A method for in-situ preparation of solid-state electrolyte based on carbonate and solid-state battery

Abstract

The application provides a method for in-situ preparation of a solid-state electrolyte based on carbonates, comprising: S1 mixing a first monomer A, a second monomer B and a lithium salt C uniformly to obtain a precursor solution; S2 adding an initiator D to the precursor solution, and stirring and dissolving to obtain an electrolyte solution; and S3 assembling the electrolyte solution with a positive electrode and a negative electrode to form a lithium ion battery, and the electrolyte solution is in-situ polymerized in the battery to form a solid-state electrolyte. A low-molecular-weight ether monomer with good film-forming property is used as a flexible matrix, and a cyclic carbonate monomer or a linear carbonate monomer with high mechanical strength is introduced as a functional monomer, and the carbonate groups are grafted onto the ether-based polymer chain through in-situ polymerization. By introducing groups with different steric hindrance effects, the packing state of the polymer chain and the charge distribution in the electrolyte are effectively controlled, and the long-term cycle stability, rate performance, thermal stability and high-voltage resistance of the all-solid-state battery are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte materials, and more particularly to a method for preparing solid electrolytes in situ based on carbonates and a solid battery. Background Technology

[0002] Lithium metal batteries (LMBs) are considered a leading candidate for next-generation batteries due to their high theoretical capacity and low electrochemical potential. However, traditional liquid LMBs face challenges such as high flammability and leakage tendency, as well as uncontrolled lithium dendrite growth, which can lead to internal short circuits and pose risks of thermal runaway or explosion. Replacing liquid electrolytes with solid-state electrolytes (SSEs) can eliminate leakage and potential safety issues while maintaining overall battery performance. Solid-state electrolytes are key materials for solid-state batteries, and the development of high-performance solid-state electrolytes has become a focus of attention for both the scientific and industrial communities. Currently, solid-state electrolytes mainly include two types: inorganic ceramics and solid polymers. While ceramic electrolytes are known for their excellent ionic conductivity and high mechanical strength, their inherent rigidity poses challenges to interfacial contact and large-scale manufacturing. In contrast, solid polymer electrolytes (SPEs) have better compatibility with existing manufacturing processes and good interfacial wettability, making them a leader in the mass production of semi-solid or all-solid-state batteries.

[0003] Polyether electrolytes, with their strong electron-donating etheroxy groups and good compatibility with lithium anodes, have become the most widely studied polymer matrix. Among them, polyethylene oxide (PEO) has become the focus material in this field due to its comprehensive advantages, including high dielectric constant, strong lithium salt solubility, excellent lithium metal compatibility, good flexibility and processability, and low cost. However, PEO-based solid electrolytes face two major bottlenecks: firstly, their room temperature ionization... The low conductivity is mainly due to the tendency of the -COC- units in the long polymer chain to crystallize, which hinders the transport of lithium ions in the amorphous phase region (where ether oxygen groups achieve ion conduction by complexing with lithium ions). Secondly, its electrochemical window is relatively narrow because the oxygen atoms in the -COC- ether bond are prone to oxidative decomposition at higher voltages.

[0004] In recent years, regulating the performance of solid-state polymer electrolytes through polymer molecular structure design has become an important research direction. For example, introducing carbonate groups with specific structures into long polymer chains can effectively suppress crystallization and improve ionic conductivity. Studies have shown that screening cyclic carbonate groups with excellent steric hindrance can optimize electrolyte performance through a triple synergistic mechanism: First, reducing the crystallinity of ethylene oxide segments increases the proportion of amorphous regions that facilitate ion transport; second, their high dielectric constant helps promote lithium salt dissociation and weakens the strong coordination between lithium ions and ether oxygen bonds, thereby improving ion mobility; third, the highly polar carbonyl group can regulate the local electric field through ion-dipole interactions, preferentially inducing the decomposition of lithium salt anions to form a stable solid-state electrolyte interface film rich in LiF, effectively suppressing the continuous decomposition of polymer chains. In addition to molecular design, innovation in preparation processes is also crucial for the development of high-performance solid-state electrolytes. Compared with traditional solution casting methods, in-situ solidification technology has advantages such as simple process, environmental friendliness, and good compatibility with existing battery production lines, making it a highly promising preparation method. The core of this technology lies in the structural design of the precursor solution and its monomer bulk polymerization process inside the battery.

[0005] Therefore, research on how to design the structure of polymer molecules to regulate the performance of solid polymer electrolytes and what methods to use to introduce carbonate groups onto ether chains is of great significance. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method based on in-situ carbonate production. A method for preparing and applying solid-state electrolytes is described, using low-molecular-weight ether monomers with good film-forming properties as a flexible matrix (first monomer), while introducing cyclic or linear carbonate monomers with high mechanical strength as functional monomers (second monomer). Carbonate groups are grafted onto the ether-based polymer chains through in-situ polymerization. This "carbonate functionalization" strategy, by introducing groups with different steric hindrance effects, can effectively control the stacking state of the polymer chains and the charge distribution within the electrolyte, significantly improving the long-term cycle stability, rate performance, thermal stability, and high-voltage tolerance of all-solid-state batteries.

[0007] The first objective of this invention is to provide a method for in-situ preparation of solid electrolytes based on carbonates, the method comprising: S1 mixes the first monomer A, the second monomer B and the lithium salt C evenly to obtain a precursor solution; S2. Initiator D is added to the electrolyte salt solution and stirred until dissolved to obtain a polymerization solution. S3 assembles the solution to be polymerized with the positive and negative electrodes to form a lithium-ion battery, wherein the electrolyte solution undergoes an in-situ polymerization reaction inside the battery to form a solid electrolyte.

[0008] Specifically, in step S1, the first monomer A is one or more of ethylene oxide, propylene oxide, 1,3-dioxolane, polyethylene glycol diacrylate, and polyethylene glycol methacrylate.

[0009] Specifically, in step S1, the second monomer B is a cyclic carbonate monomer or a linear carbonate monomer; the cyclic carbonate monomer in step S1 is one or more of vinylene carbonate, ethylene ethylene carbonate, ethylene carbonate, propylene carbonate, trimethylene carbonate, and 2-ethoxycarbonyl-2-methyltrimethylene carbonate; the linear carbonate... The monomers are any one or a combination of propargyl methyl carbonate, allyl methyl carbonate, ethyl allyl carbonate, diallyl pyrocarbonate, diallyl carbonate, allyl chloroformate, allyl phenyl carbonate, allyl ethyl carbonate, allyl oxalate, allyl acetate, and isonicotinic acid allyl ester.

[0010] Specifically, the lithium salt C in step S1 is any one or a combination of lithium difluorooxalate borate, lithium dioxalate borate, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium hexafluorophosphate, and lithium bis(fluorosulfonyl)imide.

[0011] Specifically, the initiator D in step S2 is any one of benzoyl peroxide, dicumyl peroxide, hydrogen peroxide, 2,2'-azobis(isobutyronitrile), and azobisisoheptanenitrile.

[0012] Specifically, in step S1, the molar ratio of the first monomer A to the second monomer B is (0.1-10):1.

[0013] Specifically, in step S2, the concentration of the lithium salt in the polymerization solution is 0.1-10 mol / L, the mass percentage of initiator D is 0.1-1%, the mass percentage of monomer A is 60-98%, and the mass percentage of monomer B is 2-40%.

[0014] Specifically, the in-situ polymerization reaction in step S3 is carried out at a temperature of 30-90°C for 6-30 hours.

[0015] The second objective of this invention is to provide a solid-state battery comprising a solid electrolyte, a positive electrode, a negative electrode, and a battery separator prepared by the method described above.

[0016] Specifically, the positive electrode is any one of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, copper sheet, and stainless steel; the negative electrode is any one of lithium metal, silicon oxide, stainless steel, and graphite.

[0017] Compared with the prior art, the beneficial effects of the present invention include: This invention designs a solid electrolyte based on in-situ polymerization. The system uses a low-molecular-weight ether monomer with good film-forming properties as a flexible matrix (first monomer), and simultaneously introduces a cyclic carbonate monomer (such as ethylene carbonate VC or ethylene ethylene carbonate VEC) or a linear carbonate monomer with high mechanical strength as a functional monomer (second monomer). Through in-situ polymerization, carbonate groups are grafted onto the ether polymer chain. This "carbonate functionalization" strategy, by introducing VC or VEC groups with different steric hindrance effects, can effectively control the stacking state of the polymer chain and the charge distribution inside the electrolyte, thereby inhibiting ether chain crystallization, improving ionic conductivity, and broadening the electrochemical window. Secondly, the highly polar carbonyl groups (-C=O) on the cyclic carbonate side chains can shield the electrostatic interaction between lithium salt cations and anions through ion-dipole interactions, promoting lithium salt dissociation and ion transport. In particular, the carbonyl groups of VEC can preferentially induce anions (such as DFOB) in the electrolyte. - The decomposition of ) helps form a stable solid electrolyte interphase (SEI) film rich in LiF. This SEI film effectively prevents the continuous oxidative decomposition of ether chains under high voltage. Furthermore, thanks to the interaction between the carbonyl group and Li... + With relatively weak binding energy, lithium ions can migrate rapidly along the VEC side chains. The prepared solid-state electrolyte exhibits excellent overall electrochemical performance thanks to its flexible polymer chain movement and uniform charge distribution. This system not only effectively inhibits the oxidative decomposition of the ether-based component under high voltage but also significantly improves the long-term cycle stability, rate performance, thermal stability, and high-voltage tolerance of the all-solid-state battery. Furthermore, the carbonate raw material used can be industrially produced on a large scale at low cost, making this preparation method highly promising for industrialization and market application. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 (ak) are impedance spectra of steel / steel solid-state batteries prepared in Examples 1-10 and Comparative Example 1 of the present invention at different temperatures; Figure 2 This is a comparison of Arrhenius curves of steel / steel solid-state batteries prepared in Examples 1-10 and Comparative Example 1 of the present invention; Figure 3 Electrostatic potential diagrams calculated by density functional theory for the solid electrolytes prepared in Examples 1-2 and Comparative Example 1 of this invention; Figure 4(ab) are comparative graphs of differential scanning calorimetry curves and thermogravimetric curves of the solid electrolytes prepared in Examples 1-2 and Comparative Example 1 of the present invention, respectively. Figure 5 (ab) are comparison graphs of chronoamperometry curves and performance scan curves of lithium / lithium solid-state batteries prepared in Examples 1-2 and Comparative Example 1, respectively. Figure 6 (a) and (d) are respectively the cyclic voltammetry curves of the lithium / steel solid-state battery and the lithium / cobalt oxide battery prepared in Comparative Example 1 of the present invention. Figure 6 (b, e) are the cyclic voltammetry curves of the lithium / steel solid-state battery and the lithium / cobalt oxide battery prepared in Example 1 of the present invention. Figure 6 (c, f) are the cyclic voltammetry curves of the lithium / steel solid-state battery and the lithium / cobalt oxide battery prepared in Example 2 of the present invention. Figure 7 (a, d, g, j) are the charge-discharge curves of the lithium / cobalt oxide half-cell, lithium / lithium iron phosphate half-cell, lithium / ternary NCM532 half-cell and silicon oxide / lithium half-cell prepared in Comparative Example 1 of the present invention at 25°C. Figure 7 (b, e, h, k) are the charge-discharge curves of the lithium / cobalt oxide half-cell, lithium / iron phosphate half-cell, lithium / ternary NCM532 half-cell and silicon oxide / lithium half-cell prepared in Example 1 of the present invention at 25°C. Figure 7 (c, f, i, l) are the charge-discharge curves of the lithium / cobalt oxide half-cell, lithium / iron phosphate half-cell, lithium / ternary NCM532 half-cell and silicon oxide / lithium half-cell prepared in Example 2 of the present invention at 25°C. Figure 8 (ac) is a comparison of the cycle performance of the lithium / lithium iron phosphate half-cell, lithium / lithium cobalt oxide half-cell, lithium / ternary NCM532 half-cell and lithium / lithium symmetric cell prepared in Comparative Example 1 and Examples 1-2 of the present invention at 25°C. Figure 9 (ac) are SEM images of the lithium / cobalt oxide electrode sheets of the lithium / cobalt oxide half-cells prepared in Comparative Example 1 and Examples 1-2 of this invention after 150 cycles. Figure 9 (df) are SEM images of the lithium / lithium iron phosphate electrode sheets of the lithium / lithium iron phosphate half-cells prepared in Comparative Example 1 and Examples 1-2 of this invention after 200 cycles. Figure 9 (jl) are SEM images of the silicon oxide / lithium half-cells prepared in Comparative Example 1 and Examples 1-2 of this invention after 100 cycles. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the present invention.

[0021] Example 1 S1. Polyethylene glycol methacrylate (PDEM), ethylene ethylene carbonate (VEC) and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of polyethylene glycol methacrylate (PDEM) is 80.79%, and the mass percentage of ethylene ethylene carbonate (VEC) is 19.21%, wherein the molar ratio of PDEM to VEC is 1:1; S3. The 20 μL solution to be polymerized is sequentially mixed with lithium metal sheet, stainless steel sheet, lithium cobalt oxide, lithium iron phosphate, and ternary NCM532 as the positive electrode material, and lithium metal sheet, stainless steel sheet, and silicon oxide 500 as the negative electrode material, with a cellulose membrane as the separator; and with lithium metal sheet and stainless steel sheet as the positive electrode material, silicon oxide as the negative electrode material, and a cellulose membrane as the separator. The solutions are placed together in an argon glove box with a moisture and oxygen content of less than 0.01 ppm. The electrolyte solution is polymerized in situ at 60°C for 10 h inside the battery to form the solid electrolyte prepared in Example 1, denoted as PEVEC. The solutions are then assembled into the lithium / lithium solid-state battery, steel / steel solid-state battery, lithium / steel solid-state battery, lithium / lithium cobalt oxide solid-state battery, lithium / lithium iron phosphate solid-state battery, lithium / ternary NCM532 solid-state battery, and silicon oxide / lithium solid-state battery prepared in Example 1.

[0022] Example 2 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 97.96%, and the mass percentage of VC (vinyl carbonate) is 2.04%, wherein the molar ratio of PDEM to VC is 0.9:0.1; S3. The 80 μL solution to be polymerized is sequentially mixed with lithium metal sheet, stainless steel sheet, lithium cobalt oxide, lithium iron phosphate, and ternary NCM532 as the positive electrode material, lithium metal sheet and stainless steel sheet as the negative electrode material, and cellulose membrane as the separator; and with lithium metal sheet as the positive electrode material, silicon oxide as the negative electrode material, and cellulose membrane as the separator. The solutions are placed together in an argon glove box with a moisture and oxygen content of less than 0.01 ppm. The electrolyte solution is polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 2. Since the molar ratio of PDEM:VC is 0.9:0.1, it is denoted as PEVC-0.1. The lithium / lithium solid battery, lithium / steel solid battery, steel / steel solid battery, lithium / lithium cobalt oxide solid battery, lithium / lithium iron phosphate solid battery, lithium / ternary NCM532 solid battery, and silicon oxide / lithium solid battery prepared in Example 2 are also included.

[0023] Example 3 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until uniformly dissolved to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 95.76%, and the mass percentage of VC (vinyl carbonate) is 4.24%, wherein the molar ratio of PDEM to VC is 0.8:0.2; S3. The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C for 10 h inside the battery to form the solid electrolyte prepared in Example 3, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.2.

[0024] Example 4 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 92.82%, and the mass percentage of VC (vinyl carbonate) is 7.18%, wherein the molar ratio of PDEM to VC is 0.7:0.3; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 4, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.3.

[0025] Example 5 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 89.44%, and the mass percentage of VC (vinyl carbonate) is 10.56%, wherein the molar ratio of PDEM to VC is 0.6:0.4; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 5, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.4.

[0026] Example 6 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until uniformly dissolved to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 87.59%, and the mass percentage of VC (vinyl carbonate) is 12.41%, wherein the molar ratio of PDEM to VC is 0.5:0.5; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 6, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.5.

[0027] Example 7 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until uniformly dissolved to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 78.69%, and the mass percentage of VC (vinyl carbonate) is 21.31%, wherein the molar ratio of PDEM to VC is 0.4:0.6; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 7, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.6.

[0028] Example 8 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until uniformly dissolved to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 70.59%, and the mass percentage of VC (vinyl carbonate) is 20.41%, wherein the molar ratio of PDEM to VC is 0.3:0.7; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 8, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.7.

[0029] Example 9 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 58.18%, and the mass percentage of VC (vinyl carbonate) is 41.82%, wherein the molar ratio of PDEM to VC is 0.2:0.8; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 9, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.8.

[0030] Example 10 S1 is prepared by uniformly mixing polyethylene glycol methacrylate (PDEM), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB) to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of PDEM (polyethylene glycol methacrylate) is 38.4%, and the mass percentage of VC (vinyl carbonate) is 61.6%, wherein the molar ratio of PDEM to VC is 0.1:0.9; S3 The 80 μL solution to be polymerized was combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 10, and assembled into a lithium / lithium iron phosphate solid battery, denoted as PEVC-0.9.

[0031] Example 11 S1 mixes ethylene oxide (PEO), ethylene carbonate (EC), and lithium dioxalate borate (LiBOB) evenly to obtain a precursor solution; S2 is added to the precursor solution and stirred until homogeneous to obtain the polymerization solution; in the polymerization solution, the concentration of LiBOB is 1 mol / L, the mass percentage of ABVN is 0.5% (relative to the total monomer mass), the mass percentage of PEO is 45.69%, and the mass percentage of EC is 54.31%; S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 11, and assembled into a lithium / lithium iron phosphate solid battery.

[0032] Example 12 S1 is prepared by uniformly mixing propylene oxide (PO), propylene carbonate (PC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to obtain a precursor solution; S2 adds benzoyl peroxide (BPO) to the precursor solution and stirs to dissolve it evenly to obtain the polymerization solution; in the polymerization solution, the concentration of LiTFSI is 1 mol / L, the mass percentage of ABVN is 0.5% (relative to the total monomer mass), the mass percentage of PO is 55.37%, and the mass percentage of PC is 44.63%; S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 12, and assembled into a lithium / lithium iron phosphate solid battery.

[0033] Example 13 S1 mixes 1,3-dioxolane (DOL), trimethylene carbonate (TMC) and lithium tetrafluoroborate (LiBF4) evenly to obtain a precursor solution; S2 adds benzoyl peroxide (BPO) to the precursor solution and stirs to dissolve it evenly to obtain the polymerization solution; in the polymerization solution, the concentration of LiBF4 is 1.5 mol / L, the mass percentage of BPO is 0.5% (relative to the total monomer mass), the mass percentage of DOL is 63.75%, and the mass percentage of TMC is 36.25%; S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 13, and then lithium / lithium iron phosphate is assembled into a solid battery.

[0034] Example 14 S1. Polyethylene glycol diacrylate (PEGDA, Mn=200), 2-ethoxycarbonyl-2-methyltrimethylene carbonate and lithium hexafluorophosphate (LiPF6) are mixed evenly to obtain a precursor solution. S2 adds dicumyl peroxide to the precursor solution and stirs to dissolve it evenly to obtain the polymerization solution; in the polymerization solution, the concentration of LiPF6 is 1 mol / L, the mass percentage of dicumyl peroxide is 0.5% (relative to the total monomer mass), the mass percentage of polyethylene glycol diacrylate (PEGDA, Mn=200) is 87.54%, and the mass percentage of 2-ethoxycarbonyl-2-methyltrimethylene carbonate is 12.46%; S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 14, and assembled into a lithium / lithium iron phosphate solid battery.

[0035] Example 15 S1. After uniformly mixing polyethylene glycol diacrylate (PEGDA, Mn=400), diallyl pyrocarbonate (DD) and lithium bis(fluorosulfonyl)imide (LiFSI), a precursor solution is obtained. S2 adds hydrogen peroxide to the precursor solution and stirs to dissolve it evenly to obtain the polymerization solution; in the polymerization solution, the LiFSI concentration is 1 mol / L, the mass percentage of hydrogen peroxide is 0.5% (relative to the total monomer mass), the mass percentage of polyethylene glycol diacrylate (PEGDA, Mn=400) is 68.24%, and the mass percentage of DD is 31.76%; S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 15, and assembled into a lithium / lithium iron phosphate solid battery.

[0036] Example 16 S1. After uniformly mixing polyethylene glycol diacrylate (PEGDA, Mn=600), ethyl allyl carbonate and lithium bisfluorosulfonyl imide (LiFSI), a precursor solution is obtained. S2 adds hydrogen peroxide to the precursor solution and stirs to dissolve it evenly to obtain the polymerization solution; in the polymerization solution, the LiFSI concentration is 3 mol / L, the mass percentage of hydrogen peroxide is 0.5% (relative to the total monomer mass), the mass percentage of polyethylene glycol diacrylate (PEGDA, Mn=600) is 83.78%, and the mass percentage of ethyl allyl carbonate is 16.22%. S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 16, and assembled into a lithium / lithium iron phosphate solid battery.

[0037] Example 17 S1. After uniformly mixing polyethylene glycol methyl ether acrylate (PEGMA, Mn=300), allyl methyl carbonate (AMC), and lithium difluorooxalate borate (LiDFOB), a precursor solution is obtained. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until homogeneous to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of polyethylene glycol methyl ether acrylate (PEGMA, Mn=300) is 72.10%, and the mass percentage of AMC is 27.90%; S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 17, and assembled into a lithium / lithium iron phosphate solid battery.

[0038] Example 18 S1. Polyethylene glycol methyl ether acrylate (PEGMA, Mn=1200), propargyl methyl carbonate (PMC), and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 5 mol / L, the mass percentage of polyethylene glycol methyl ether acrylate (PEGMA, Mn=1200) is 89.6%, the mass percentage of PMC is 10.4%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3 The 80 μL solution to be polymerized is combined with lithium iron phosphate, lithium metal sheets and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 18, and assembled into a lithium / lithium iron phosphate solid battery.

[0039] Example 19 S1. Polyethylene glycol methyl ether acrylate (PEGMA, Mn=2000), diallyl carbonate (DC), and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until homogeneous to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), the mass percentage of polyethylene glycol methyl ether acrylate (PEGMA, Mn=2000) is 93.37%, and the mass percentage of DC is 6.63%; S3 The 80 μL solution to be polymerized is combined with lithium cobalt oxide, lithium metal sheet and cellulose membrane in an argon glove box with moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 19, and assembled into a lithium / lithium cobalt oxide solid battery.

[0040] Example 20 S1. After uniformly mixing polyethylene glycol methyl ether acrylate (PEGMA, Mn=4000), allyl chloroformate (AC) and lithium difluorooxalate borate (LiDFOB), a precursor solution is obtained. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of polyethylene glycol methyl ether acrylate (PEGMA, Mn=4000) is 97.89%, the mass percentage of VC is 2.11%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3 The 80 μL solution to be polymerized is combined with lithium manganese oxide, lithium metal sheet and cellulose membrane in an argon glove box with moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 20, and assembled into a lithium / lithium manganese oxide solid battery.

[0041] Example 21 S1. Polyethylene glycol methyl ether acrylate (PEGMA, Mn=480), allyl phenyl carbonate (APC) and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain the polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of polyethylene glycol methyl ether acrylate (PEGMA, Mn=480) is 98.21%, the mass percentage of VC is 1.79%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3 The 80 μL solution to be polymerized was combined with ternary nickel cobalt manganese oxide lithium NCM532, silicon oxide 500 and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution was polymerized in situ at a high temperature of 60°C inside the battery for 10 h to form the solid electrolyte prepared in Example 21, and assembled into a silicon oxide 500 / nickel manganese oxide solid battery.

[0042] Example 22 S1. Polyethylene glycol methyl ether acrylate (PEGMA, Mn=500), allyl ethyl carbonate (AEC) and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, and the mass percentage of polyethylene glycol methyl ether acrylate (PEGMA, Mn=500) is 63.80%, the mass percentage of AEC is 36.20%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3 The 80 μL solution to be polymerized is combined with ternary lithium nickel cobalt manganese oxide (NCM53), lithium metal sheet and cellulose membrane in an argon glove box with moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at 90°C inside the battery for 6 hours to form the solid electrolyte prepared in Example 22, and assembled into a lithium / ternary NCM532 solid battery.

[0043] Example 23 S1. Polyethylene oxide (PEO), allyl oxalate (DO), and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of PEO is 79.35%, the mass percentage of DO is 20.65%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3 The 80 μL solution to be polymerized is combined with lithium metal, silicon oxide and cellulose membrane in an argon glove box with a moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at a high temperature of 70°C inside the battery for 24 h to form the solid electrolyte prepared in Example 23, and assembled into a silicon oxide / lithium solid battery.

[0044] Example 24 S1. After mixing polyethylene oxide (PEO), allyl acetate (AA), and lithium difluorooxalate borate (LiDFOB) evenly, a precursor solution is obtained. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of PEO is 74.98%, the mass percentage of AA is 25.02%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3 The 80 μL solution to be polymerized is combined with nickel-cobalt-aluminum ternary material, lithium metal sheet and cellulose membrane in an argon glove box with moisture and oxygen content of less than 0.01 ppm to assemble a battery. The electrolyte solution is polymerized in situ at 50°C inside the battery for 25 h to form the solid electrolyte prepared in Example 24, and then assembled into a solid battery.

[0045] Example 25 S1 mixes polyethylene oxide (PEO), allyl isonicotinamide (AI), and lithium difluorooxalate borate (LiDFOB) evenly to obtain a precursor solution; S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of PEO is 64.99%, the mass percentage of AI is 35.23%, and the mass percentage of AIBN is 0.5% (relative to the total monomer mass). S3. The 80 μL solution to be polymerized is assembled with a lithium metal sheet to form a symmetrical battery. The separator is a cellulose separator. The battery is assembled in an argon glove box with a moisture and oxygen content of less than 0.01 ppm. The electrolyte solution is polymerized in situ at 30°C inside the battery for 30 h to form the solid electrolyte prepared in Example 25, and then assembled into a lithium / lithium solid battery. Comparative Example 1 S1. Polyethylene glycol methacrylate (PDEM) and lithium difluorooxalate borate (LiDFOB) are mixed evenly to obtain a precursor solution. S2 is added to the precursor solution with 2,2'-azobis(isobutyronitrile) (AIBN) and stirred until dissolved to obtain a polymerization solution; in the polymerization solution, the concentration of LiDFOB is 1 mol / L, the mass percentage of AIBN is 0.5% (relative to the total monomer mass), and the mass percentage of polyethylene glycol methacrylate is 100%; S3 sequentially reacts the 80 μL solution to be polymerized with lithium metal sheet, stainless steel sheet, lithium cobalt oxide, lithium iron phosphate, and ternary NCM532 as the positive electrode material, lithium metal sheet as the negative electrode material, and cellulose membrane as the separator; and with lithium metal sheet and stainless steel sheet as the positive electrode material, silicon oxide as the negative electrode material, and cellulose membrane as the separator. Batteries are assembled in an argon glove box with a moisture and oxygen content of less than 0.01 ppm. The electrolyte solution is polymerized in situ at 60°C inside the battery for 10 hours to form the solid electrolyte prepared in Comparative Example 1, denoted as P-PDEM. These are then assembled into lithium / lithium solid-state batteries, lithium / steel solid-state batteries, lithium / lithium cobalt oxide solid-state batteries, steel / steel solid-state batteries, lithium / lithium iron phosphate solid-state batteries, lithium / ternary NCM532 solid-state batteries, and silicon oxide / lithium solid-state batteries prepared in Comparative Example 1.

[0046] Performance testing Electrochemical performance testing: Formation of lithium / lithium cobalt oxide solid-state batteries: Three constant current charge-discharge cycles were performed using a current density of 0.1 C (1 C = 160 mAh / g), with a charging cutoff potential of 4.4 V and a discharging cutoff potential of 3 V. After completion, electrochemical performance was tested.

[0047] Formation of lithium / lithium iron phosphate solid-state batteries: 10 constant current charge-discharge cycles were performed using a current density of 0.1 C (1 C = 160 mAh / g), with a charging cutoff potential of 4.2 V and a discharging cutoff potential of 2.5 V. After completion, the electrochemical performance at 0.5 C was tested.

[0048] Formation of lithium / ternary NCM532 solid-state battery: Three constant current charge-discharge cycles were performed at a current density of 0.1 C (1 C = 160 mAh / g), with a charging cutoff potential of 4.4 V and a discharging cutoff potential of 3 V. After completion, the electrochemical performance of the battery was tested at 0.5 C.

[0049] Formation of silicon-oxygen / lithium batteries: Three constant-current charge-discharge cycles were performed at a current density of 0.1 C (1 C = 500 mAh / g). After the charging cutoff potential was 3 V and the discharging cutoff potential was 4.4 V, the cycle performance was tested at 0.5 C. Electrochemical performance tests were then performed at 0.2 C after the charging cutoff potential was 2 V and the discharging cutoff potential was 0.05 V.

[0050] Cyclic performance test: The lithium / lithium iron phosphate battery was cycled 1000 times at a 0.5 C rate, with a charge cutoff potential of 4.2 V and a discharge cutoff potential of 2.5 V. The lithium / lithium cobalt oxide battery was cycled 120 times at a 0.1 C rate, with a charge cutoff potential of 4.4 V and a discharge cutoff potential of 3 V. The lithium / ternary NCM532 battery was cycled 70 times at a 0.5 C rate, with a charge cutoff potential of 4.4 V and a discharge cutoff potential of 3 V. The silicon oxide / lithium battery was cycled 100 times at a 0.2 C rate. The lithium / lithium symmetric battery was charged and discharged at a current density of 0.1 mA cm⁻². The lithium / copper battery was charged and discharged at a current density of 0.1 mA / cm⁻². 2 Discharge at the current density for 2 hours, with a charging cutoff voltage of 2V.

[0051] Figure 1(ak) are the impedance spectra of steel / steel solid batteries prepared in Examples 1-10 and Comparative Example 1 at different temperatures, respectively. As the temperature increases, the impedance gradually decreases. As the content of vinylene carbonate (VC) increases, the impedance shows a trend of first decreasing and then increasing. The electrolyte with the optimal ratio of VC shows a lower impedance, and the electrolyte with the optimal mass percentage of VEC monomer of 19.21% shows the lowest impedance, which is conducive to the rapid transport of lithium ions. Figure 2 The image shows a comparison of Arrhenius curves for the steel / steel solid-state batteries prepared in Examples 1-10 and Comparative Example 1. Compared to Comparative Example 1, with the addition of VEC side chains, the activation energy (Ea) of Li ion diffusion in the electrolyte of Example 1 (PEVEC) decreased from 0.375 eV to 0.325 eV. Figure 2 ), indicating that Li + Migration enhancement. Figure 3 Electrostatic potential diagrams calculated using density functional theory for the solid electrolytes prepared in Examples 1-2 and Comparative Example 1 of this invention are shown; their electronegativity distributions are compared. In the VC monomer, the negative charge is mainly concentrated on the C=O and COC groups, forming a stronger local negative charge than in VEC. The electrolyte based on Example 2 exhibits a non-uniform electron cloud distribution around the C=O groups. In contrast, the electrolyte of Example 1 has a more uniform charge distribution and enhanced structural stability due to optimized steric hindrance. Li in the VEC side chain... + The decrease in coordination strength further lowers the ion migration barrier, thereby increasing ion conductivity.

[0052] Figure 4 (ab) are comparative diagrams of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) curves of the solid electrolytes prepared in Examples 1-2 and Comparative Example 1, respectively. Due to the high spin of the ether bond and the flexible linear structure of PDEM, the glass transition temperature of Comparative Example 1 is -50.31℃. After introducing different sterically hindered side chains, the glass transition temperatures of Examples 1 and 2 decreased to -57.02℃ and -56.51℃, respectively. The thermal stability of the electrolytes was investigated using thermogravimetric analysis. The first decomposition of the electrolyte in Example 1 occurred at 230℃ and ended near 310℃, corresponding to the decomposition of LiDFOB. The second stage of degradation began at approximately 310℃, related to the decomposition of Example 1. This indicates that the electrolyte prepared in Example 1 has good high-temperature resistance. Figure 5(ab) are comparison graphs of chronoamperometry curves and performance scan curves of lithium / lithium solid-state batteries prepared in Examples 1-2 and Comparative Example 1, respectively. The high migration number in Example 1 can be attributed to two factors: First, the highly polar side chain can effectively protect ion-ion interactions and increase the concentration of free carriers. Furthermore, lithium ions can migrate along adjacent VEC segments through an effective hopping mechanism. Second, the VEC side chain can interact with DFOB... - Coordination restricts the movement of anions. Due to the efficient transport of Li ions, the impedance of Example 1 was significantly reduced after the introduction of sterically hindered VEC side chains. The electrochemical stability of the electrolyte was determined using linear sweep voltammetry (LSV). Example 1 exhibited a wide electrochemical window up to 4.9 V. These results indicate that carbonyl VEC side chains with strong electron absorption can stabilize the polymer backbone and improve its antioxidant capacity. Figure 6 (a) and (d) are respectively the cyclic voltammetry curves of the lithium / steel solid-state battery and the lithium / cobalt oxide battery prepared in Comparative Example 1 of the present invention. Figure 6 (b, e) are the cyclic voltammetry curves of the lithium / steel solid-state battery and the lithium / cobalt oxide battery prepared in Example 1 of the present invention. Figure 6 (c, f) are the cyclic voltammograms of the lithium / steel solid-state battery and the lithium / cobalt oxide battery prepared in Example 2 of the present invention; it can be seen that compared with Comparative Example 1, Example 1 and Example 2 have higher cycle stability. Figure 7 (a, d, g, j) are the charge-discharge curves of the lithium / cobalt oxide half-cell, lithium / lithium iron phosphate half-cell, lithium / ternary NCM532 half-cell and silicon oxide / lithium half-cell prepared in Comparative Example 1 of the present invention at 25°C. Figure 7 (b, e, h, k) are the charge-discharge curves of the lithium / cobalt oxide half-cell, lithium / iron phosphate half-cell, lithium / ternary NCM532 half-cell and silicon oxide / lithium half-cell prepared in Example 1 of the present invention at 25°C. Figure 7 (c, f, i, l) are the charge-discharge curves of the lithium / cobalt oxide half-cell, lithium / iron phosphate half-cell, lithium / ternary NCM532 half-cell and silicon oxide / lithium half-cell prepared in Example 2 of the present invention at 25°C, respectively. It can be clearly seen that the charge-discharge curves of Examples 1 and 2 with added carbonate monomers are stable and have small capacity decay, while the capacity decay of Comparative Example 1 is large. This shows that the introduction of carbonate effectively improves the capacity decay of the battery. Figure 8(ac) is a comparison of the cycle performance at 25°C of the lithium / lithium iron phosphate half-cell, lithium / lithium cobalt oxide half-cell, lithium / ternary NCM532 half-cell, and lithium / lithium symmetric cell prepared in Comparative Example 1 and Examples 1-2 of this invention. In Comparative Example 1, although the lithium / lithium iron phosphate half-cell did not show damage after multiple cycles, its capacity continuously decreased, showing a rapid decline after 750 cycles. In contrast, in the carbonate-added electrolytes, the battery capacity of Examples 1 and 2 showed virtually no decrease after 1000 cycles. Both examples extended the cycle life of the half-cells. Figure 9 (ac) are SEM images of the lithium / cobalt oxide electrode sheets of the lithium / cobalt oxide half-cells prepared in Comparative Example 1 and Examples 1-2 of this invention after 150 cycles. Figure 9 (df) are SEM images of the lithium / lithium iron phosphate electrode sheets of the lithium / lithium iron phosphate half-cells prepared in Comparative Example 1 and Examples 1-2 of this invention after 200 cycles. Figure 9 (jl) are SEM images of the silicon oxide / lithium half-cells prepared in Comparative Example 1 and Examples 1-2 after 100 cycles. Compared with Comparative Example 1, Examples 1 and 2 both showed a flatter and more uniform surface, indicating that the carbonate regulation strategy improved the stability of the electrolyte and was beneficial to the stable deposition and stripping of lithium.

[0053] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for in-situ preparation of solid electrolytes based on carbonates, characterized in that, The method includes: S1 mixes the first monomer A, the second monomer B and the lithium salt C evenly to obtain a precursor solution; S2. Initiator D is added to the electrolyte salt solution and stirred until dissolved to obtain a polymerization solution. S3 assembles the solution to be polymerized with the positive and negative electrodes to form a lithium-ion battery, wherein the electrolyte solution undergoes an in-situ polymerization reaction inside the battery to form a solid electrolyte.

2. The preparation method according to claim 1, characterized in that, In step S1, the first monomer A is one or more of ethylene oxide, propylene oxide, 1,3-dioxolane, polyethylene glycol diacrylate, and polyethylene glycol methyl ether acrylate.

3. The preparation method according to claim 1, characterized in that, In step S1, the second monomer B is a cyclic carbonate monomer or a linear carbonate monomer; the cyclic carbonate monomer is one or more of vinylene carbonate, ethylene ethylene carbonate, ethylene carbonate, propylene carbonate, trimethylene carbonate, and 2-ethoxycarbonyl-2-methyltrimethylene carbonate; the linear carbonate monomer is any one or a combination of propargyl methyl carbonate, allyl methyl carbonate, ethyl allyl carbonate, diallyl pyrocarbonate, diallyl carbonate, allyl chloroformate, allyl phenyl carbonate, allyl ethyl carbonate, allyl oxalate, allyl acetate, and allyl isonicotinate.

4. The preparation method according to claim 1, characterized in that, The lithium salt C mentioned in step S1 is any one or more of lithium difluorooxalate borate, lithium dioxalate borate, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium hexafluorophosphate, and lithium bis(fluorosulfonyl)imide. combine.

5. The preparation method according to claim 1, characterized in that, The initiator D mentioned in step S2 is any one of benzoyl peroxide, dicumyl peroxide, hydrogen peroxide, 2,2'-azobis(isobutyronitrile), and azobisisoheptanenitrile.

6. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of the first monomer A to the second monomer B is (0.1-10):

1.

7. The preparation method according to claim 1, characterized in that, In step S2, the concentration of lithium salt in the polymerization solution is 0.2-5 mol / L, the concentration of initiator D is 0.1-1 mol / L, the mass percentage of monomer A is 60-95%, and the mass percentage of monomer B is 5-40%.

8. The preparation method according to claim 1, characterized in that, The in-situ polymerization reaction in step S3 is carried out at a temperature of 30-90℃ and for a polymerization time of 6-30h.

9. A solid-state battery, characterized in that... It includes a positive electrode, a negative electrode, a separator, and a solid electrolyte prepared by any of the methods described in claims 1-8.

10. The solid-state battery according to claim 9, characterized in that, The positive electrode is any one of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, copper sheet, and stainless steel; the negative electrode is any one of lithium metal, silicon oxide, stainless steel, and graphite.

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