Flexible solid-state electrolyte and method for preparing the same, secondary battery

Abstract

The application belongs to the technical field of batteries, and particularly relates to a flexible solid electrolyte and a preparation method thereof, and a secondary battery. The preparation method of the flexible solid electrolyte comprises the following steps: mixing and processing a polymer monomer, semiconductor nanoparticles, ion conductor nanoparticles, an alkali metal salt and a polymer initiator to obtain a precursor slurry; the polymer monomer is selected from monomers containing a polar group and a single-end unsaturated bond; and the precursor slurry is subjected to polymerization processing to obtain a molded flexible solid electrolyte. The preparation method of the flexible solid electrolyte of the application obtains a long-chain comb-shaped polymer with a linear carbon chain formed by unsaturated bond addition polymerization as a main chain and a monomer containing a polar group as a branch chain, and the long-chain comb-shaped polymer has excellent flexibility, elasticity, ion conductivity, voltage resistance and pyrolysis temperature and other characteristics.

Description

Technical Field

[0001] This application belongs to the field of battery technology, and particularly relates to a flexible solid electrolyte and its preparation method, as well as a secondary battery. Background Technology

[0002] Lithium-ion batteries, due to their high energy density and good safety, have achieved tremendous development in mobile devices, electric vehicles, smart grids, and other fields. In recent years, the consumer market's increasingly urgent demand for high-energy-density lithium batteries has greatly promoted research and development in this field. However, in the development of high-capacity lithium rechargeable batteries, a series of phenomena, such as short circuits caused by dendritic crystal growth and the shuttle effect in lithium-sulfur batteries, have led to poor safety and cycle performance of rechargeable batteries, limiting their development and application. On the other hand, future mobile electronic devices have shown a clear trend towards wearable and implantable designs. In current research, various flexible and stretchable electronic devices have been developed, and a large number of research results on flexible batteries have emerged in the energy storage field. However, in real life, because wearable electronic devices need to withstand irregular strain in multiple directions, conventional flexible energy storage devices are prone to structural fractures, contact failures, and other adverse results under such working environments. In addition, the large volume variations of high-capacity materials such as Li (3860 mAh / g) and Si (4200 mAh / g) will cause considerable internal stress changes in the battery's internal structure.

[0003] Currently, the realization of elastic solid-state electrolytes is based on organic materials. Gel polymer electrolytes achieve elasticity by constructing an elastic gel framework; solid polymer electrolytes achieve elasticity by introducing elastic segments. However, purely inorganic solid electrolytes cannot achieve elastic properties due to the rigid structure of the material itself. Gel polymer electrolytes, due to the presence of liquid components, have high chemical activity, low decomposition voltage, and poor high-temperature resistance, making them difficult to apply in many high-voltage cathode battery systems. Furthermore, the gel framework cannot guarantee the fixation of the liquid components, easily leading to leakage, liquid phase evaporation, and other problems, resulting in decreased energy density and safety. Research on solid polymer electrolytes has focused heavily on how to enhance material strength to suppress lithium dendrite growth, but the introduction of elasticity means that elastic polymers cannot physically restrict lithium dendrite growth. Conventional solid electrolytes have extremely poor elasticity, low ionic conductivity, poor resistance to deformation, and are prone to breakage. Summary of the Invention

[0004] The purpose of this application is to provide a flexible solid electrolyte and its preparation method, as well as a secondary battery, which aims to solve, to some extent, the problems of poor elasticity and low ionic conductivity of existing flexible solid electrolytes.

[0005] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides a method for preparing a flexible solid electrolyte, comprising the following steps:

[0007] A precursor slurry is obtained by mixing polymer monomers, semiconductor nanoparticles, ion conductor nanoparticles, alkali metal salts, and polymer initiators; the polymer monomers are selected from monomers containing polar groups and single-terminal unsaturated bonds.

[0008] The precursor slurry is polymerized to obtain a molded flexible solid electrolyte.

[0009] Further, the mixing process includes the following steps: mixing the polymer monomer, the alkali metal salt and the polymer initiator, and then adding the semiconductor nanoparticles and the ion conductor nanoparticles under dispersion conditions of pH 5-8 and rotation speed of 800-1600 r / min for 4-6 hours to obtain the precursor slurry.

[0010] Furthermore, the step of polymerizing the precursor slurry includes: injecting the precursor slurry into a molding die containing a flexible skeleton, initiating a polymerization reaction in the precursor slurry, and drying it to obtain the molded flexible solid electrolyte.

[0011] Furthermore, the polymer monomer is selected from at least one of the following: polyethylene glycol monomers, acrylate monomers, acrylate monomers, nitrile monomers, sulfonic acid monomers, and urethane monomers.

[0012] Furthermore, the polar group is selected from at least one of the following: -O-, =O, -S-, -N-, -P-, C=O, C≡N.

[0013] Furthermore, the mass-average molecular weight of the polymer monomer is 360 to 5000.

[0014] Furthermore, the semiconductor nanoparticles have at least one dimension with a scale of 10–200 nm.

[0015] Furthermore, the semiconductor nanoparticles include at least one of Si, Ge, Se, GaAs, GaP, AlAs, lnSb, InN, and InP.

[0016] Furthermore, the mass ratio of the semiconductor nanoparticles to the polymer monomers is (1-10):(90-99).

[0017] Furthermore, the polymer monomer is selected from at least one of the following: polyethylene glycol methyl ether methacrylate, methoxy polyethylene glycol acrylate, acrylic acid, methyl acrylate, acrylonitrile, sodium propylene sulfonate, and acrylamide.

[0018] Furthermore, the ion conductor nanoparticles have at least one dimension with a scale of 50–200 nm.

[0019] Furthermore, the ion-conducting nanoparticles include: TiO2, Al2O3, Fe3O4, LLZO, LLZTO, LGPS, and Na3Zr2Si2PO4. 12 At least one of them.

[0020] Furthermore, the mass ratio of the ion conductor nanoparticles to the polymer monomer is (2-20):(80-98).

[0021] Furthermore, the alkali metal salt includes: Li + Na + K + Ca 2+ Mg 2+ Zn 2+ Al 3+ It contains at least one metal cation and at least one anion selected from hexafluorophosphate, halide anion, bis(trifluorosulfonyl)imide, bis(fluorosulfonyl)imide, oxalate, tetrafluoroborate, dioxaloborate, and perchlorate.

[0022] Furthermore, the molar ratio of the metal cation in the alkali metal salt to the polar group in the polymer monomer is 1:(8-40).

[0023] Furthermore, the polymer initiator is selected from photoinitiators; the conditions for initiating the polymerization reaction of the precursor slurry include irradiation treatment for 5 to 30 minutes under a light wavelength of 400 to 760 nm.

[0024] Furthermore, the polymer initiator is selected from: thermal initiators; the conditions for initiating the polymerization reaction of the precursor slurry include: heating at a temperature of 50 to 200°C for 10 to 120 minutes.

[0025] Furthermore, the molar ratio of the initiator to the unsaturated bonds in the polymer monomer is (1-5):(95-99).

[0026] Furthermore, the flexible skeleton includes at least one of woven fabric, nonwoven fabric, and three-dimensional porous rubber.

[0027] Furthermore, the porosity of the flexible skeleton is 50% to 90%.

[0028] Furthermore, the flexible skeleton has a tensile fracture rate of 100% to 400% in at least one two-dimensional direction.

[0029] Further, the photoinitiator is selected from at least one of the following: 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, methyl benzoylformate, and methyl benzoylformate.

[0030] Further, the thermal initiator is selected from: benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl peroxide, tert-butyl valerate peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxide, dicyclohexyl peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide / sucrose, tert-butyl hydroperoxide / sodium hydroxide, tert-butyl hydroperoxide / pyrosulfite. At least one of the following: sodium, benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, potassium persulfate / sodium bisulfite, hydrogen peroxide / tartaric acid, hydrogen peroxide / sodium formaldehyde sulfoxylate, ammonium persulfate / ferrous sulfate, hydrogen peroxide / ferrous sulfate, benzoyl peroxide / N,N-diethylaniline, benzoyl peroxide / ferrous pyrophosphate, potassium persulfate / silver nitrate, persulfate / thiol, cumene hydrogen peroxide / ferrous chloride, potassium persulfate / ferrous chloride, hydrogen peroxide / ferrous chloride, and cumene hydrogen peroxide / tetraethyleneimine.

[0031] Furthermore, the drying conditions include drying for 6 to 48 hours under vacuum conditions at a temperature of 50 to 200°C.

[0032] Secondly, this application provides a flexible solid electrolyte, which includes a polymer body and semiconductor nanoparticles, ion conductor nanoparticles and alkali metal ions incorporated in the polymer body.

[0033] Thirdly, this application provides a secondary battery, which includes a flexible solid electrolyte prepared by the above method, or the flexible solid electrolyte described above.

[0034] The method for preparing a flexible solid electrolyte provided in the first aspect of this application involves mixing polymer monomers, semiconductor nanoparticles, ion-conducting nanoparticles, alkali metal salts, and a polymer initiator. The precursor slurry is then polymerized. The polymer monomers are interconnected via addition polymerization, initiated by the initiator, using single-ended unsaturated bonds to form a long-chain comb-shaped polymer with a linear carbon chain as the main chain and monomers containing polar groups as branches. This polymer is an ultra-long linear molecule with large flexible chains and low inter-chain cross-linking, giving the solid electrolyte excellent elasticity and flexibility. Even at room temperature, it retains good activity and elasticity, ensuring high ionic conductivity and stretchability. Furthermore, free radicals readily form on the surface of the semiconductor nanoparticles, inducing in-situ catalytic polymerization of unsaturated bonds in the polymer monomers. This allows the semiconductor nanoparticles to directly bond to the long-chain comb-shaped polymer, forming a dense interfacial bond and enhancing the tensile strength of the solid electrolyte. The free radicals on the surface of the semiconductor nanoparticles also facilitate the formation of rapid ion transport channels, aiding in improved ion conductivity, achieving uniform deposition, and inhibiting lithium dendrite growth. Meanwhile, the polar groups contained in the single-end unsaturated oligomeric branches of long-chain comb-shaped polymers can complex with alkali metal ions in alkali metal salts, thereby improving the ionic conductivity of solid electrolytes. Furthermore, ion-conducting nanoparticles in situ doped into flexible solid electrolytes effectively enhance the ionic conductivity of the flexible solid electrolytes by constructing fast ion transport channels on the surface and in the bulk phase.

[0035] The flexible solid-state electrolyte provided in the second aspect of this application comprises a polymer matrix and semiconductor nanoparticles, ion-conducting nanoparticles, and alkali metal ions incorporated within the polymer matrix. It not only possesses excellent flexibility, elasticity, and high ionic conductivity—with a polymer lithium-ion conductivity exceeding 10⁻⁴ S / cm at room temperature—but also withstands a wider voltage range, exceeding 7V, thus freeing the battery's energy density from the limitations of the solid-state electrolyte itself. Furthermore, the flexible solid-state electrolyte has a pyrolysis temperature as high as 300°C, effectively expanding the battery's operating temperature range and enhancing battery safety.

[0036] The secondary battery provided in the third aspect of this application improves the capacity retention, cycle stability and safety performance of the secondary battery by including the aforementioned flexible solid electrolyte with excellent flexibility, elasticity, ionic conductivity, withstand voltage and pyrolysis temperature. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is the XRD analysis diagram of the flexible solid electrolyte provided in Embodiment 14 of this application;

[0039] Figure 2 This is an LSV test curve of the flexible solid electrolyte provided in Embodiment 14 of this application;

[0040] Figure 3 This is a thermogravimetric analysis curve of the flexible solid electrolyte provided in Embodiment 14 of this application;

[0041] Figure 4 This is an elastic tensile test diagram of the flexible solid electrolyte provided in Embodiment 14 of this application;

[0042] Figure 5 This is a schematic diagram of the structure of the flexible solid electrolyte provided in the embodiments of this application. Detailed Implementation

[0043] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0045] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0046] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0047] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0048] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0049] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0050] The first aspect of this application provides a method for preparing a flexible solid electrolyte, comprising the following steps:

[0051] S10. The polymer monomer, semiconductor nanoparticles, ion conductor nanoparticles, alkali metal salt and polymer initiator are mixed to obtain a precursor slurry; the polymer monomer is selected from monomers containing polar groups and single-terminal unsaturated bonds;

[0052] S20. The precursor slurry is polymerized to obtain a molded flexible solid electrolyte.

[0053] The method for preparing a flexible solid electrolyte provided in the first aspect of this application involves mixing polymer monomers, semiconductor nanoparticles, ion-conducting nanoparticles, alkali metal salts, and a polymer initiator. The precursor slurry is then polymerized. The polymer monomers are interconnected via addition polymerization, initiated by the initiator, using single-ended unsaturated bonds to form a long-chain comb-shaped polymer with a linear carbon chain as the main chain and monomers containing polar groups as branches. This polymer is an ultra-long linear molecule with large flexible chains and low inter-chain cross-linking, giving the solid electrolyte excellent elasticity and flexibility. Even at room temperature, it retains good activity and elasticity, ensuring high ionic conductivity and stretchability. Furthermore, free radicals readily form on the surface of the semiconductor nanoparticles, inducing in-situ catalytic polymerization of unsaturated bonds in the polymer monomers. This allows the semiconductor nanoparticles to directly bond to the long-chain comb-shaped polymer, forming a dense interfacial bond and enhancing the tensile strength of the solid electrolyte. The free radicals on the surface of the semiconductor nanoparticles also facilitate the formation of rapid ion transport channels, aiding in improved ion conductivity, achieving uniform deposition, and inhibiting lithium dendrite growth. Meanwhile, the polar groups contained in the single-end unsaturated oligomeric branches of the long-chain comb-shaped polymer can complex with alkali metal ions in alkali metal salts, thereby improving the ionic conductivity of the solid electrolyte. Furthermore, ion-conducting nanoparticles in situ doped into the flexible solid electrolyte effectively enhance its ionic conductivity by constructing fast ion transport channels on the surface and in the bulk phase. The flexible solid electrolyte prepared in the embodiments of this application exhibits excellent flexibility, elasticity, ionic conductivity, withstand voltage, and pyrolysis temperature.

[0054] The polymer monomers used in this application are monomers containing polar groups and single-ended unsaturated bonds. These monomers are interconnected via addition polymerization through single-ended unsaturated bonds, forming a long-chain comb-type polymer with a linear carbon chain as the main chain and monomers containing polar groups as branches. This process ensures the polymer's elasticity, flexibility, and ionic conductivity. If a double-ended unsaturated polymer (i.e., one with carbon-carbon double bonds at both ends) is used, both ends will participate in the polymerization process during free radical polymerization, forming crosslinks. While increased crosslinking improves polymer strength to some extent, it also reduces the mobility of chain segments. The crosslinking of double-ended unsaturated monomers forms "bridges" connecting different chain segments. The ion conductivity of these "bridges" is far lower than that of the linear carbon chain "bridges" in the long-chain comb-type polymer of this application, thus reducing ionic conductivity.

[0055] Furthermore, the long-chain comb-shaped polymer prepared in this application, with a linear carbon chain formed by unsaturated bond addition polymerization as the main chain and monomers containing polar groups as branches, improves the withstand voltage of the flexible solid-state electrolyte, enabling it to withstand a higher voltage range and be applied in many high-voltage cathode battery systems. Simultaneously, the long-chain comb-shaped polymer increases the pyrolysis temperature of the flexible solid-state electrolyte, effectively expanding the battery's operating temperature range and improving battery safety. The long-chain comb-shaped polymer prepared in this application provides elasticity through the main chain and ion conductivity through the branches, while introducing semiconductor nanoparticles to increase the strength and toughness of the composite material without reducing ion conductivity. Moreover, the long-chain comb-shaped polymer prepared in this application is a highly amorphous polymer material with virtually no crystallinity, making the application of all-solid-state electrolytes at room temperature possible.

[0056] In some embodiments, in step S10 above, the polar groups in the polymer monomer are selected from at least one of -O-, =O, -S-, -N-, -P-, C=O, and C≡N. These polar groups can coordinate with alkali metal ions to complex the alkali metal ions onto the generated long-chain comb-shaped polymer, thereby providing the ionic conductivity of the solid electrolyte.

[0057] In some embodiments, the polymer monomers are selected from at least one of polyethylene glycol monomers, acrylate monomers, acrylate monomers, nitrile monomers, sulfonic acid monomers, and urethane monomers. These polymer monomers simultaneously contain polar groups and single-ended unsaturated bonds. The single-ended unsaturated bonds can be interconnected via addition polymerization to form a long-chain comb-like polymer with a linear carbon chain formed by the addition polymerization of unsaturated bonds as the main chain and monomers containing polar groups as branches. The linear carbon-carbon main chain restricts the movement of the branched oligomers, and the flexible long chains formed by the linear carbon-carbon main chain are essentially uncrosslinked, with a low degree of crosslinking between molecular chains. At room temperature, it still exhibits good mobility and elasticity, making the polymer an ultra-long linear molecule with large flexible chains. This endows the solid electrolyte with excellent elasticity and flexibility, ensuring high ionic conductivity and stretchability. In addition, the embodiments of this application may simultaneously add the above-mentioned polymer monomers, and by using monomers with different molecular weights for blending polymerization, the prepared long-chain comb-shaped molecular polymer material contains branches of different sizes, making the organic macromolecular branches disordered, reducing the overall crystallinity of the polymer, and improving the chain segment mobility.

[0058] In some specific embodiments, the polymer monomers are selected from: polyethylene glycol monomers, such as polyethylene glycol methyl ether methacrylate, methoxy polyethylene glycol acrylate, etc.; acrylate or acrylate monomers, such as acrylic acid, methyl acrylate, etc.; nitrile monomers, such as acrylonitrile; sulfonic acid monomers, such as sodium propylene sulfonate; and urethane monomers, such as acrylamide. These polymer monomers have high chain flexibility, which is beneficial for transporting lithium ions and other ions; they also have high dielectric constants and strong ion solvation capabilities, resulting in high ionic conductivity.

[0059] In some preferred embodiments, during the preparation of the flexible solid electrolyte of this application, other conventional polymer materials such as polyethylene glycol, polyacrylonitrile, and polyethyleneimine can also be added. The long-chain comb-shaped polymer obtained by addition polymerization of the single-end unsaturated bonds in the polymer monomer can be blended with these conventional polymer materials. Through steric hindrance, charge interaction, and other means, the conventional polymer is distributed between the chains of the polymer materials of this application, so that when the addition polymer becomes taut during the stretching of the solid electrolyte, it plays an auxiliary role in inter-chain ion conduction.

[0060] In some embodiments, the mass-average molecular weight of the polymer monomer is 360 to 5000. If the molecular weight of the monomer is too large, it will increase the glass temperature of the long-chain comb-type polymer and reduce its flexibility.

[0061] In some embodiments, the long-chain comb-shaped polymers obtained by addition polymerization of the polymer monomers of this application through single-end unsaturated bonds have a linear molecular structure, wherein the proportion of nonlinearity is less than 5%. The linear polymer chains have low cross-linking, and still exhibit good mobility and elasticity at room temperature. In some embodiments, the elongation at break of the long-chain comb-shaped polymer is not less than 150%, and it can recover its original shape after stretching, further ensuring the elasticity and flexibility of the polymer. In some specific embodiments, the long-chain comb-shaped polymers may also contain small amounts of ionic liquids, fluoroethylene carbonate (FEC), and other additives to provide auxiliary properties such as stabilization, cross-linking, and flame retardancy.

[0062] In some embodiments, the semiconductor nanoparticles have at least one dimension with a size of 10–200 nm. Semiconductor nanoparticles of this size have a larger effective specific surface area, which is beneficial for the in-situ polymerization of polymer monomers on the surface of the semiconductor nanoparticles, forming a dense interfacial bond and better enhancing the tensile strength of the solid electrolyte. The embodiments of this application do not specifically limit the shape of the semiconductor material; it can be in a nanoscale state such as nanospheres, nanowires, or nanosheets.

[0063] In some embodiments, the semiconductor nanoparticles include at least one of Si, Ge, Se, GaAs, GaP, AlAs, lnSb, InN, and InP. These semiconductor nanoparticles readily form free radicals on their surfaces, inducing in-situ catalytic polymerization of unsaturated bonds in polymer monomers. In some preferred embodiments, the surface of the semiconductor nanoparticles includes a natural surface (i.e., an unmodified pure semiconductor surface), contains hydrogen bonds, and contains hydroxyl groups, etc., to better achieve surface catalytic polymerization of single-terminal unsaturated double bonds in monomers to form long-chain comb-shaped polymers, and to tightly bind ion-conducting nanoparticles, alkali metal ions, etc., within the polymer, thereby improving the ionic conductivity, elasticity, flexibility, and other properties of the solid electrolyte. In a further preferred embodiment, the surface of the semiconductor nanoparticles can be modified with methyl or amino groups to further improve the in-situ polymerization efficiency of single-terminal unsaturated double bonds in monomers.

[0064] In some specific embodiments, silicon nanoparticles are used as semiconductor nanoparticles. Silicon free radicals are readily formed on the silicon surface, and these nanoparticles are introduced to construct an internal reinforcing network. Specifically, the Si-OH functional groups present on the silicon surface readily undergo dehydrogenation or even dehydroxylation under external factors, forming dangling Si(O)· bonds. Combined with these dangling bonds, this easily induces the polymerization of monounsaturated double bonds on the silicon surface. This polymerization method allows the polymer to directly connect with silicon, forming a tight interfacial bond, which directly enhances the tensile strength of the solid electrolyte. Simultaneously, the abundant oxide surface also facilitates the formation of rapid ion transport channels, aiding in improved ion conductivity without reducing the tensile strength of the composite material.

[0065] In some embodiments, the mass ratio of semiconductor nanoparticles to polymer monomers is (1-10):(90-99). This ratio ensures efficient in-situ polymerization of monomers on the surface of semiconductor nanoparticles, effectively enhancing the tensile strength of the solid electrolyte and improving its ionic conductivity. However, excessive addition of semiconductor nanoparticles reduces the content of polymers in the solid electrolyte, thereby decreasing its overall elasticity and flexibility.

[0066] In some embodiments, the ion conductor nanoparticles have at least one dimension with a size of 50–200 nm. This size of ion conductor nanoparticles results in a small particle size and a large effective specific surface area, which is beneficial for binding into the polymer of the solid electrolyte and improving the ion conductivity of the solid electrolyte.

[0067] In some embodiments, ion-conducting nanoparticles include: inert metal oxides such as TiO2, Al2O3, and Fe3O4; lithium-ion conductive ceramics such as LLZO, LLZTO, and LGPS; and Na3Zr2Si2PO4. 12It is at least one of other fast ion conductors; these ion conductor nanoparticles have excellent ion conduction properties and can effectively improve the ion conductivity of solid electrolytes.

[0068] In some embodiments, the mass ratio of ion conductor nanoparticles to polymer monomers is (2-20):(80-98). This ratio of ion conductor nanoparticles can effectively improve the ion conductivity of solid electrolytes. If the amount of ion conductor nanoparticles added is too high, it will reduce the content of polymer in the solid electrolyte, thereby reducing the overall elasticity and flexibility of the solid electrolyte.

[0069] In some embodiments, the alkali metal salt includes: Li + Na + K + Ca 2+ Mg 2+ Zn 2+ Al 3+ The alkali metal salt contains at least one metal cation and at least one anion selected from hexafluorophosphate, halide anion, bis(trifluorosulfonyl)imide, bis(fluorosulfonyl)imide, oxalate, tetrafluoroborate, dioxaloborate, and perchlorate. In the embodiments of this application, the alkali metal salt containing these metal cations and anions can be dissociated by polar groups in the polymer, and the polar groups contained in the single-end unsaturated oligomeric branches of the polymer can complex with the alkali metal ions in the alkali metal salt, complexing the alkali metal ions onto the generated long-chain comb-shaped polymer, thereby better improving the ionic conductivity of the solid electrolyte.

[0070] In some embodiments, the molar ratio of the metal cation in the alkali metal salt to the polar group in the polymer monomer is 1:(8-40). This ratio of metal cation can effectively improve the ionic conductivity of the flexible solid electrolyte. If the content of the alkali metal salt is too high or too low, the ionic conductivity will be too low.

[0071] In some embodiments, step S10 above includes the following steps: after mixing the polymer monomer, alkali metal salt and polymer initiator, semiconductor nanoparticles and ionic conductor nanoparticles are added and mixed for 4 to 6 hours under dispersion conditions of pH 5 to 8 and rotation speed of 800 to 1600 r / min. The pH value is adjusted to 5 to 8 by using highly volatile acids and bases such as ammonia, acetic acid and formic acid, which is conducive to the generation of free radicals on the surface of semiconductor nanoparticles, thereby facilitating the in-situ polymerization of monomers containing polar groups and single-ended unsaturated bonds on the surface of semiconductor nanoparticles. The rotation speed of 800 to 1600 r / min ensures that the semiconductor nanoparticles and ionic conductor nanoparticles are fully and uniformly mixed with the polymer monomer, alkali metal salt and polymer initiator, which is conducive to balancing the in-situ polymerization rate of monomers on the surface of semiconductor nanoparticles, avoiding uneven monomer polymerization rate in the precursor slurry, avoiding local rapid polymerization of monomers leading to polymer solidification, and reducing the flexibility and elasticity of the solid electrolyte. In some embodiments, the mixing process can also be aided by water bath ultrasound, cell disruptor ultrasound, etc., to help the raw material components mix more evenly. Water bath ultrasound is preferably performed for about 30 minutes. The mixing process in this application embodiment is based on the premise that the raw material components are evenly distributed and no sedimentation occurs within 24 hours.

[0072] In some embodiments, the step of polymerizing the precursor slurry in step S20 includes: injecting the precursor slurry into a molding die containing a flexible skeleton, initiating the polymerization reaction of the precursor slurry according to the initiation conditions of the initiator, and drying the slurry to obtain the molded flexible solid electrolyte.

[0073] In some embodiments, the polymer initiator is selected from: photoinitiators; the conditions for initiating the polymerization reaction of the precursor slurry include: irradiation treatment at a light wavelength of 400-760 nm for 5-30 minutes; under these light conditions, the photoinitiator can initiate the in-situ polymerization of monomers containing polar groups and single-ended unsaturated bonds on the surface of semiconductor nanoparticles to form long-chain comb-shaped polymers. In some specific embodiments, the photoinitiator is selected from at least one of the following: 1173 (2-hydroxy-2-methyl-1-phenyl-1-propanone), 184 (1-hydroxycyclohexylphenyl ketone), 907 (2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone), TPO (diphenyl-(2,4,6-trimethylbenzoyl)phosphine), TPO-L (ethyl 2,4,6-trimethylbenzoylphenylphosphonate), 659 (methyl benzoylformate), and MBF (methyl benzoylformate). These photoinitiators, under suitable illumination conditions, can initiate the in-situ polymerization of monomers containing polar groups and single-ended unsaturated bonds on the surface of semiconductor nanoparticles to form long-chain comb-shaped polymers. In some specific embodiments, photoinitiator 184 is used, a 400W 395nm wavelength ultraviolet lamp is employed, the lamp samples are spaced 15cm apart, and the curing time is 15min.

[0074] In some embodiments, the polymer initiator is selected from: thermal initiators; the conditions for initiating the polymerization reaction of the precursor slurry include: heating at a temperature of 50 to 200°C for 10 to 120 minutes; under these heating conditions, the thermal initiator can initiate the in-situ polymerization of monomers containing polar groups and single-ended unsaturated bonds on the surface of semiconductor nanoparticles to form long-chain comb-shaped polymers.

[0075] In some specific embodiments, the thermal initiator is selected from: organic peroxides, such as benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl peroxide, tert-butyl pentanoate peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxide, dicyclohexyl peroxide, etc.; inorganic peroxides, such as potassium persulfate, sodium persulfate, ammonium persulfate, etc.; azo initiators, such as azobisisobutyronitrile, azobisisoheptanenitrile, etc.; redox pair initiators; and free radical initiator systems in the form of mixtures, such as benzoyl peroxide / sucrose, tert-butyl hydroperoxide / sodium thiosulfate, tert-butyl hydroperoxide / sodium metabisulfite, etc. Benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, potassium persulfate / sodium bisulfite, hydrogen peroxide / tartaric acid, hydrogen peroxide / sodium formaldehyde sulfoxylate, ammonium persulfate / ferrous sulfate, hydrogen peroxide / ferrous sulfate, benzoyl peroxide / N,N-diethylaniline, benzoyl peroxide / ferrous pyrophosphate, potassium persulfate / silver nitrate, persulfate / thiol, cumene hydroperoxide / ferrous chloride, potassium persulfate / ferrous chloride, hydrogen peroxide / ferrous chloride, and cumene hydroperoxide / tetraethyleneimine are all thermal initiators that, under suitable heating conditions, can initiate the in-situ polymerization of monomers containing polar groups and single-ended unsaturated bonds on the surface of semiconductor nanoparticles to form long-chain comb-shaped polymers. In some specific embodiments, diisopropyl peroxide dicarbonate is used as the initiator, added at 80°C, and heated for 60 min.

[0076] In some embodiments, the molar ratio of the initiator to the unsaturated bonds in the polymer monomer is (1-5):(95-99). This ratio of initiator effectively ensures that the polymer monomers are fully cross-linked and polymerized. If the content is too low, it will not be conducive to the cross-linking and polymerization between polymer monomers. If the content is too high, the excessive initiator will reduce the elasticity and flexibility of the solid electrolyte and will also affect the ionic conductivity within the solid electrolyte.

[0077] In some embodiments, the solid electrolyte further includes a flexible framework, which may be at least one of woven fabric, nonwoven fabric, or three-dimensional porous rubber (such as thermoplastic polyurethane elastomer TPU). These flexible frameworks serve as auxiliary support structures for the flexible solid electrolyte, preventing the polymer from being compressed during battery assembly and causing it to reach a high degree of stretching in its initial state. In some embodiments, the size of the flexible framework can be selected according to the actual application of the solid electrolyte. In some specific embodiments, the thickness of the flexible framework is less than 200 μm.

[0078] In some embodiments, the porosity of the flexible skeleton is 50% to 90%. The high porosity of the flexible skeleton provides a better auxiliary support structure for the molding of polymers, and avoids the problem that an excessively high proportion of the flexible skeleton in the solid electrolyte will affect the elasticity, flexibility and ionic conductivity of the solid electrolyte.

[0079] In some embodiments, the tensile fracture rate of the flexible skeleton reaches 100% to 400% in at least one two-dimensional direction, and this tensile fracture rate of the flexible skeleton reduces the influence of the flexible skeleton on the flexibility and elasticity of the solid electrolyte.

[0080] In some embodiments, after injecting the precursor slurry into a molding die containing a flexible skeleton, the precursor slurry undergoes a polymerization reaction. The flexible solid electrolyte is then removed from the die in any appropriate manner and dried for 6 to 48 hours under vacuum conditions at a temperature of 50 to 200°C to remove excess solvent from the precursor slurry system and to stabilize the flexible solid electrolyte in its molding process.

[0081] In some embodiments, the method of injecting the precursor slurry into a molding die containing a flexible skeleton includes, but is not limited to, casting and coating methods. The precursor slurry can also be spatially constrained in any way to facilitate the precursor slurry to be molded into a three-dimensional or planar structure according to the shape and size required for actual application, so as to meet the subsequent application requirements.

[0082] Accordingly, a second aspect of this application provides a flexible solid-state electrolyte, comprising a polymer matrix and semiconductor nanoparticles, ion-conducting nanoparticles, and alkali metal ions bonded within the polymer matrix. The flexible solid-state electrolyte provided in this second aspect, comprising a polymer matrix and semiconductor nanoparticles, ion-conducting nanoparticles, and alkali metal ions bonded within the polymer matrix, not only possesses excellent flexibility, elasticity, and high ion conductivity, but also exhibits a polymer lithium-ion conductivity exceeding 10 at room temperature. -4 S / cm; moreover, the flexible solid electrolyte can withstand a wider voltage range, withstanding voltages above 7V, so that the battery energy density is not limited by the solid electrolyte itself. At the same time, the pyrolysis temperature of the flexible solid electrolyte is as high as 300℃, which effectively improves the battery's operating temperature range and enhances battery safety.

[0083] The flexible solid electrolyte of this application embodiment is prepared by the method described in the above embodiment.

[0084] In some embodiments, a schematic diagram of the flexible solid electrolyte is shown in the attached figure. Figure 5As shown, polymer monomers are interconnected by addition polymerization via an initiator to initiate single-ended unsaturated bonds, forming a long-chain comb-shaped polymer matrix. This matrix has a linear carbon chain formed by addition polymerization of unsaturated bonds as the main chain and monomers containing polar groups as branches. Semiconductor nanoparticles are directly bonded to the long-chain comb-shaped polymer. Alkali metal cations in alkali metal salts complex with polar groups in the branches. Alkali metal anions and ion conductor nanoparticles are in situ doped into the flexible solid electrolyte.

[0085] A third aspect of this application provides a secondary battery comprising a flexible solid electrolyte prepared by the above method or the flexible solid electrolyte described above.

[0086] The secondary battery provided in the third aspect of this application improves the capacity retention, cycle stability and safety performance of the secondary battery by including the aforementioned flexible solid electrolyte with excellent flexibility, elasticity, ionic conductivity, withstand voltage and pyrolysis temperature.

[0087] To enable those skilled in the art to clearly understand the above-described implementation details and operations, and to highlight the significant improvements in the performance of the flexible solid electrolyte and its preparation method, as well as the secondary battery, the following examples illustrate the above technical solutions.

[0088] For ease of description, in the embodiments of this application, methoxy polyethylene glycol acrylate is referred to as MPEGA, polyethylene glycol methyl ether methacrylate as MPEG-Ma, polyethylene glycol diacrylate as PEGDA, and polyethylene glycol dimethacrylate as PEGD-Ma. The numbers following the English descriptions are molecular weights, such as MPEGA480.

[0089] The following method for testing room temperature ionic conductivity is as follows: Cut the electrolyte membrane into a circular piece with a diameter of 16 mm, and sandwich it between two stainless steel sheets to test the room temperature ionic conductivity.

[0090] The following voltage decomposition is based on the condition that the current per unit area is greater than 50 mA / cm² under linear sweep voltammetry (LSV) testing. 2 .

[0091] The following decomposition temperatures are based on the condition that the weight loss exceeds 10% in the thermogravimetric test. In the tensile fracture test, the tensile fracture rate is calibrated with fracture as the final point and 10% as the smallest unit.

[0092] Example 1

[0093] A flexible solid electrolyte is prepared by the following steps: 5g of polymer monomer MPEGA480 is taken, and an appropriate amount of LiTFSI is added at a mass ratio of 25% of the total polymer monomer mass. Simultaneously, a photoinitiator 184 is added at a molar equivalent of 1% of the ethylene glycol monomer. The mixture is magnetically stirred for 1 hour and sonicated for 15 minutes to ensure uniform mixing. The solution is then poured into a mold and irradiated with a 400W ultraviolet lamp for 10 minutes, with the lamp 15cm away from the mold. After the solution solidifies, it is removed from the mold and placed in an 80℃ oven for vacuum drying for 12 hours to obtain the flexible solid electrolyte.

[0094] After drying, the flexible solid electrolyte membrane was removed, cut into 16mm diameter discs, and sandwiched between two stainless steel sheets to test the room temperature ionic conductivity.

[0095] Meanwhile, a flexible solid electrolyte membrane with a diameter of 16mm was cut and assembled into a coin cell under a nitrogen atmosphere. One end was a lithium sheet and the other end was a stainless steel sheet. The LSV was tested at a scan rate of 1mV / s on an electrochemical workstation.

[0096] Take 0.2g of flexible solid electrolyte and place it in a thermogravimetric crucible for thermogravimetric analysis.

[0097] A 7cm×2cm×0.02cm flexible solid electrolyte cuboid was subjected to a fracture test on a tensile testing machine. The fracture point was taken as the final calibration point, and 10% was taken as the smallest unit.

[0098] Examples 2-8

[0099] With the type of polymer monomer as the variable, the polymer monomers used in each embodiment are shown in Table 1 below. The preparation and testing methods are the same as in Example 1, as detailed in Table 1 below:

[0100] Table 1

[0101]

[0102] As can be seen from the test results in Table 1 above, the polymer monomers in the flexible solid electrolyte of this application cross-link to form a high molecular polymer with excellent elasticity and flexibility, and a high room temperature decomposition temperature and high ionic conductivity.

[0103] Examples 9-12

[0104] Using Si nanoparticles as the controlled variable, MPEGA480 was used as the organic precursor, and LiTFSI with a total mass ratio of 25% was selected as the lithium salt. The preparation and testing methods were the same as in Example 1, as shown in Table 2 below:

[0105] Table 2

[0106]

[0107]

[0108] As can be seen from the test results in Table 2 above, the addition of silicon semiconductor nanoparticles to the flexible solid electrolyte significantly improves the flexibility and elasticity of the solid electrolyte, as well as the room temperature ionic conductivity, and the decomposition voltage is greater than 7V.

[0109] Examples 13-17

[0110] Using ion-conducting nanoparticles as the controlled variable, the organic precursor was MPEGA480, the silicon nanoparticles were all selected as 2wt% Si nanoparticles with a particle size of 30nm, and the lithium salt was LiTFSI with a total mass ratio of 25%. The preparation and testing methods were the same as in Example 1, as shown in Table 3 below:

[0111] Table 3

[0112]

[0113] Additionally, the XRD analysis of the flexible solid electrolyte in Example 14 is attached. Figure 1 As shown (where glass is glass, polymer is polymer, and intensity is strength), the LSV test curve is attached. Figure 2 As shown in the attached figure (where the horizontal axis represents voltage and the vertical axis represents current), the thermogravimetric analysis curves are as follows. Figure 3 As shown in the attached diagram (where the horizontal axis represents temperature, the left vertical axis represents weight loss, and the right vertical axis represents heat flux), the elastic tensile test graph is as follows. Figure 4 As shown (where A is the original state and B is the stretched state).

[0114] As shown in Table 3 above, the addition of ion-conducting nanoparticles to the flexible solid electrolyte further improved its flexibility, elasticity, and room-temperature ionic conductivity, achieving a room-temperature ionic conductivity of 4.5 × 10⁻⁶. -4 The decomposition rate was increased by 100 S / cm, and the decomposition temperature was further improved, with the decomposition voltage exceeding 7V.

[0115] Examples 18-20

[0116] Using Li salt as the control variable, its preparation and testing methods are the same as in Example 1, as detailed in Table 4 below:

[0117] Table 4

[0118]

[0119] As can be seen from the test results in Table 4 above, different types of alkali metal salts will affect the room temperature ionic conductivity of flexible solid-state batteries, but will have little effect on the flexibility, elasticity and decomposition temperature of the electrolyte.

[0120] Examples 21-28

[0121] A lithium-ion battery, wherein,

[0122] (1) Positive electrode: LiFePO4 and Li(CoNiMn) respectively 1 / 3 The electrode sheet with O2 or other active materials is the positive electrode.

[0123] (2) Negative electrode: lithium foil, artificial graphite, and Li4Ti5O were used respectively. 12 Aluminum foil, etc., are used as negative electrodes.

[0124] (3) Electrolyte: The flexible solid electrolytes of Examples 9 and 14 above are used as electrolytes.

[0125] (4) Assembly of lithium-ion batteries: In an argon-filled glove box, the above-mentioned positive electrode, negative electrode, and electrolyte were assembled into a polymer battery, and the battery cycle performance was tested. The specific materials and cycle stability test results of each embodiment are shown in Table 5 below:

[0126] Table 5

[0127]

[0128] As shown in Table 5 above, the lithium-ion batteries prepared with the flexible solid-state electrolytes of Examples 9 and 14 of this application both retain a capacity of over 92% after 50 cycles of charge and discharge. Among them, the lithium-ion battery prepared with the flexible solid-state electrolyte of Example 14, which simultaneously incorporates semiconductor nanoparticles and ion-conducting nanoparticles, exhibits even better capacity retention, reaching over 95%.

[0129] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a flexible solid electrolyte, characterized in that, Includes the following steps: After mixing polymer monomers, alkali metal salts, and polymer initiators, semiconductor nanoparticles and ion conductor nanoparticles are added and mixed for 4-6 hours under dispersion conditions of pH 5-8 and rotation speed of 800-1600 r / min to obtain a precursor slurry. The polymer monomers include monomers containing polar groups and single-ended unsaturated bonds. The semiconductor nanoparticles include at least one of Si, Ge, Se, GaAs, GaP, AlAs, lnSb, InN, and InP. The mass ratio of the semiconductor nanoparticles to the polymer monomers is (1-10):(90-99). The ion conductor nanoparticles have at least one dimension with a size of 50-200 nm and construct fast ion transport channels through surface and bulk phase. The polar groups are selected from at least one of -O-, =O, -S-, -N-, -P-, C=O, and C≡N. The ion conductor nanoparticles include Fe3O4, LLZO, LLZTO, LGPS, and Na3Zr2Si2PO4. 12 At least one of them; The precursor slurry is polymerized to obtain a molded flexible solid electrolyte. The polymerization process includes: injecting the precursor slurry into a mold containing a flexible skeleton, and initiating a polymerization reaction in the precursor slurry. The polymer monomers are interconnected by addition polymerization through single-ended unsaturated bonds to form a long-chain comb-shaped polymer with a linear carbon chain formed by addition polymerization of unsaturated bonds as the main chain and monomers containing polar groups as branches. The flexible skeleton includes at least one of woven fabric, non-woven fabric, and three-dimensional porous rubber. The porosity of the flexible skeleton is 50% to 90%. The tensile breaking rate of the flexible skeleton in at least one two-dimensional direction is 100% to 400%.

2. The method for preparing the flexible solid electrolyte as described in claim 1, characterized in that, The polymer monomer is selected from at least one of the following: polyethylene glycol monomers, acrylate monomers, acrylate monomers, nitrile monomers, sulfonic acid monomers, and urethane monomers; And / or, the mass-average molecular weight of the polymer monomer is 360~5000.

3. The method for preparing the flexible solid electrolyte as described in claim 2, characterized in that, The semiconductor nanoparticles have at least one dimension with a size of 10~200 nm; And / or, the polymer monomer is selected from at least one of: polyethylene glycol methyl ether methacrylate, methoxy polyethylene glycol acrylate, acrylic acid, methyl acrylate, acrylonitrile, sodium propylene sulfonate, and acrylamide.

4. The method for preparing the flexible solid electrolyte as described in claim 3, characterized in that, The mass ratio of the ion conductor nanoparticles to the polymer monomer is (2~20):(80~98). And / or, the alkali metal salt includes: Li + Na + K + Ca 2+ Mg 2+ Zn 2+ Al 3+ At least one metal cation in the group, and at least one anion selected from hexafluorophosphate, halide anion, bis(trifluorosulfonyl)imide, bis(fluorosulfonyl)imide, oxalate, tetrafluoroborate, dioxaloborate, and perchlorate. And / or, the molar ratio of the metal cation in the alkali metal salt to the polar group in the polymer monomer is 1:(8~40).

5. The method for preparing the flexible solid electrolyte as described in claim 4, characterized in that, The polymer initiator is selected from: photoinitiators; the conditions for initiating the polymerization reaction of the precursor slurry include: irradiation treatment at a light wavelength of 400~760nm for 5~30 minutes; Alternatively, the polymer initiator is selected from: thermal initiators; the conditions for initiating the polymerization reaction of the precursor slurry include: heating at a temperature of 50~200℃ for 10~120 minutes; And / or, the molar ratio of the initiator to the unsaturated bonds in the polymer monomer is (1~5):(95~99).

6. The method for preparing the flexible solid electrolyte as described in claim 5, characterized in that, The photoinitiator is selected from at least one of the following: 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, methyl benzoylcarbamate, and methyl benzoylcarbamate. And / or, the thermal initiator is selected from at least one of the following: benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl peroxide, tert-butyl valerate peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxide, dicyclohexyl peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisoheptanenitrile, and a free radical initiator system in the form of a mixture; wherein, the free radical initiator system in the form of a mixture includes benzoyl peroxide / sucrose, tert-butyl... At least one of the following: tert-butyl hydroperoxide / sodium sodium metabisulfite, benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, potassium persulfate / sodium bisulfite, hydrogen peroxide / tartaric acid, hydrogen peroxide / sodium formaldehyde sulfoxylate, ammonium persulfate / ferrous sulfate, hydrogen peroxide / ferrous sulfate, benzoyl peroxide / N,N-diethylaniline, benzoyl peroxide / ferrous pyrophosphate, potassium persulfate / silver nitrate, persulfate / thiol, cumene hydroperoxide / ferrous chloride, potassium persulfate / ferrous chloride, hydrogen peroxide / ferrous chloride, cumene hydroperoxide / tetraethyleneimine; And / or, the conditions for drying the precursor slurry after polymerization include: drying for 6 to 48 hours under vacuum conditions at a temperature of 50 to 200°C.

7. A flexible solid electrolyte prepared by the method according to any one of claims 1 to 6, characterized in that, The flexible solid electrolyte comprises a polymer matrix and semiconductor nanoparticles, ion conductor nanoparticles, and alkali metal ions incorporated in the polymer matrix.

8. A secondary battery, characterized in that, The secondary battery includes a flexible solid electrolyte prepared by the method described in any one of claims 1 to 6, or a flexible solid electrolyte as described in claim 7.

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