The complexation of the functional group cyano with the transition metal ions can stabilize the positive electrode CEI layer and protect the positive electrode structure. In addition, the trifluoromethyl group has good ionic conductivity and can provide a fluoride component that stabilizes the negative electrode SEI layer, thereby optimizing the stability of the SEI layer.

[0222] Example 14

[0223] 1. Dissolve the initiator azobisisobutyronitrile in compound III to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 0.2%;

[0224] 2. A non-aqueous organic solvent, ethylene glycol dimethyl ether (DME), and a monomer, triethylene glycol divinyl ether, were mixed in a mass ratio of 5:1 to prepare a mixed solvent. NaClO4 and an initiator, NaBF4, were added to the mixed solvent and fully dissolved to prepare a second polymerization precursor solution. The mass proportions of NaClO4 and the initiator, NaBF4, in the second polymerization precursor solution were 26% and 2%, respectively.

[0225] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0226] 4. The positive electrode uses sodium vanadium phosphate (Na3V2(PO4)3). The electrode preparation method is the same as that in Example 12, except that the active material surface density is controlled at 12 mg cm -2 ;

[0227] 5. The button battery assembly method is the same as that of Example 12;

[0228] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 72 hours to solidify.

[0229] The in-situ solid electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing a sulfonic acid group. The rich F element can effectively improve the oxidative stability of the electrolyte. At the same time, the presence of a large amount of F element can also effectively enhance the flame retardant effect of the electrolyte, thereby improving the safety performance of the battery. The trifluoromethyl group has good ionic conductivity and can provide a stable fluoride component for the negative electrode SEI layer, thereby optimizing the stability of the SEI layer. At the same time, the grafted functional sulfonic acid group in the compound has a good complexing effect on sodium ions, which can effectively improve the ionic conductivity of the electrolyte.

[0230] Example 15

[0231] 1. Dissolve the initiator azobisisobutyronitrile in compound IV to prepare a polymerization precursor solution 1, wherein the mass proportion of the initiator in the polymerization precursor solution 1 is 1%;

[0232] 2. The non-aqueous organic solvent diethyl carbonate (DEC) and the monomer trimethylolpropane triacrylate were mixed in a mass ratio of 5:2 to prepare a mixed solvent, and NaFSI and initiator NaBF4 were added to the mixed solvent to prepare a polymerization precursor solution II. The mass proportions of NaFSI and initiator NaBF4 in the polymerization precursor solution II were 22% and 0.05%, respectively;

[0233] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3.5. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and continued to be stirred for 3 hours after mixing to prepare a polymer precursor electrolyte;

[0234] 4. Sodium vanadium fluorophosphate (Na3V2(PO4)2F3), conductive carbon, and PVDF were mixed in a weight ratio of 90:6:4 and ball-milled for 72 hours. The solvent was NMP, and the solid-liquid ratio was 45%. The resulting slurry was coated on the surface of aluminum foil and dried at 110°C for 24 hours. The active material surface density was controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0235] 5. The button battery assembly method is the same as that of Example 12;

[0236] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 12 hours to solidify.

[0237] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing sulfonic acid groups. The rich F element can effectively improve the electrolyte's oxidative stability. The presence of a large amount of F element can also effectively enhance the electrolyte's flame retardancy, thereby improving battery safety. Furthermore, the presence of sulfonic acid groups can effectively improve the electrolyte's ionic conductivity.

[0238] Example 16

[0239] 1. Dissolve the initiator azobisisoheptanonitrile in compound V to prepare a polymerization precursor solution 1, wherein the mass of azobisisoheptanonitrile is 0.04% of the mass of the polymerization precursor solution 1;

[0240] 2. A non-aqueous organic solvent, propylene carbonate (PC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:1 to prepare a mixed solvent, and NaFSI and an initiator, NaBF4, were dissolved in the mixed solution to prepare a second polymerization precursor solution, wherein the total mass proportions of NaFSI and the initiator, NaBF4, in the second polymerization precursor solution were 16% and 0.05%, respectively;

[0241] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3. Maintain 400r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0242] 4. The positive electrode uses sodium vanadium fluorophosphate (Na3V2(PO4)2F3). The electrode preparation method is the same as that in Example 15, except that the active material surface density is controlled at 8 mg cm -2 ;

[0243] 5. The button battery assembly method is the same as that of Example 12;

[0244] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0245] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing sulfonic acid groups. The rich F element can effectively improve the electrolyte's oxidative stability. The presence of a large amount of F element can also effectively enhance the electrolyte's flame retardancy, thereby improving battery safety. Furthermore, the presence of sulfonic acid groups can effectively improve the electrolyte's ionic conductivity.

[0246] Example 17

[0247] 1. Dissolve the initiator lauroyl peroxide in compound VI to prepare a polymerization precursor solution 1, wherein the mass of lauroyl peroxide is 0.2% of the mass of the polymerization precursor solution 1;

[0248] 2. A non-aqueous organic solvent, propylene carbonate (PC), and a monomer, vinyl acetate, were mixed in a mass ratio of 5:8 to prepare a mixed solvent, and NaFSI and an initiator, NaBF4, were dissolved in the mixed solution to prepare a second polymerization precursor solution, wherein the total mass proportions of NaFSI and the initiator, NaBF4, in the second polymerization precursor solution were 16% and 0.5%, respectively;

[0249] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3. Maintain 700r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.5 hours after mixing to prepare a polymer precursor electrolyte;

[0250] 4. The positive electrode uses sodium ferric sulfate (Na2Fe(SO4)2). The electrode preparation method is the same as that in Example 12, except that the active material surface density is controlled at 8 mg cm -2 ;

[0251] 5. The button battery assembly method is the same as that of Example 12;

[0252] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify.

[0253] The in-situ solid-state electrolyte obtained by solidification in this embodiment uses a fluorinated 1,3-dioxolane compound containing a trimethylsiloxane functional group. While the F element improves the oxidative stability of the electrolyte after polymerization, the solid electrolyte contains trimethylsiloxane functional groups, which can remove excess HF in the polymerization precursor electrolyte and inhibit excessive gas production in the battery during the electrochemical process. In addition, trimethylsiloxane has excellent stability and has a certain flame retardant effect on the battery. The sulfonic acid group has a good complexing ability for sodium ions, which makes the electrolyte have good ionic conductivity.

[0254] Example 18

[0255] 1. Dissolve the initiator methyl ethyl ketone peroxide in compound VII to prepare a polymerization precursor solution 1, wherein the mass of methyl ethyl ketone peroxide is 2% of the mass of the polymerization precursor solution 1;

[0256] 2. A non-aqueous organic solvent, propylene carbonate (PC), and a monomer, vinyl acetate, were mixed in a mass ratio of 5:8 to prepare a mixed solvent, and NaFSI and an initiator, NaBF4, were dissolved in the mixed solution to prepare a second polymerization precursor solution, wherein the total mass proportions of NaFSI and the initiator, NaBF4, in the second polymerization precursor solution were 12% and 0.01%, respectively;

[0257] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:5. Maintain 600r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 2 h after mixing to prepare a polymer precursor electrolyte;

[0258] 4. Sodium ferric sulfate (Na2Fe(SO4)2) was used as the positive electrode, and the electrode preparation method was the same as in Example 12;

[0259] 5. The button battery assembly method is the same as that of Example 12;

[0260] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 22 hours to solidify.

[0261] The in-situ solid-state electrolyte obtained by curing in this embodiment uses a fluorinated 1,3-dioxolane compound containing trimethylsiloxane and carboxylic acid functional groups. This not only effectively improves the oxidative stability of the electrolyte after polymerization, but its rich functional group trimethylsiloxane can remove excess HF in the polymerization precursor electrolyte, inhibiting excessive gas production during the battery's electrochemical process. At the same time, its excellent structural stability can improve the stability of the electrolyte and has a certain flame retardant effect. In addition, the carboxylic acid groups contained in this solid electrolyte have a good complexation effect with sodium ions, which can effectively improve the electrolyte ion conductivity.

[0262] Example 19

[0263] 1. Dissolve the initiator azobisisobutyronitrile in compound VIII to prepare a polymerization precursor solution 1, wherein the mass of azobisisobutyronitrile is 2% of the mass of the polymerization precursor solution 1;

[0264] 2. A non-aqueous organic solvent, propylene carbonate (PC), and a monomer, vinyl acetate, were mixed in a mass ratio of 5:8 to prepare a mixed solvent, and NaFSI and an initiator, NaBF4, were dissolved in the mixed solution to prepare a second polymerization precursor solution, wherein the total mass proportions of NaFSI and the initiator, NaBF4, in the second polymerization precursor solution were 12% and 0.01%, respectively;

[0265] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:5. Maintain 600r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 2 h after mixing to prepare a polymer precursor electrolyte;

[0266] 4. Sodium ferric sulfate (Na2Fe(SO4)2) was used as the positive electrode, and the electrode preparation method was the same as in Example 12;

[0267] 5. The button battery assembly method is the same as that of Example 12;

[0268] 6. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 22 hours to solidify.

[0269] The in-situ solid-state electrolyte solidified in this embodiment uses a fluorinated 1,3-dioxolane compound containing carboxylate and cyano functional groups. While having high oxidative stability, the rich carboxylate functional groups have good complexing ability for sodium ions, which can effectively improve the ionic conductivity of the electrolyte. In addition, its functional functional group cyano has good complexing ability for transition metal ions, which can effectively inhibit the damage to the stability of the positive electrode caused by the dissolution of transition metal ions.

[0270] Example 20

[0271] 1. Dissolve the initiator methyl ethyl ketone peroxide in compound VI to prepare a polymerization precursor solution 1, wherein the mass of methyl ethyl ketone peroxide is 1.2% of the mass of the polymerization precursor solution 1;

[0272] 2. A non-aqueous organic solvent, propylene carbonate (PC), and a monomer, methyl vinyl sulfone, were prepared as a mixed solvent in a mass ratio of 5:7. LiTFSI and an initiator, LiODFB, were dissolved in the mixed solvent to prepare a second polymerization precursor solution. The mass proportions of LiTFSI and the initiator, LiODFB, in the second polymerization precursor solution were 25% and 2%, respectively.

[0273] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:1.5. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 2.0 h after mixing to prepare a polymer precursor electrolyte;

[0274] 4. The positive electrode material NCM811, the conductive agent carbon black (SuperP), and the binder polyvinylidene fluoride (PVDF, NMP solution with a content of 5% by mass) were weighed and mixed in a mass ratio of 96.5:1.5:2. After mixing, an appropriate amount of NMP was added to control the theoretical solid content to 55%. The positive electrode slurry was homogenized using a vacuum defoamer to obtain a positive electrode slurry, and the positive electrode slurry was evenly coated on a 17 μm thick aluminum foil. After drying, rolling, and cutting, a 50 mm × 70 mm positive electrode sheet was obtained;

[0275] 5. Mix the negative electrode material artificial graphite, the conductive agent SuperP, the thickener sodium carboxymethyl cellulose (CMC, 1.5% by mass in deionized water), and the binder styrene-butadiene rubber (SBR, 48% by mass in deionized water) in a mass ratio of 95:1:1.5:2.5. After mixing, add deionized water to control the theoretical solid content to 52%. Use a vacuum defoamer to homogenize to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on a 17μm thick copper foil. After drying, rolling, and cutting, a 52mm×72mm negative electrode sheet is obtained. The N / P ratio of the positive and negative electrodes is 1.1;

[0276] 6. Cut the polyethylene diaphragm into 55mm×75mm size and bake it in vacuum at 70℃ for 48h to remove water;

[0277] 7. Under an ambient dew point of ≤-45°C, produce soft-pack laminated batteries. Stack the positive electrode, separator, and negative electrode in order, with the positive and negative tabs on the same side and the separator between the positive and negative electrodes to provide isolation. This produces a bare cell. Place the bare cell in an aluminum-plastic film outer package, vacuum bake at 90°C for 12 hours, cool to below 40°C, and inject the prepared polymer precursor electrolyte. Then, proceed with packaging, impregnation, formation, aging, secondary vacuum packaging, and capacity grading.

[0278] Example 21

[0279] 1. Dissolve the initiator azobisisobutyronitrile in compound VII to prepare a polymerization precursor solution 1, wherein the mass of azobisisobutyronitrile is 0.1% of the mass of the polymerization precursor solution 1;

[0280] 2. A non-aqueous organic solvent, propylene carbonate (PC), and a monomer, methyl methacrylate, were prepared as a mixed solvent in a mass ratio of 5:3. LiTFSI and an initiator, LiBF4, were dissolved in the mixed solvent to prepare a second polymerization precursor solution. The mass proportions of LiTFSI and the initiator, LiBF4, in the second polymerization precursor solution were 20% and 0.6%, respectively.

[0281] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:2. Maintain 800r min during the mixing process. -1 The mixture was stirred at a high speed and stirred for 1.0 h after mixing to prepare a polymer precursor electrolyte;

[0282] 4. The battery preparation and testing methods are the same as in Example 20.

[0283] Comparative Example 1

[0284] 1. The electrolyte solvent dimethyl carbonate (DMC) and ethylene carbonate (EC) are mixed in a mass ratio of 4:3 to prepare a mixed solvent, and LiTFSI and initiator LiPF6 are dissolved in the above mixed solvent and fully dissolved to prepare a basic electrolyte containing the initiator, wherein the total mass proportions of the mixed solvent, LiTFSI and initiator LiPF6 in the basic electrolyte are 69%, 30% and 1% respectively;

[0285] 2. Add the basic electrolyte containing initiator described in step 1 to DOL gradually. The mass ratio of basic electrolyte to DOL is 1:2. During the mixing process, the polymerization precursor solution is kept at 600 r min. -1 The mixture was stirred at a high speed and stirred for 1 hour after mixing to prepare a polymer precursor electrolyte;

[0286] 3. Mix NCM811, conductive carbon, and PVDF in a weight ratio of 90:6:4 and ball mill for 24 hours. The solvent is NMP with a solid-liquid ratio of 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 6 hours. The active material surface density is controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0287] 4. Assemble steel sheet||diaphragm||steel sheet, and conduct ion conductivity test on the battery with blocking electrodes on both sides; assemble steel sheet||diaphragm||lithium metal, with lithium metal as the reference electrode and counter electrode and steel sheet as the working electrode, and conduct voltage window test. Assemble half-cell with positive electrode||diaphragm||lithium metal negative electrode for charge and discharge test;

[0288] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0289] Comparative Example 2

[0290] 1. Dissolve the initiator azobisisobutyronitrile in 1,3-dioxolane (DOL) to prepare a polymerization precursor solution 1, wherein the mass fraction of the initiator in the polymerization precursor solution 1 is 0.2%;

[0291] 2. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:2 to prepare a mixed solvent. LiTFSI and an initiator, LiBF4, were added to the mixed solvent to prepare a second polymerization precursor solution. The mass fractions of LiTFSI and the initiator, LiBF4, in the second polymerization precursor solution were 23% and 0.05%, respectively.

[0292] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3.5. During the mixing process, the polymerization precursor solution is kept at 500 r min. -1 The mixture was stirred at a high speed and continued to be stirred for 3 hours after mixing to prepare a polymer precursor electrolyte;

[0293] 4. The electrode preparation and battery assembly test methods are the same as those in Comparative Example 1;

[0294] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0295] Comparative Example 3

[0296] 1. The electrolyte solvent dimethyl carbonate (DMC) and ethylene carbonate (EC) are mixed in a mass ratio of 4:3 to prepare a mixed solvent, and LiTFSI and initiator LiPF6 are dissolved in the above mixed solvent and fully dissolved to prepare a basic electrolyte containing the initiator, wherein the total mass proportions of the mixed solvent, LiTFSI and initiator LiPF6 in the basic electrolyte are 69%, 30% and 1% respectively;

[0297] 2. Add the initiator-containing basic electrolyte described in step 1 to perfluoro-1,3-dioxolane in a 1:2 mass ratio. During the mixing process, the polymerization precursor solution is kept at 1200 r min. -1 The mixture was stirred at a high speed and stirred for 1 hour after mixing to prepare a polymer precursor electrolyte;

[0298] 3. The electrode preparation and battery assembly methods are the same as those in Comparative Example 1;

[0299] 4. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify.

[0300] Comparative Example 4

[0301] 1. Dissolve the initiator azobisisobutyronitrile in perfluoro-1,3-dioxolane to prepare a polymerization precursor solution 1, where the mass fraction of the initiator in the polymerization precursor solution 1 is 0.2%;

[0302] 2. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:2 to prepare a mixed solvent. LiTFSI and an initiator, LiBF4, were added to the mixed solvent to prepare a second polymerization precursor solution. The mass fractions of LiTFSI and the initiator, LiBF4, in the second polymerization precursor solution were 23% and 0.05%, respectively.

[0303] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3.5. During the mixing process, the polymerization precursor solution is kept at 500 r min. -1 The mixture was stirred at a high speed and continued to be stirred for 3 hours after mixing to prepare a polymer precursor electrolyte;

[0304] 4. The electrode preparation and battery assembly methods are the same as those in Comparative Example 1;

[0305] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0306] Comparative Example 5

[0307] 1. The electrolyte solvents dimethyl carbonate (DMC) and ethylene carbonate (EC) were mixed in a mass ratio of 4:3 to prepare a mixed solvent, and the lithium salt LiTFSI was dissolved in the above mixed solvent until fully dissolved to prepare a comparative electrolyte 5, wherein the total mass fractions of the mixed solvent and LiTFSI in the electrolyte were 87% and 13% respectively;

[0308] 2. Mix NCM811, conductive carbon, and PVDF in a weight ratio of 90:6:4 and ball mill for 24 hours. The solvent is NMP with a solid-liquid ratio of 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 6 hours. The active material surface density is controlled at 15 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0309] 3. Assemble a half-cell by using the positive electrode||diaphragm||lithium metal negative electrode for charge and discharge testing;

[0310] 4. Inject comparative electrolyte 5 into the battery and let it stand at room temperature for 12 hours before testing.

[0311] Comparative Example 6

[0312] 1. The electrolyte solvent dimethyl carbonate (DMC) and ethylene carbonate (EC) are mixed in a mass ratio of 4:3 to prepare a mixed solvent, and NaTFSI and initiator NaPF6 are dissolved in the above mixed solvent and fully dissolved to prepare a basic electrolyte containing the initiator, wherein the total mass proportions of the mixed solvent, NaTFSI and initiator NaPF6 in the basic electrolyte are 69%, 30% and 1% respectively;

[0313] 2. Add the basic electrolyte containing initiator described in step 1 to DOL gradually. The mass ratio of basic electrolyte to DOL is 1:2. During the mixing process, the polymerization precursor solution is kept at 600 r min. -1 The mixture was stirred at a high speed and stirred for 1 hour after mixing to prepare a polymer precursor electrolyte;

[0314] 3. Mix Na3V2(PO4)3, conductive carbon, and PVDF in a weight ratio of 90:6:4 and ball mill for 24 hours. The solvent is NMP with a solid-liquid ratio of 45%. The resulting slurry is coated on the surface of aluminum foil and air-dried at 110°C for 6 hours. The active material surface density is controlled at 10 mg cm -2 . 12mm positive electrode discs are obtained by cutting;

[0315] 4. Assemble the steel sheet||diaphragm||steel sheet, and conduct ionic conductivity testing on the battery with blocking electrodes on both sides. Assemble the steel sheet||diaphragm||sodium metal, using sodium metal as the reference electrode and counter electrode and the steel sheet as the working electrode, and conduct voltage window testing. Assemble the half-cell with the positive electrode||diaphragm||sodium metal negative electrode for charge and discharge testing.

[0316] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify.

[0317] Comparative Example 7

[0318] 1. Dissolve the initiator azobisisobutyronitrile in 1,3-dioxolane (DOL) to prepare a polymerization precursor solution 1, wherein the mass fraction of the initiator in the polymerization precursor solution 1 is 0.2%;

[0319] 2. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:2 to prepare a mixed solvent. NaFSI and an initiator, NaODFB, were added to the mixed solvent to prepare a second polymerization precursor solution. The mass fractions of NaFSI and the initiator, NaODFB, in the second polymerization precursor solution were 23% and 0.05%, respectively.

[0320] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3.5. During the mixing process, the polymerization precursor solution is kept at 500 r min. -1 The mixture was stirred at a high speed and continued to be stirred for 3 hours after mixing to prepare a polymer precursor electrolyte;

[0321] 4. The electrode preparation and battery assembly test methods are the same as those in Comparative Example 6;

[0322] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify.

[0323] Comparative Example 8

[0324] 1. The electrolyte solvent dimethyl carbonate (DMC) and ethylene carbonate (EC) are mixed in a mass ratio of 4:3 to prepare a mixed solvent, and the lithium salt NaFSI and the initiator NaPF6 are dissolved in the above mixed solvent and fully dissolved to prepare a basic electrolyte containing the initiator, wherein the total mass proportion of the mixed solvent, NaFSI and initiator NaPF6 in the electrolyte is 69%, 30% and 1%;

[0325] 2. Add the initiator-containing basic electrolyte described in step 1 to perfluoro-1,3-dioxolane in a 1:2 mass ratio. During the mixing process, the polymerization precursor solution is kept at 1200 r min. -1 The mixture was stirred at a high speed and stirred for 1 hour after mixing to prepare a polymer precursor electrolyte;

[0326] 3. The electrode preparation and battery assembly methods are the same as those in Comparative Example 6;

[0327] 4. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 24 hours to solidify.

[0328] Comparative Example 9

[0329] 1. Dissolve the initiator azobisisobutyronitrile in perfluoro-1,3-dioxolane to prepare a polymerization precursor solution 1, where the mass fraction of the initiator in the polymerization precursor solution 1 is 0.2%;

[0330] 2. A non-aqueous organic solvent, ethylene carbonate (EC), and a monomer, ethylene glycol dimethacrylate, were mixed in a mass ratio of 5:2 to prepare a mixed solvent. NaFSI and an initiator, NaBF4, were added to the mixed solvent to prepare a second polymerization precursor solution. The mass fractions of NaFSI and the initiator, NaBF4, in the second polymerization precursor solution were 23% and 0.05%, respectively.

[0331] 3. Add the polymerization precursor solution 2 to the polymerization precursor solution 1 gradually. The mass ratio of polymerization precursor solution 1 to polymerization precursor solution 2 is 1:3.5. During the mixing process, the polymerization precursor solution is kept at 600 r min. -1 The mixture was stirred at a high speed and stirred for 2.5 hours after mixing to prepare a polymer precursor electrolyte;

[0332] 4. The electrode preparation and battery assembly methods are the same as those in Comparative Example 6;

[0333] 5. Inject the polymer precursor electrolyte into each battery and let it stand at room temperature for 20 hours to solidify.

[0334] Comparative Example 10

[0335] 1. The electrolyte solvents dimethyl carbonate (DMC) and ethylene carbonate (EC) were mixed in a mass ratio of 4:3 to prepare a mixed solvent, and the lithium salt NaFSI was dissolved in the mixed solvent until fully dissolved to prepare a comparative electrolyte 10, wherein the total mass fractions of the mixed solvent and NaFSI in the electrolyte were 87% and 13% respectively;

[0336] 2. Battery preparation method is the same as that of Comparative Example 6

[0337] 3. Assemble a half-cell by using the positive electrode||diaphragm||sodium metal negative electrode for charge and discharge testing;

[0338] 4. Inject the comparative electrolyte 10 into the battery and let it stand at room temperature for 12 hours before testing.

[0339] Comparative Example 11

[0340] 1. The electrolyte solvent dimethyl carbonate (DMC) and ethylene carbonate (EC) are mixed in a mass ratio of 4:3 to prepare a mixed solvent, and LiTFSI and initiator LiPF6 are dissolved in the above mixed solvent and fully dissolved to prepare a basic electrolyte containing the initiator, wherein the total mass proportions of the mixed solvent, LiTFSI and initiator LiPF6 in the basic electrolyte are 69%, 30% and 1% respectively;

[0341] 2. Add the initiator-containing basic electrolyte described in step 1 to perfluoro-1,3-dioxolane in a 1:2 mass ratio. During the mixing process, the polymerization precursor solution is kept at 600 r min. -1 The mixture was stirred at a high speed and stirred for 1 hour after mixing to prepare a polymer precursor electrolyte;

[0342] 3. The battery preparation and testing methods are the same as in Example 20.

[0343] Comparative Example 12

[0344] 1. The electrolyte solvents dimethyl carbonate (DMC) and ethylene carbonate (EC) were mixed in a mass ratio of 4:3 to prepare a mixed solvent, and the lithium salt LiTFSI was dissolved in the above mixed solvent until fully dissolved to prepare a comparative electrolyte 4, wherein the total mass fractions of the mixed solvent and LiTFSI in the electrolyte were 87% and 13% respectively;

[0345] 2. The battery preparation and testing methods are the same as in Example 20.

[0346] The batteries prepared in Examples 1 to 19 and Comparative Examples 1 to 10 were subjected to room temperature cycle performance tests. The test conditions are as follows:

[0347] The prepared battery was charged at a constant current and constant voltage of 0.5C in a constant temperature room at an ambient temperature of 25°C to the upper limit of the rated voltage, with a cut-off current of 0.02C. It was then discharged at a constant current of 0.5C until the voltage reached the lower limit of the rated voltage. The cycle was repeated 200 times, and the capacity retention rate was recorded. The capacity retention rate at the nth cycle (%) = (discharge capacity at the nth cycle / discharge capacity at the first cycle) * 100%.

[0348] The upper and lower limits of the rated voltage of LFP batteries are: 2.5-4.2V;

[0349] The upper and lower limits of the rated voltage of the NCM622 battery are: 3-4.4V;

[0350] The upper and lower limits of the rated voltage of the NCM811 battery are: 3-4.2V;

[0351] The upper and lower limits of the rated voltage of LCO batteries are: 3-4.45V;

[0352] The rated voltage upper and lower limits of Na3V2(PO4)3 battery are: 2.5-4V;

[0353] The rated voltage upper and lower limits of Na3V2(PO4)2F3 battery are: 2.5-4.3V;

[0354] The rated voltage upper and lower limits of Na2Fe(SO4)2 battery are: 2-4.3V;

[0355] The batteries prepared in Examples 20-21 and Comparative Examples 11-12 were fully charged after capacity separation and subjected to extrusion and hot box safety tests. The test requirements were based on GB 38031-2020 Safety Test Requirements for Power Batteries for Electric Vehicles, and the upper limit of the hot box test temperature was 150°C.

[0356] The test results of Examples 1 to 11 and Comparative Examples 1 to 4 are shown in Table 1 below:

[0357] Table 1

[0358] Comparative Example 5 is a pure liquid electrolyte. Because the ionic conductivity test method using a solid electrolyte has a large error with the test results using the existing test method, a vertical comparison of its ionic conductivity was not performed. After testing, the capacity retention rate of the assembled NCM811||Li half-cell at 25°C and 200 cycles was 77.8%.

[0359] The test results of Examples 12 to 19 and Comparative Examples 6 to 9 are shown in Table 2 below:

[0360] Table 2

[0361] Comparative Example 10 is a pure liquid electrolyte. Because the ionic conductivity test method using solid electrolytes has a large error with the test results using the existing test method, its ionic conductivity was not compared vertically. After testing, the assembled Na3V2(PO4)3||Na half-cell had a capacity retention rate of 75.8% after 200 cycles at 25°C.

[0362] The soft package safety test results of Examples 20-21 and Comparative Examples 11-12 are shown in Table 3:

[0363] Table 3

[0364] From the cycle test results of Examples 1 to 19, Comparative Examples 1 to 4, Comparative Examples 6 to 9, and Comparative Examples 5 and 10, it can be seen that in the absence of additives, the battery cycle retention rate using in-situ solid electrolytes is higher. Furthermore, the solid electrolytes prepared using Examples 1 to 10 all exhibit higher oxidation potentials, higher ionic conductivity, and cycle retention rates than Comparative Examples 1 to 2, indicating that the copolymerization of fluoro-1,3-dioxolane heterocyclic compounds with functional functional groups and free radical polymerization monomers can improve the uniformity of electrolyte polymerization, thereby effectively improving the stability of the electrolyte and the cycle stability of the battery. The test results of Examples 12 to 19 and Comparative Examples 6 to 9 are similar. Compared with Comparative Examples 3 to 4 and 8 to 9, Examples 1 to 19 use functional functional groups to replace part of the F in perfluoro-1,3 dioxolane, and have higher ionic conductivity, indicating that by appropriately replacing the F in perfluoro-1,3 dioxolane, ion transport is facilitated, while also retaining the effect of the F group on improving the oxidation resistance of the electrolyte. Furthermore, substitution with specialized groups, such as cyano and trimethylsiloxane, can further enhance battery cycling stability and safety. The cyano group's complexing effect on transition metal ions protects the cathode interface containing transition metals, further improving battery stability. Trimethylsiloxane's excellent stability and migration barrier properties further enhance the flame retardant properties of the electrolyte, improving battery safety. While perfluoro-1,3-dioxolane also exhibits significant flame retardancy due to its high content of fluorine, the flame retardant process generates a significant amount of hazardous hydrogen fluoride (HF) gas, which is highly toxic and difficult to recycle. Silicon-based compounds, however, achieve flame retardancy by migrating to the material surface during combustion and combusting with organic matter to form a homogeneous, insulating carbonized (Si-C) layer. This layer isolates unburned organic matter from external oxygen, inhibiting further combustion and offering a safer flame retardant mechanism than halogen gas. Therefore, substitution with trimethylsiloxane not only maintains a strong flame retardant effect but also reduces the risk of contamination. At the same time, the flame retardant effect of fluorine is also relatively weak. Safety tests were carried out by assembling soft-pack batteries, and the results showed that the electrolytes using fluorinated 1,3-dioxolane heterocyclic compounds VI and VII with functional functional groups and free radical copolymerization have better safety than perfluoro-1,3-dioxolane electrolytes, 1,3-dioxolane electrolytes and pure liquid electrolytes. The safety test results of Examples 20 to 21 and Comparative Examples 11 to 12 verified that the use of fluorinated 1,3-dioxolane heterocyclic compounds with special functional groups can further improve the thermal stability of the electrolyte and enhance the safety performance of the battery. In addition, due to the unbalanced electron cloud density at both ends of the olefinic bond of the asymmetric vinyl compound, it is not conducive to the ring formation of fluorinated 1,3-dioxolane heterocyclic compounds during the reaction process, so the vinyl compounds used in the present disclosure are all symmetrical structures.

[0365] The present disclosure provides an in-situ solid-state electrolyte obtained by solidifying a mixture comprising a fluoro-1,3-dioxolane heterocyclic compound, a free radical polymerization monomer, a first initiator, a second initiator, an electrolyte salt, and a non-aqueous organic solvent. The fluoro-1,3-dioxolane heterocyclic compound is selected from any one of Formulas I to X. In the present disclosure, a polymerization precursor solution 1 comprising a first initiator and a fluoro-1,3-dioxolane heterocyclic compound and a polymerization precursor solution 2 comprising an electrolyte salt, a second initiator, and a free radical polymerization monomer are first prepared. After mixing the polymerization precursor solutions 1 and 2, the second initiator initiates polymerization of the fluoro-1,3-dioxolane heterocyclic compound. The heat released during this process promotes polymerization of the free radical polymerization monomer initiated by the first initiator. Because the free radical polymerization reaction chain grows quickly and tends to form long chains, forming a free radical polymer network, the polymerization reaction chain of the fluoro-1,3-dioxolane heterocyclic compound grows slowly and tends to form short chains. Therefore, the short chain of the polyfluoro-1,3-dioxolane heterocyclic compound with strong cross-linking chain dynamic ability of the free radical polymer network is conducive to achieving high ionic conductivity. In the preparation method of the above-mentioned in-situ solid-state electrolyte provided by the present disclosure, the polymerization of free radical comonomers is initiated by the exothermic polymerization of the ionic polymerization of the fluoro-1,3-dioxolane heterocyclic compound at room temperature, which can avoid the uneven polymerization caused by external heating. At the same time, the polymerization of the free radical comonomer can consume the heat released by the ionic polymerization, the curing process is milder, and no bubbles remain, so that the generated in-situ solid-state electrolyte is more uniformly polymerized and has better contact with the electrode. In addition, the fluoro-1,3-dioxolane heterocyclic compound can also be grafted with various functional groups to improve the physical and chemical properties of the solid electrolyte.

[0366] The present disclosure also provides a method for preparing a fluoro-1,3-dioxolane heterocyclic compound. In the present disclosure, a vinyl compound solution and CO2F2 are subjected to an addition reaction at -50 to -25°C in the presence of a foamed metal in a protective atmosphere, the solvent is removed, and the fluoro-1,3-dioxolane heterocyclic compound is obtained after purification. Compared with the prior art, the present disclosure does not need to react at ultra-low temperatures such as -80°C, the reaction conditions are milder, and the yield of the obtained fluoro-1,3-dioxolane heterocyclic compound is high, at more than 90%. The fluorine group of the present disclosure has good chemical stability, making the solid electrolyte more stable. The fluoro-1,3-dioxolane heterocyclic compound can also be grafted with functional groups to improve the physicochemical properties of the solid electrolyte, and enhance the safety performance, electrochemical stability and energy density of the solid electrolyte.

[0367] The in-situ solid electrolyte prepared by the above preparation method has a wide electrochemical window, an oxidation voltage of >4.5V, and is suitable for high-voltage lithium batteries and high-voltage sodium batteries. The ionic conductivity is >5×10 -4When it is used in secondary batteries, taking lithium-ion half-cells as an example, it is found that the cycle capacity retention rate (100 cycles) of lithium-ion half-cells is above 90%. Industrial Applicability

[0368] The present disclosure provides a method for preparing a fluorinated 1,3-dioxolane heterocyclic compound, an in-situ solid-state electrolyte, and its preparation method and application. The fluorinated 1,3-dioxolane heterocyclic compound prepared by the method for preparing the fluorinated 1,3-dioxolane heterocyclic compound disclosed herein is added to a solid-state electrolyte, thereby improving the safety, electrochemical stability, and energy density of the solid-state electrolyte. The in-situ solid-state electrolyte disclosed herein has high ionic conductivity and a wide electrochemical window, making it suitable for high-voltage systems.

Claims

1. An in-situ solid-state electrolyte, characterized in that: Obtained by polymerization of the mixture; The mixture includes a fluoro-1,3-dioxolane heterocyclic compound, a free radical polymerization monomer, a first initiator, a second initiator, an electrolyte salt and a non-aqueous organic solvent; The fluoro-1,3-dioxolane heterocyclic compound is selected from any one of the following formulas I to X:

2. The in-situ solid-state electrolyte according to claim 1, characterized in that: The free radical polymerization monomer is selected from any one or more of vinyl ethylene carbonate, methyl vinyl sulfone, ethyl vinyl sulfone, triethylene glycol divinyl ether, methyl methacrylate, vinyl acetate, 1,3-propenyl-sultone, acrylamide, ethyl methacrylate, n-butyl methacrylate, vinyl carbonate, maleic anhydride, succinonitrile, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, vinyl acetate, polyethylene glycol diacrylate or n-butyl acrylate; The first initiator is selected from an azo initiator or a peroxide initiator; The second initiator is selected from any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorooxalatoborate, sodium hexafluorophosphate, sodium tetrafluoroborate, sodium difluorooxalatoborate, boron trifluoride, niobium pentachloride, titanium tetrachloride, aluminum chloride, ferric chloride or aluminum trifluoromethanesulfonate; The electrolyte salt includes a lithium salt and a sodium salt; The lithium salt is selected from any one or more of LiPF6, LiClO4, LiBF4, LiPOF2, LiTFSI, LiFSI, LiODFB or LiBOB; The sodium salt is selected from any one or more of NaPF6, NaClO4, NaBF4, NaTFSI, NaFSI or NaODFB; The non-aqueous organic solvent is selected from any one or more of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate or ethylene glycol dimethyl ether.

3. A method for preparing an in-situ solid-state electrolyte according to claim 1 or 2, characterized in that: The following steps are involved: S1: mixing a first initiator with a fluorinated 1,3-dioxolane heterocyclic compound represented by any one of formulas Ⅰ to Ⅹ to obtain a polymerization precursor solution 1; mixing an electrolyte salt, a second initiator, a free radical polymerization monomer and a non-aqueous organic solvent to obtain a polymerization precursor solution 2; S2: After mixing the polymerization precursor solution 1 and the polymerization precursor solution 2, a polymerization precursor electrolyte is obtained, which is injected into a battery containing a positive electrode active material for solidification to obtain an in-situ solidified electrolyte.

4. The method for preparing an in-situ solid-state electrolyte according to claim 3, characterized in that: The mass ratio of the non-aqueous organic solvent to the free radical polymerization monomer in step S1 is 5:(1-10); The mass fraction of the first initiator in the polymerization precursor solution 1 is 0.01% to 5%; The mass fraction of the second initiator in the second polymerization precursor solution is 0.01% to 3%; The mass fraction of the electrolyte salt in the second polymerization precursor solution is 12% to 30%.

5. The method for preparing an in-situ solid-state electrolyte according to claim 3, characterized in that: The mass ratio of the polymerization precursor solution 1 to the polymerization precursor solution 2 in step S2 is 1:(1-5); The polymerization is room temperature polymerization, and the polymerization time is 12 to 72 hours.

6. Use of the in-situ solid-state electrolyte according to claim 1 or 2 or the in-situ solid-state electrolyte prepared by the preparation method of the in-situ solid-state electrolyte according to any one of claims 3 to 5, characterized in that: Applicable to a solid-state secondary battery, the solid-state secondary battery comprising a positive electrode, a negative electrode, a separator and an electrolyte; The electrolyte is the in-situ solid-state electrolyte according to claim 1 or 2, or an in-situ solid-state electrolyte prepared by the method for preparing an in-situ solid-state electrolyte according to any one of claims 3 to 5.

7. The use according to claim 6, characterized in that: The solid-state secondary battery is a solid-state lithium-ion battery or a solid-state sodium-ion battery.

8. A method for preparing a fluoro-1,3-dioxolane heterocyclic compound, characterized in that: The following steps are involved: In a protective atmosphere, a vinyl compound solution and CO2F2 are mixed at -50 to -25°C, an addition reaction occurs under the catalytic action of foamed metal, and the solvent is removed and purified to obtain a fluorinated 1,3-dioxolane heterocyclic compound.

9. The preparation method according to claim 8, characterized in that: The protective atmosphere is argon; The foam metal is selected from any one or more of foam iron, foam nickel or foam copper.

10. The preparation method according to claim 8, characterized in that: The molar ratio of the vinyl compound to CO2F2 in the vinyl compound solution is 1:(1-5).

11. The method for preparing the fluoro-1,3-dioxolane heterocyclic compound according to claim 8, characterized in that: The temperature of the addition reaction is -50 to -25°C, and the time of the addition reaction is 6 to 48 hours.

12. The method for preparing the fluoro-1,3-dioxolane heterocyclic compound according to claim 8, characterized in that: The vinyl compound solution is obtained by mixing the vinyl compound and the solvent at -50 to -25°C in a protective atmosphere and heating to room temperature; The solvent in the vinyl compound solution is selected from any one or more of acetonitrile, dichloromethane, chloroform, dichloroethane, propanol, acetone, dioxane, tetrahydrofuran, methyl ethyl ketone, n-butanol, ethyl acetate, ether or chloroform.

13. The method for preparing the fluoro-1,3-dioxolane heterocyclic compound according to claim 8, characterized in that: The vinyl compound in the vinyl compound solution is selected from any one of the following formulas A to J:

14. The method for preparing the fluoro-1,3-dioxolane heterocyclic compound according to claim 12, characterized in that: The molar ratio of the vinyl compound to the solvent is 1:(2-10); The heating rate is 0.1-5°C / min.

15. The method for preparing the fluoro-1,3-dioxolane heterocyclic compound according to claim 8, characterized in that: After the addition reaction is completed, the mixture is heated to room temperature under a protective atmosphere, and then the solvent is removed to obtain the fluoro-1,3-dioxolane heterocyclic compound.

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