Cross-linking agent based on multi-site alkenyl silyl ether, preparation method of cross-linking agent, non-aqueous in-situ solid electrolyte, preparation method of non-aqueous in-situ solid electrolyte and secondary battery

Abstract

The invention relates to the field of energy, in particular to a cross-linking agent based on multi-site alkenyl silyl ether, a preparation method of the cross-linking agent, a non-aqueous in-situ solid electrolyte, a preparation method of the non-aqueous in-situ solid electrolyte and a secondary battery. The cross-linking agent based on the multi-site alkenyl silyl ether provided by the invention has a structure as shown in a formula (1), the cross-linking agent can be copolymerized with a simple organic acrylate monomer under thermal initiation to obtain a gel solid electrolyte with a high polymerization degree, and in addition, a three-dimensional network structure is successfully established by combining multiple sites and single sites, so that the cross-linking agent has a good application prospect. Not only is solvent molecules well coated, but also a channel is constructed for migration of lithium ions; and silicon-oxygen bonds are introduced on the basis, so that dissolution and precipitation of lithium ions are further improved, and the ionic conductivity of the lithium ions and the transference number of the lithium ions are improved.

Description

Technical Field

[0001] The present invention relates to the field of energy, and in particular to a crosslinker based on multi-site alkenyl silyl ether and a preparation method thereof, a non-aqueous in-situ solid electrolyte and a preparation method thereof, and a secondary battery. Background Art

[0002] With the widespread use of electric vehicles and large-scale energy storage applications, new energy batteries have developed rapidly. However, battery safety issues have attracted widespread attention and concern, which has seriously restricted the promotion and development of new energy batteries.

[0003] Currently, commercial electrolytes are primarily traditional liquid electrolytes, which primarily use small-molecule organic compounds (such as carbonates, carboxylates, and ethers) as solvents. These small-molecule organic compounds are flammable, and due to their volatility and low viscosity, they are prone to leakage and gas expansion in batteries. This can ultimately lead to combustion and create safety risks. Scientists have therefore proposed using solid-state electrolytes as a replacement. However, solid-state electrolytes such as oxides and sulfides have poor interfacial contact, resulting in large interfacial impedance, which severely hinders the migration of lithium ions. Consequently, gel polymer solid-state electrolytes have come into the spotlight. Gel polymer solid-state electrolytes are primarily composed of a polymer, a lithium salt, and a liquid solvent. After polymerization, the polymer monomers encapsulate the lithium salt and liquid solvent. Therefore, polymer solid-state electrolytes are a hybrid electrolyte system consisting of a liquid and solid phase. They combine the low interfacial impedance and high ionic conductivity of a liquid with the stability and high safety of a solid electrolyte.

[0004] Among them, polymers, as an important component of polymer solid electrolytes, not only need to provide a stable polymer structure for the electrolyte to achieve good mechanical properties of the electrolyte, but also need to provide a good channel environment for the movement of lithium ions to achieve the dissociation of lithium salts. In addition, stable electrochemical stability and excellent thermal stability are also characteristics that polymers need to have.

[0005] Currently, commonly used polymer substrates are mainly composed of PEO, PVDF / PVDF-HFP, PMMA, PAN, etc. Among them, PEO-based electrolytes have a high dielectric constant due to their large number of ether oxygen functional groups, which have good lithium ion dissolution and separation capabilities, thereby having good lithium ion conductivity. Moreover, due to the low price of PEO, it is the most commonly used polymer electrolyte. However, the contact between PEO and solvent molecules is not good, which causes a large number of solvent molecules to remain after polymerization. PVDF / PVDF-HFP-based electrolyte materials have strong electronic ability -CF- groups, which have good thermal stability and high oxidation resistance. However, PVDF polymers usually have a very high degree of crystallinity, which seriously hinders the migration of lithium ions. As a nitrile, the -CN functional group of PAN gives the polymer good oxidation resistance, and studies have found that polyacrylonitrile also has good flame retardant properties. However, PAN has a poor complexing ability with lithium ions, which makes the solubility of lithium ions poor, which is not conducive to the dissolution of lithium ions at the interface. Among them, acrylic esters similar to PMMA have a large number of highly polar carbonyl groups that can be well infiltrated with commonly used solvent molecules. After polymerization, they can form a good coating effect on the solvent, so that a small amount of monomer can be used, thereby containing more liquid in the gel polymer, and achieving higher ionic conductivity; however, the polymerization rate of acrylic ester monomers is slow and the polymerization is uneven, which greatly affects the mechanical properties of the polymer gel. In addition, small molecules with insufficient polymerization degree can easily decompose under high voltage, thereby affecting battery performance.

[0006] In summary, the poor thermal safety performance of currently commercial liquid electrolytes has always attracted people's attention. The ionic conductivity of solid electrolytes does not meet the requirements of battery applications, which has hindered the development of new energy batteries. Polymer solid-state batteries, as semi-solid batteries, are somewhere in between, with good safety performance and good battery performance. However, as an important component of the electrolyte, the choice of polymer is particularly important. The current uneven polymerization of acrylic ester monomers means that the performance of their gel state cannot be compared with liquid electrolytes, making it difficult to be effectively applied. Summary of the Invention

[0007] In light of this, the present invention provides a multi-site alkenyl silyl ether-based crosslinker and its preparation method, a non-aqueous in-situ solid electrolyte and its preparation method, and a secondary battery. The crosslinker provided by the present invention can improve the battery performance of the in-situ solid electrolyte, enabling it to achieve both excellent battery performance and thermal safety.

[0008] The present invention provides a crosslinking agent based on a multi-site alkenyl silyl ether having a structure shown in formula (1):

[0009]

[0010] in,

[0011] Selected from the structures represented by the following formula (P-1) and formula (P-2):

[0012]

[0013] Among them, * represents a connection.

[0014] The present invention also provides a method for preparing the crosslinking agent based on multi-site alkenyl silyl ether described in the above technical solution, comprising the following steps:

[0015] S1, terminal oxygen compounds react with allyl bromide to form diol compounds;

[0016] S2, the diol compound reacts with trimethylchlorosilane to form a multi-site alkenylsilyl ether-based crosslinking agent represented by formula (1);

[0017] in,

[0018] The terminal oxygen compound is glutaraldehyde and / or 1,4-cyclohexanedione;

[0019] The diol compound has a structure shown in formula (A):

[0020]

[0021] In formula (A),

[0022] Selected from the structures represented by the following formula (P-1) and formula (P-2):

[0023]

[0024] Among them, * represents a connection.

[0025] Preferably, in step S1:

[0026] The reaction temperature is 20-40°C;

[0027] The reaction is carried out under the action of a catalyst;

[0028] The catalyst is tin;

[0029] The reaction is carried out in an organic solvent;

[0030] In step S2:

[0031] The reaction temperature is 0-10°C;

[0032] The reaction is carried out in a protective atmosphere;

[0033] The reaction is carried out in the presence of triethylamine;

[0034] The reaction is preferably carried out in an organic solvent.

[0035] Preferably, step S1 comprises: adding a catalyst and an organic solvent into a container, and then dropwise adding a mixture of allyl bromide and an oxygen-terminated compound under stirring to react to form a diol compound;

[0036] Step S2 comprises: introducing a protective gas into the container to form a protective atmosphere, adding the diol compound obtained in step S1, triethylamine and an organic solvent, and then dropwise adding trimethylchlorosilane to react to form a multi-site alkenylsilyl ether-based crosslinker represented by formula (1).

[0037] The present invention also provides a non-aqueous in-situ solid electrolyte, the raw materials of which include, by mass percentage:

[0038] Lithium salt 8% to 25%;

[0039] Organic solvent 60% to 85%;

[0040] Monomer and initiator 3% to 15%;

[0041] in,

[0042] The initiator includes a cross-linking agent based on multi-site alkenylsilyl ether represented by formula (1) described in the above technical solution.

[0043] Preferably, the lithium salt is at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate), lithium difluorophosphate, lithium difluorooxalatoborate and lithium difluorobis(oxalatophosphate).

[0044] Preferably, the monomer is an acrylic ester monomer.

[0045] The present invention also provides a method for preparing the non-aqueous in-situ solid electrolyte described in the above technical solution, comprising:

[0046] A lithium salt, an organic solvent, a monomer and an initiator are mixed to obtain a solution; then, the solution is allowed to stand to obtain an in-situ solid electrolyte.

[0047] The present invention also provides a secondary battery, wherein the electrolyte is the non-aqueous in-situ solid electrolyte described in the above technical solution or is prepared by the preparation method described in the above technical solution.

[0048] Preferably, the secondary battery is a lithium-ion battery.

[0049] The cross-linking agent provided by the present invention is a new type of multi-site cross-linking agent containing a siloxy group. It can be copolymerized with a simple organic acrylate monomer under thermal initiation to obtain a gel solid electrolyte with a high degree of polymerization. In addition, the combination of multiple sites and single sites successfully builds a three-dimensional network structure, which not only achieves good coating of solvent molecules, but also constructs channels for the migration of lithium ions. On this basis, the introduction of silicon-oxygen bonds further improves the dissolution and precipitation of lithium ions, thereby improving the ionic conductivity and lithium ion migration number of lithium ions. Therefore, the in-situ solid electrolyte of the present invention has a wide electrochemical window, high lithium ion conductivity and lithium ion migration number.

[0050] The test results show that the gel solid electrolyte of the present invention has high ionic conductivity (reaching 0.45ms / cm or more) in the buckle test, and the introduction of silicon-oxygen bonds improves the ability of lithium ions to dissolve and precipitate, showing a high lithium ion migration number (reaching 0.5 or more) in the test. The degree of polymerization of the polymer is improved by cross-linking, and the content of small molecules in the polymer is reduced, and it has a wide electrochemical window (reaching 4.8V or more). The cycle test in the prepared soft-pack battery has a room temperature cycle performance that is not lower than that of the liquid electrolyte (the capacity retention rate after 300 cycles is above 75%). The thermal runaway test shows that the thermal runaway temperature is increased to above 160°C, which greatly improves the thermal safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0052] Figure 1 is the H NMR spectrum of the cross-linking agent obtained in Preparation Example 1;

[0053] Figure 2 is the H NMR spectrum of the cross-linking agent obtained in Preparation Example 2;

[0054] Figure 3 The LSV curves of the electrolytes obtained in Example 1 and Comparative Examples 1-2 are shown;

[0055] Figure 4 The electrochemical impedance curves of the electrolytes obtained in Example 1 and Comparative Examples 1-2 are shown;

[0056] Figure 5 Graph showing the cycle life of the electrolytes obtained in Example 1 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0058] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0059] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0060] As used herein, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0061] In this article, when referring to the units of a data range, if the unit is followed only by the right endpoint, it means that the units of the left and right endpoints are the same.

[0062] In a first aspect, the present invention provides a crosslinking agent based on a multi-site alkenyl silyl ether having a structure shown in formula (1):

[0063]

[0064] in,

[0065] Selected from the structures represented by the following formula (P-1) and formula (P-2):

[0066]

[0067] Among them, * represents a connection.

[0068] when When they are respectively formula (P-1) and formula (P-2), the corresponding formula (1) is respectively formula (1-1) and formula (1-2):

[0069]

[0070] The crosslinker provided by the present invention is a novel multi-site crosslinker containing siloxy groups. It can be copolymerized with simple organic acrylate monomers under thermal initiation to produce a gel-like solid electrolyte with a high degree of polymerization. Furthermore, the multi-site and single-site crosslinking successfully create a three-dimensional network structure, which not only effectively encapsulates solvent molecules but also creates channels for lithium ion migration. Furthermore, the introduction of siloxy bonds further enhances the dissolution and precipitation of lithium ions, thereby increasing the ionic conductivity and the lithium ion transference number.

[0071] The present invention also provides a method for preparing the crosslinking agent based on multi-site alkenyl silyl ether described in the above technical solution, comprising the following steps:

[0072] S1, terminal oxygen compounds react with allyl bromide to form diol compounds;

[0073] S2, the diol compound reacts with trimethylchlorosilane to form a multi-site alkenylsilyl ether-based crosslinking agent represented by formula (1);

[0074] in,

[0075] The terminal oxygen compound is glutaraldehyde and / or 1,4-cyclohexanedione;

[0076] The diol compound has a structure shown in formula (A):

[0077]

[0078] In formula (A),

[0079] Selected from the structures represented by the following formula (P-1) and formula (P-2):

[0080]

[0081] Among them, * represents a connection.

[0082] Regarding step S1:

[0083] S1. Terminal oxygen compounds react with allyl bromide to form diol compounds.

[0084] In the present invention, the terminal oxygen compound is glutaraldehyde and / or 1,4-cyclohexanedione. The source of the terminal oxygen compound is not particularly limited, and it can be a commercial product or prepared according to a preparation method known in the art.

[0085] In the present invention, the source of the allyl bromide is not particularly limited and can be a commercial product or prepared according to a preparation method known in the art.

[0086] In the present invention, the mass ratio of the terminal oxygen compound to the allyl bromide is preferably (2.64-3.36):3.6, specifically 3:3.6 or 3.36:3.6.

[0087] In the present invention, the terminal oxygen compound reacts with allyl bromide to form a diol compound represented by formula (A). When the terminal oxygen compound is glutaraldehyde or 1,4-cyclohexanedione, the diol compound represented by formula (A) is They are respectively formula (P-1) and formula (P-2), that is, the formed formula (A) is respectively formula (A-1) and formula (A-2):

[0088]

[0089] That is, when the terminal oxygen compounds are glutaraldehyde and 1,4-cyclohexanedione, the reaction routes are as follows:

[0090]

[0091] In the present invention, the reaction temperature is preferably 20-40°C, specifically 20°C, 25°C, 30°C, 35°C, or 40°C. It can be seen that the reaction can be carried out at room temperature. The reaction time is preferably 18-24 hours, specifically 18 hours, 20 hours, 22 hours, or 24 hours.

[0092] In the present invention, the reaction is preferably carried out in the presence of a catalyst. The catalyst is preferably a tin catalyst, more preferably at least one of dibutyltin dilaurate, stannous octoate, and tin powder. In the present invention, the mass ratio of the catalyst to allyl bromide is preferably 2:(3.6-4.67), specifically 2:3.6, 2:4.0, or 2:4.67.

[0093] In the present invention, the reaction is preferably carried out in an organic solvent. The organic solvent is preferably at least one of DMF (N,N-dimethylformamide), THF (tetrahydrofuran), and CHCl3 (chloroform). In the present invention, the ratio of allyl bromide to organic solvent is preferably 3.6 g: (50-60) mL, specifically 3.6 g: 50 mL, 3.6 g: 55 mL, or 3.6 g: 60 mL.

[0094] In the present invention, step S1 preferably specifically comprises: adding a catalyst and an organic solvent to a container, and then, under stirring conditions, dropwise adding a mixture of allyl bromide and an end oxygen compound to react to form a diol compound. Wherein, the container is preferably a dry container, specifically a dry flask. The stirring rate is preferably 300 to 600 rpm, specifically 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm. The dropwise addition is preferably carried out at a temperature of 20 to 40°C, specifically 20°C, 25°C, 30°C, 35°C, 40°C. It can be seen that it can be carried out at room temperature. The dropwise addition can be achieved by a dropping funnel. The temperature and time of the reaction are consistent with those described in the above technical solution and will not be repeated here. After the reaction, a diol compound represented by formula (A) is formed in the system, and a reaction solution containing a diol compound represented by formula (A) is obtained.

[0095] In the present invention, after the reaction, a post-treatment is preferably performed. The post-treatment preferably comprises: adding a mixed solution of diethyl ether and saturated NH4Cl to the reaction solution, stirring to separate the organic phase and obtain an aqueous phase; extracting the aqueous phase with an organic extraction solvent, combining the extracted organic phases, drying, removing the organic solvent, and then separating by column chromatography to obtain the diol compound represented by formula (A). The volume ratio of diethyl ether to saturated NH4Cl in the mixed solution of diethyl ether and saturated NH4Cl is preferably 1:(10-14), specifically 1:10, 1:11, 1:12, 1:13, or 1:14. The organic extraction solvent is preferably at least one of ethyl acetate, petroleum ether, and n-hexane. The extraction can be repeated multiple times, and the organic phases are then combined. The drying is preferably performed over anhydrous magnesium sulfate. The organic solvent is preferably removed by distillation under reduced pressure. After removal of the organic solvent, a crude product is obtained, which is then purified by column chromatography to obtain a pure product. The eluent used in the column chromatography separation is preferably petroleum ether.

[0096] Regarding step S2:

[0097] S2. The diol compound reacts with trimethylchlorosilane to form a multi-site alkenylsilyl ether-based crosslinking agent represented by formula (1).

[0098] In the present invention, the source of trimethylsilyl chloride (C3H9SiCl) is not particularly limited and can be a commercial product or prepared according to a preparation method known in the art. In the present invention, the mass ratio of the diol compound to trimethylsilyl chloride is preferably (3.66-4.39):2.1, specifically 3.66:2.1, 4:2.1, 4.03:2.1, or 4.39:2.1.

[0099] In the present invention, the reaction temperature is preferably 20-40°C, specifically 20°C, 25°C, 30°C, 35°C, or 40°C. It can be seen that the reaction can be carried out at room temperature. The reaction time is preferably 18-24 hours, specifically 18 hours, 20 hours, 22 hours, or 24 hours.

[0100] In the present invention, the diol compound reacts with trimethylsilyl chloride to form a multi-site alkenylsilyl ether-based crosslinker represented by formula (1). When the diol compound is formula (A-1) or formula (A-2), the resulting formula (1) is formula (1-1) or formula (1-2), and the reaction schemes are as follows:

[0101]

[0102] In the present invention, the reaction is preferably carried out in a protective atmosphere. The present invention has no particular limitation on the type of gas providing the protective atmosphere, and any conventional inert gas in the art may be used, such as nitrogen, argon, helium, etc., preferably nitrogen.

[0103] In the present invention, the reaction is preferably carried out in the presence of a catalyst, triethylamine (Et3N). The mass ratio of triethylamine to trimethylchlorosilane is preferably (2.1-2.9):2.1, specifically 2.1:2.1, 2.2:2.1, 2.3:2.1, 2.4:2.1, 2.5:2.1, 2.6:2.1, 2.7:2.1, 2.8:2.1, or 2.9:2.1.

[0104] In the present invention, the reaction is preferably carried out in an organic solvent. The organic solvent is preferably at least one of THF (tetrahydrofuran) and CHCl3 (chloroform). In the present invention, the ratio of trimethylsilyl chloride to the organic solvent is preferably 2.1 g: (20-40) mL, specifically 2.1 g: 20 mL, 2.1 g: 30 mL, or 2.1 g: 40 mL.

[0105] In the present invention, step S2 preferably specifically comprises: introducing a protective gas into a container to form a protective atmosphere, adding the diol compound, triethylamine and organic solvent obtained in step S1, and then adding trimethylchlorosilane dropwise to react to form a cross-linking agent based on a multi-site alkenyl silyl ether as shown in formula (1). The dropwise addition is preferably carried out at a temperature of 0 to 10°C, specifically 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, or 10°C. In some embodiments of the present invention, the temperature condition is provided by an ice-water bath. After the dropwise addition is completed, the reaction temperature is adjusted to the reaction temperature for reaction. After a certain reaction time, the reaction can be quenched by adding water. After the reaction, a cross-linking agent based on a multi-site alkenyl silyl ether as shown in formula (1) is formed in the system, and a reaction solution containing the cross-linking agent as shown in formula (1) is obtained.

[0106] In the present invention, after the reaction, it is preferred to further perform post-treatment. The post-treatment preferably includes: removing solid impurities by suction filtration, then extracting with an organic extraction solvent, combining the organic phases obtained by extraction, washing, drying, removing the organic solvent, and then separating by column chromatography to obtain a cross-linking agent based on a multi-site alkenylsilyl ether as shown in formula (1). Wherein, the organic extraction solvent is preferably at least one of THF (tetrahydrofuran) and ethyl acetate. The extraction can be repeated multiple times, and then the organic phases are combined. The washing is preferably washed with saturated brine, and the washing can be repeated multiple times, thereby further removing triethylamine hydrochloride by washing. The drying is preferably dried over anhydrous magnesium sulfate. The removal of the organic solvent is preferably performed by suction filtration and rotary evaporation concentration in sequence to obtain a crude product. Then, it is purified by column chromatography separation to obtain a pure product. The eluent used for the column chromatography separation is preferably petroleum ether.

[0107] In a second aspect, the present invention provides a non-aqueous in-situ solid electrolyte, the raw materials of which include, by mass percentage:

[0108] Lithium salt 8% to 25%;

[0109] Organic solvent 60% to 85%;

[0110] Monomer and initiator 3% to 15%;

[0111] in,

[0112] The initiator includes a cross-linking agent based on multi-site alkenyl silyl ether represented by formula (1) described in the above technical solution.

[0113] The mass ratio of the initiator to the monomer is (0.1-0.3):1.

[0114] In the present invention, the lithium salt is preferably at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethylsulfonyl imide) (LiTFSI), lithium bis(fluorosulfonyl imide) (LiFSI), lithium bis(oxalatoborate) (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorooxalatoborate (LiODFB) and lithium difluorodioxalatophosphate (LiDODFP). In the present invention, the mass proportion of the lithium salt in the raw material is 8% to 25%, specifically 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, and 25%.

[0115] In the present invention, the type of the organic solvent is not particularly limited, and can be a conventional organic solvent in the art, including but not limited to linear carbonate solvents or propylene carbonate (PC); wherein the linear carbonate solvent is preferably at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC). In the present invention, the mass proportion of the organic solvent in the raw material is 60% to 85%, specifically 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, more preferably 75% to 85%.

[0116] In the present invention, the monomer is preferably an acrylate monomer. The acrylate monomer is preferably at least one of methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate. In the present invention, the initiator includes a cross-linking agent based on a multi-site alkenyl silyl ether represented by formula (1) described in the above technical solution. In the present invention, the total amount of the monomer and the initiator in the raw material accounts for 3% to 15% by mass, specifically 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and more preferably 5%. Among them, the mass proportion of the initiator in the raw material is preferably 0.1% to 0.2%, specifically 0.1%, 0.15%, and 0.2%.

[0117] The present invention also provides a method for preparing the non-aqueous in-situ solid electrolyte described in the above technical solution, comprising:

[0118] A lithium salt, an organic solvent, a monomer and an initiator are mixed to obtain a solution; then, the solution is allowed to stand to obtain an in-situ solid electrolyte.

[0119] The types and amounts of the lithium salt, organic solvent, monomer and initiator are consistent with those described in the above technical solution and will not be described in detail here.

[0120] In the present invention, the mixing method is preferably stirring. The stirring speed is preferably 600 to 1200 rpm, specifically 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, or 1200 rpm. The stirring time is preferably 1 to 4 hours, specifically 1 hour, 2 hours, 3 hours, or 4 hours. The stirring is performed to thoroughly mix the raw materials until a transparent homogeneous phase is formed, thereby obtaining a transparent homogeneous solution.

[0121] The non-aqueous in-situ solid electrolyte (i.e., gel solid electrolyte) provided by the present invention is based on a carbonate monomer and introduces a specific multi-site cross-linking agent shown in formula (1) to construct a three-dimensional network structure, thereby improving the polymerization degree of the polymer and increasing the oxidation resistance of the electrolyte. The introduction of silicon-oxygen bonds improves the complexing ability of the electrolyte with lithium ions and improves its dissolution and precipitation capabilities; a stable lithium ion migration channel is constructed, thereby increasing the ionic conductivity of lithium ions and the lithium ion migration number.

[0122] Therefore, the non-aqueous in-situ solid electrolyte (i.e., gel solid electrolyte) provided by the present invention has better thermal safety performance than liquid electrolytes. Furthermore, the non-aqueous in-situ solid electrolyte provided by the present invention has a wider electrochemical window, improved ionic conductivity, and lower electrochemical impedance compared to conventional carbonate polymer solid electrolytes due to the heterogeneous polymerization, which results in a low electrochemical window and poor mechanical properties.

[0123] In a third aspect, the present invention provides a secondary battery, wherein the electrolyte is the non-aqueous in-situ solid electrolyte described in the above technical solution.

[0124] In the present invention, the secondary battery includes lithium ion batteries (including aqueous lithium ion batteries), lithium metal batteries, lithium sulfur batteries and other secondary batteries.

[0125] In the present invention, preferably, the secondary battery is a lithium-ion battery, comprising: a positive electrode, a negative electrode, a separator and an electrolyte; wherein the electrolyte is the non-aqueous in-situ solid electrolyte described in the above technical solution.

[0126] In the present invention, the active material of the positive electrode is preferably at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide and polyanion active materials, more preferably lithium cobalt oxide.

[0127] In the present invention, the active material of the negative electrode is preferably at least one of artificial graphite, natural graphite, hard carbon, silicon-carbon composite material and silicon 2 oxide, more preferably silicon-carbon composite material.

[0128] In the present invention, the separator is preferably a polypropylene (PP) separator or a polyethylene (PE) separator.

[0129] The assembly / production process of the lithium-ion battery of the present invention is not particularly limited and can be carried out according to the conventional assembly / production process of gel polymer solid electrolytes in the art.

[0130] The lithium-ion battery of the present invention adopts the above-mentioned in-situ solid-state electrolyte, has high oxidation resistance, which is specifically manifested in a wide electrochemical window shown in the buckled LSV test, has high ion migration ability, which is specifically manifested in a buckled EIS test showing high ionic conductivity and lithium ion migration number, and has good thermal safety, which is specifically manifested in a high thermal runaway temperature. That is, the present invention improves the electrochemical performance and thermal safety performance of the lithium-ion battery.

[0131] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0132] Preparatory Example 1

[0133] Preparation of the cross-linking agent shown in formula (1-1):

[0134] The reaction route is as follows:

[0135]

[0136] The preparation process is as follows:

[0137] S1. Tin powder (2 g) and DMF (50 mL) were added to a dry flask. A mixture of allyl bromide (3.6 g) and glutaraldehyde (3 g) was added from a dropping funnel under stirring at room temperature. After the addition was complete, the mixture was reacted at room temperature for 24 hours. After the reaction was completed, a mixed solution of ether (20 mL) and saturated NH4Cl (200 mL) was added, and the organic phase was separated by stirring; the resulting aqueous layer was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous MgSO4, and the organic solvent was evaporated under reduced pressure. The residue was then separated by column chromatography using petroleum ether as an eluent to obtain a pure diol compound represented by formula (A-1).

[0138] S2, choose the there-necked flask of 50mL, keep closed environment to continue to pass into argon gas 30min, then add diol compound (3.66g), triethylamine (2.1g), tetrahydrofuran solvent (20mL) shown in step S1 gained formula (A-1) in there-necked flask, under ice-water bath, trimethylchlorosilane (2.1g) is slowly added drop-wise in there-necked flask, after dropping terminates, switch to room temperature reaction, react 24h, add water quenching reaction.Then, suction filtration removes solid impurity, adds THF extraction separatory three times, organic matter further removes triethylamine hydrochloride with saturated aqueous common salt multiple washing after merging, organic phase adds anhydrous magnesium sulfate and dewaters, suction filtration, and rotary evaporation concentrates to obtain colorless liquid.Use pure petroleum ether as eluent, column chromatography separation and purification obtains colorless transparent liquid, as shown in formula (I-1).

[0139] Product characterization:

[0140] The product obtained in step S2 was characterized by nuclear magnetic hydrogen spectrum, and the results were as follows: Figure 1 The product was shown to be the structure shown in formula (1-1). The purity of the product was 99% and the yield was 82%.

[0141] Preparatory Example 2

[0142] Preparation of the cross-linking agent shown in formula (1-2):

[0143] The reaction route is as follows:

[0144]

[0145] The preparation process is as follows:

[0146] S1. Add tin powder (2 g) and DMF (50 mL) to a dry flask. Add a mixture of allyl bromide (3.6 g) and 1,4-cyclohexanedione (3.36 g) from a dropping funnel while stirring at room temperature. After the addition is complete, react at room temperature for 24 hours. After the reaction is completed, add a mixed solution of ether (20 mL) and saturated NH4Cl (200 mL), stir and separate the organic phase; the resulting aqueous layer is extracted with ethyl acetate, the organic phases are combined, dried over anhydrous MgSO4, and the organic solvent is evaporated under reduced pressure. The residue is then separated by column chromatography using petroleum ether as the eluent to obtain the pure diol compound represented by formula (A-2).

[0147] S2, choose the there-necked flask of 50mL, keep closed environment to continue to pass into argon gas 30min, then add diol compound (4g), triethylamine (2.1g), tetrahydrofuran solvent (20mL) shown in step S1 gained formula (A-2) in there-necked flask, under ice-water bath, trimethylchlorosilane (2.1g) is slowly added drop-wise in there-necked flask, after dropping terminates, switch to room temperature reaction, react 24h, add water quenching reaction.Then, suction filtration removes solid impurity, adds THF extraction separatory three times, and organic matter further removes triethylamine hydrochloride with saturated aqueous common salt multiple washing after merging, and organic phase adds anhydrous magnesium sulfate and dewaters, and suction filtration, rotary evaporation concentrates to obtain faint yellow liquid.Use pure petroleum ether as eluent, column chromatography separation and purification obtains faint yellow transparent liquid, as shown in formula (I-2).

[0148] Product characterization:

[0149] The product obtained in step S2 was characterized by magnetic hydrogen spectrum, and the results were as follows: Figure 2 The product was shown to be the structure shown in formula (1-2). The purity of the product was 99% and the yield was 74%.

[0150] Example 1

[0151] Preparation of in-situ solid electrolytes:

[0152] raw material:

[0153] Lithium salt LiPF6 14%;

[0154] Ethyl methyl carbonate organic solvent 81%;

[0155] Monomer and initiator 5%;

[0156] in,

[0157] The monomer is methyl methacrylate;

[0158] The initiator is the cross-linking agent represented by formula (1-1) obtained in Preparatory Example 1; the amount of the initiator used is 0.1% of the mass of the electrolyte.

[0159] preparation:

[0160] The lithium salt LiPF6 was dissolved in ethyl methyl carbonate organic solvent, and then the initiator and monomer were added and stirred at room temperature for 4 hours to fully mix the raw materials until they were transparent and homogeneous, thereby obtaining a carbonate in-situ solid electrolyte.

[0161] Comparative Example 1

[0162] The process was carried out in the same manner as in Example 1, except that no monomer and initiator were added to obtain a carbonate-based electrolyte.

[0163] Comparative Example 2

[0164] The process was carried out in accordance with Example 1, except that the initiator was replaced by a monomer (ie, no initiator was added, and its amount was supplemented by the monomer), to obtain a carbonate-based electrolyte.

[0165] Product Testing :

[0166] (1) Electrochemical performance test

[0167] (1.1) LSV test: The test was conducted in a button cell, with a lithium sheet as the negative electrode, a steel sheet as the positive electrode, and a 25-micron PP (polypropylene) as the diaphragm. During the assembly process, the lithium sheet was first placed in the negative electrode shell, 40 microliters of electrolyte was dripped on it, the diaphragm was placed on it, and then 40 microliters of electrolyte was dripped on the diaphragm again, followed by the positive electrode steel sheet, and finally the gasket and the positive electrode shell were added, and then packaged by a button cell packaging machine. The batteries with in-situ solid electrolytes (i.e., Example 1 and Comparative Example 2) were placed in a 45°C oven for 24 hours after preparation.

[0168] The battery prepared according to the above steps was tested using an electrochemical workstation. The test method used was linear sweep voltammetry, with a test voltage range of 2-6V, a voltage sweep rate of 1mV / s, and a sampling interval of 0.1s. The results showed that the LSV curves of the electrolytes obtained in Example 1 and Comparative Examples 1-2 were as follows: Figure 3The electrochemical impedance curve is shown in Figure 4 shown.

[0169] (1.2) Ionic conductivity test: The test was conducted in a button cell, with steel sheets as positive and negative electrodes and 25 micron PP (polypropylene) as the diaphragm. During the assembly process, the steel sheet was first placed in the negative electrode shell, 40 microliters of electrolyte was dripped on it, the diaphragm was placed on it, and then 40 microliters of electrolyte was dripped on the diaphragm again, followed by the positive electrode steel sheet, and finally the gasket and the positive electrode shell were added, and then packaged by a button cell packaging machine. The batteries with in-situ solid electrolytes (i.e., Example 1 and Comparative Example 2) were placed in a 45°C oven for 24 hours after preparation.

[0170] The battery prepared according to the above steps was tested using an electrochemical workstation. The test method used was the AC impedance method, with a test frequency range of 0.1-100000 Hz, an amplitude of 0.005 V, and a sampling interval of 2 s. The electrochemical impedance curves of the electrolytes obtained in Example 1 and Comparative Examples 1-2 are shown in Figure 1. Figure 4 shown.

[0171] The formula for calculating ionic conductivity is: σ=L / S*R

[0172] Among them, L is the distance between the positive and negative electrodes, S is the area of ​​the positive and negative electrode sheets, and R is the initial impedance.

[0173] (1.3) Ion migration number test: The test was conducted in a button cell, with lithium sheets as positive and negative electrodes and 25 micron PP (polypropylene) as the separator. During the assembly process, the lithium sheet was first placed in the negative electrode shell, 40 microliters of electrolyte was dripped on it, the separator was placed on it, and then 40 microliters of electrolyte was dripped on the separator again, followed by the positive electrode lithium sheet, and finally the gasket and the positive electrode shell were added, and then packaged by a button cell packaging machine. The batteries with in-situ solid electrolyte (i.e., Example 1 and Comparative Example 2) were placed in a 45°C oven for 24 hours after preparation.

[0174] The battery prepared according to the above steps is tested using an electrochemical workstation. The test method uses the AC impedance method to test its initial interface impedance. The test frequency range is 0.1-100000Hz, the amplitude is 0.005V, and the sampling interval is 2s. After the AC impedance test is completed, the constant voltage chronoamperometry method is selected to test the change of current under constant voltage. The test voltage is 0.01V, the test time is 3000s, and the sampling interval is 0.1s. Then continue to use the AC impedance method to test its interface impedance after stabilization. The ion migration number is calculated by the following calculation formula:

[0175] Ion migration number calculation formula:

[0176] Among them, i0, i s is the current before and after steady state, R0 and Rs are the interface impedances before and after steady state, and v is the test voltage.

[0177] The test results of electrochemical properties (electrochemical window, lithium ion conductivity, lithium ion transference number) are shown in Table 1.

[0178] Table 1: Electrochemical properties of the electrolytes obtained in Example 1 and Comparative Examples 1-2

[0179] Electrochemical window (V) Lithium ion conductivity (ms / cm) Lithium ion migration number Comparative Example 1 4.7 0.8 0.30 Comparative Example 2 4.6 0.3 0.14 Example 1 5.2 0.6 0.56

[0180] Depend on Figure 3 It can be seen that compared with Comparative Example 1 (without monomer and cross-linking agent), the electrochemical window of Comparative Example 2 (only methyl methacrylate monomer is introduced without cross-linking agent) is not improved, that is, when only methyl methacrylate monomer is added without introducing cross-linking agent, the electrochemical window is not improved, which indicates that the polymer contains more small molecules, which causes it to start to decompose at low voltage. After the cross-linking agent is introduced in Example 1, the electrochemical window is increased to 5.2V, which indicates that the introduction of cross-linking agent significantly improves the degree of polymerization, so that the stability of the gel polymer is improved, and it can withstand higher voltage without oxidative decomposition. Figure 4 It can be seen that from Comparative Example 1 to Comparative Example 2, the interface impedance of the polymer solid electrolyte has increased significantly due to the change from a liquid-liquid interface to a solid-liquid interface. However, after the cross-linking agent is introduced in Example 1, the impedance has decreased to a certain extent. This may be due to the complexation between the silicon-oxygen group and the inorganic material, thereby improving the interface wettability and reducing the interface impedance. The electrochemical performance test results in Table 1 further show that the impedance is reduced after the introduction of the cross-linking agent. In addition, the introduction of the cross-linking agent forms a three-dimensional network structure, and the lithium ion channel constructed by the silicon-oxygen bond makes the migration of lithium ions more convenient and simple, thereby increasing the ionic conductivity of lithium ions and the lithium ion migration number.

[0181] (2) Cyclic performance test

[0182] Cycle life testing: This test is conducted on lithium cobalt oxide soft-pack batteries. The electrolyte is injected into the soft-pack battery and allowed to stand at room temperature for 24 hours. The battery, containing the in-situ solid electrolyte, is then placed in a 45°C oven and allowed to stand for 24 hours. Cycle life testing is performed using constant current constant voltage charge and discharge, followed by constant current constant voltage charge and discharge. The test conditions for the capacity test are room temperature, 3-4.5V, and 0.1C charge and discharge. The cycle test conditions are room temperature, 3-4.5V, and 1C charge and discharge.

[0183] The cycle life test results of the electrolytes obtained in Example 1 and Comparative Examples 1-2 are as follows: Figure 5As shown. It can be seen that the polymer solid electrolyte formed by pure methyl methacrylate (corresponding to Example 2) has a poor degree of polymerization and an unstable polymer structure, which leads to rapid capacity decay during the cycle. After the cross-linking agent is introduced (corresponding to Example 1), the good complexing ability of the silicon-oxygen bond with lithium ions improves the ability of lithium ions to dissolve and precipitate. In addition, the formed polymer has a higher degree of polymerization, forming a stable interface at the positive and negative electrode interfaces, and is less susceptible to oxidative decomposition during the cycle, effectively extending the life of the battery.

[0184] (3) Thermal runaway test

[0185] The test results are shown in Table 2:

[0186] Table 2: Electrolyte hot box test results for Example 1 and Comparative Examples 1-2

[0187] Initial voltage (V) Thermal runaway temperature (℃) Comparative Example 1 4.16 140 Comparative Example 2 4.11 160 Example 1 4.12 180

[0188] As can be seen from Table 2, the introduction of the in-situ solid electrolyte significantly increases the thermal runaway temperature from 140°C to 160°C. After the introduction of the specific siloxane-containing cross-linking agent of the present invention, the thermal runaway temperature is further increased (to 180°C). This indicates that after the introduction of the cross-linking agent, the degree of polymerization is increased, the formed three-dimensional network structure is more stable, and the coating effect on the solvent molecules is better. At high temperatures, the polymer will not decompose or the polymer chain will not move, which will not cause more side reactions and thus lead to short circuit fire.

[0189] Example 2

[0190] The process was carried out in accordance with Example 1, except that the cross-linking agent was replaced by the cross-linking agent represented by formula (1-2) obtained in Preparatory Example 2.

[0191] Various performance tests were performed according to the test methods shown above, and the results are as follows:

[0192] Electrochemical performance: The electrochemical window is 5.3V, the lithium ion conductivity is 0.55ms / cm, and the lithium ion transference number is 0.61. It can be seen that the electrochemical window is improved, the lithium ion conductivity is improved compared to when only the monomer is introduced, and the lithium ion transference number is increased.

[0193] Cycle performance: After 300 cycles, the capacity retention rate still reached 82%, which is significantly improved compared with comparative examples 1-2.

[0194] Thermal runaway: The thermal runaway temperature is 190°C, which is significantly higher than that of Comparative Example 1-2.

[0195] Example 3

[0196] The method was implemented in accordance with Example 1, except that the ratio of the cross-linking agent to the monomer was adjusted to 8%, the ratio of the salt remained at 14%, and the ratio of the solvent was 78%.

[0197] Various performance tests were performed according to the test methods shown above, and the results are as follows:

[0198] Electrochemical Performance: The electrochemical window is 4.8V, the lithium ion conductivity is 0.47ms / cm, and the lithium ion transference number is 0.52. It can be seen that the electrochemical window, lithium ion conductivity, and lithium ion transference number show a downward trend compared to Examples 1-2. This may be because when the monomer content increases, the crosslinking degree of the monomer polymerization decreases, and the presence of some small molecule prepolymers leads to a decrease in electrolyte performance. However, compared to Comparative Examples 1-2, its performance is still improved.

[0199] Cycle performance: After 300 cycles, the capacity retention rate still reached 76%, which was significantly improved compared with Comparative Example 1-2, but decreased to a certain extent compared with Example 1-2.

[0200] Thermal runaway: The thermal runaway temperature is 160°C, which is significantly higher than that of Comparative Example 1.

[0201] Example 4

[0202] The method was implemented in accordance with Example 1, except that the ratio of the cross-linking agent to the monomer was adjusted to 10%, the ratio of the salt was still 14%, and the ratio of the solvent was 76%.

[0203] Various performance tests were performed according to the test methods shown above, and the results are as follows:

[0204] Electrochemical Performance: The electrochemical window is 4.9V, the lithium ion conductivity is 0.45ms / cm, and the lithium ion transference number is 0.52. It can be seen that the electrochemical window, lithium ion conductivity, and lithium ion transference number are comparable to those of Example 3, but show a downward trend compared to Examples 1-2. This may be because as the monomer content increases, the crosslinking degree of the monomer polymerization decreases, and the presence of some small molecule prepolymers leads to a decrease in electrolyte performance. However, compared to Comparative Examples 1-2, its performance is still improved.

[0205] Cycle performance: After 300 cycles, the capacity retention rate still reached 75%, which was significantly improved compared with Comparative Example 1-2, but decreased to a certain extent compared with Example 1-2.

[0206] Thermal runaway: The thermal runaway temperature is 170°C, which is significantly higher than that of Comparative Example 1.

[0207] Example 5

[0208] The method was implemented according to Example 2, except that the ratio of the cross-linking agent to the monomer was adjusted to 8%, the ratio of the salt was still 14%, and the ratio of the solvent was 78%.

[0209] Various performance tests were performed according to the test methods shown above, and the results are as follows:

[0210] Electrochemical Performance: The electrochemical window was 5.26 V, the lithium ion conductivity was 0.56 ms / cm, and the lithium ion transference number was 0.51. It can be seen that the electrochemical window, lithium ion conductivity, and lithium ion transference number have changed to varying degrees compared to Example 2, but the changes are relatively small. However, compared to Comparative Examples 1-2, the performance is still improved.

[0211] Cycle performance: After 300 cycles, the capacity retention rate still reached 79%, which is significantly improved compared with comparative examples 1-2.

[0212] Thermal runaway: The thermal runaway temperature is 195°C, which is significantly higher than that of Comparative Example 1-2.

[0213] Example 6

[0214] The method was implemented according to Example 2, except that the ratio of the cross-linking agent to the monomer was adjusted to 8%, the ratio of the salt was still 14%, and the ratio of the solvent was 78%.

[0215] Various performance tests were performed according to the test methods shown above, and the results are as follows:

[0216] Electrochemical Performance: The electrochemical window was 5.28 V, the lithium ion conductivity was 0.55 ms / cm, and the lithium ion transference number was 0.50. It can be seen that the electrochemical window, lithium ion conductivity, and lithium ion transference number have changed to varying degrees compared to Example 2, but the changes are relatively small. However, compared to Comparative Examples 1-2, the performance is still improved.

[0217] Cycle performance: After 300 cycles, the capacity retention rate still reached 77%, which is significantly improved compared with comparative examples 1-2.

[0218] Thermal runaway: The thermal runaway temperature is 195°C, which is significantly higher than that of Comparative Example 1-2.

[0219] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A crosslinking agent based on multi-site alkenyl silyl ether, characterized in that: It has the structure shown in formula (1): in, Selected from the structures represented by the following formula (P-1) and formula (P-2): Among them, * represents a connection.

2. A method for preparing a crosslinking agent based on a multi-site alkenyl silyl ether according to claim 1, characterized in that: The following steps are involved: S1, terminal oxygen compounds react with allyl bromide to form diol compounds; S2, the diol compound reacts with trimethylchlorosilane to form a multi-site alkenylsilyl ether-based crosslinking agent represented by formula (1); in, The terminal oxygen compound is glutaraldehyde and / or 1,4-cyclohexanedione; The diol compound has a structure shown in formula (A): In formula (A), Selected from the structures represented by the following formula (P-1) and formula (P-2): Among them, * represents a connection.

3. The preparation method according to claim 2, characterized in that In step S1: The reaction temperature is 20-40°C; The reaction is carried out under the action of a catalyst; The catalyst is tin; The reaction is carried out in an organic solvent; In step S2: The reaction temperature is 0-10°C; The reaction is carried out in a protective atmosphere; The reaction is carried out in the presence of triethylamine; The reaction is preferably carried out in an organic solvent.

4. The preparation method according to any one of claims 2 to 3, characterized in that Step S1 comprises: adding a catalyst and an organic solvent into a container, and then dropwise adding a mixture of allyl bromide and an oxygen-terminated compound under stirring to react to form a diol compound; Step S2 comprises: introducing a protective gas into the container to form a protective atmosphere, adding the diol compound obtained in step S1, triethylamine and an organic solvent, and then dropwise adding trimethylchlorosilane to react to form a multi-site alkenylsilyl ether-based crosslinker represented by formula (1).

5. A non-aqueous in-situ solid electrolyte, characterized in that In terms of mass percentage, the raw materials include: Lithium salt 8% to 25%; Organic solvent 60% to 85%; Monomer and initiator 3% to 15%; in, The initiator includes a multi-site alkenylsilyl ether-based crosslinker represented by formula (1) according to claim 1.

6. The non-aqueous in-situ solid electrolyte according to claim 5, characterized in that The lithium salt is at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate), lithium difluorophosphate, lithium difluorooxalatoborate and lithium difluorobis(oxalatophosphate).

7. The non-aqueous in-situ solid electrolyte according to claim 5, characterized in that The monomer is an acrylic ester monomer.

8. A method for preparing the non-aqueous in-situ solid electrolyte according to any one of claims 5 to 7, characterized in that: include: Mixing lithium salt, organic solvent, monomer and initiator to obtain a solution; Then, the solution was allowed to stand to obtain an in-situ solid electrolyte.

9. A secondary battery, characterized in that: The electrolyte is the non-aqueous in-situ solid electrolyte according to any one of claims 5 to 7 or is prepared by the preparation method according to claim 8.

10. The secondary battery according to claim 9, wherein The secondary battery is a lithium-ion battery.

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