Sulfur-containing piperidine copolymer as well as preparation method and application thereof

Abstract

The invention relates to a sulfur-containing piperidine copolymer as well as a preparation method and application thereof. The structure of the sulfur-containing piperidine copolymer is shown as a formula (I), wherein 0 < x < 1; n > = 1, and n is an integer; ar is a structure containing an aromatic ring; r1 is as shown in the specification; the intrinsic viscosity of the sulfur-containing piperidine copolymer is 1 to 4 dL / g. According to the invention, a specific sulfur-containing structure and an ether-containing chain segment are respectively introduced into the main chain and the side chain of the sulfur-containing piperidine copolymer, so that the sulfur-containing piperidine copolymer not only can form a film well after being mixed with lithium salt, but also can enable a solid electrolyte film prepared from the sulfur-containing piperidine copolymer to have excellent ionic conductivity and cycle retention rate under the conditions of room temperature and high temperature. In addition, the solid electrolyte membrane prepared from the sulfur-containing piperidine copolymer has low electrochemical impedance, wide chemical oxidation window, excellent lithium ion transference number, coulombic efficiency and specific capacity.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery technology, and in particular to a sulfur-containing piperidine copolymer, its preparation method and application. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles and energy storage due to their high energy density and rapid charging and discharging capabilities. Traditional liquid electrolytes pose risks such as flammability, explosiveness, and leakage, leading to a series of safety issues. Solid-state electrolytes, with their wide operating temperature range, effectively address these safety concerns. Polymer solid-state electrolytes typically consist of polymers and lithium salts. Lithium ions are conducted by coordinating with functional groups containing lone pairs of electrons on the polymer chains, utilizing the stretching vibrations and ion transitions of the polymer chain segments. However, at room temperature, the chain movement in polymer solid-state electrolytes is relatively slow, resulting in low ionic conductivity.

[0003] In addition, existing solid electrolytes are insufficient in suppressing lithium dendrites, resulting in poor cycle retention of lithium-ion batteries.

[0004] A Chinese patent describes a polysulfate-based solid polymer electrolyte and its application in lithium batteries. The polymer electrolyte is prepared from polysulfate and lithium salt, but the ionic conductivity of the solid electrolyte membrane made from it still needs to be improved.

[0005] Therefore, there is an urgent need to find a solid electrolyte with high ionic conductivity and cycle retention to meet the rapid development of lithium-ion batteries. Summary of the Invention

[0006] The primary objective of this invention is to overcome the problems of insufficient ionic conductivity and poor cycle retention in existing solid electrolytes, and to provide a sulfur-containing piperidine copolymer. This invention introduces specific sulfur-containing structures and ether-containing segments into the main chain and side chains of the sulfur-containing piperidine copolymer, respectively. This not only allows for good film formation when mixed with lithium salts, but also enables the solid electrolyte membrane made from the sulfur-containing piperidine copolymer to exhibit excellent ionic conductivity and cycle retention under both room temperature and high temperature conditions.

[0007] A further object of the present invention is to provide a method for preparing a sulfur-containing piperidine copolymer.

[0008] Another object of the present invention is to provide the application of sulfur-containing piperidine copolymers in the preparation of solid electrolyte membranes.

[0009] Another object of the present invention is to provide a solid electrolyte membrane.

[0010] Another object of the present invention is to provide a method for preparing a solid electrolyte membrane.

[0011] The above-mentioned objective of this invention is achieved through the following technical solution: A sulfur-containing piperidine copolymer, the structure of which is shown in formula (I):

[0012] Equation (I); Where 0 < x < 1; n ≥ 1, n is an integer; Ar is a structure containing an aromatic ring; R1 is the following structure: The intrinsic viscosity of the sulfur-containing piperidine copolymer is 1~4 dL / g.

[0013] In this invention, the intrinsic viscosity of the sulfur-containing piperidine copolymer was measured by an Ubbelohde viscometer at 30°C.

[0014] It should be understood that x in formula (Ⅰ) of the present invention refers to the ratio of the amount of substance of R1 to the sum of the amounts of substance of R1 and Ar.

[0015] The inventors of this invention have discovered that by introducing specific sulfur-containing structures and ether-containing segments into the main chain and side chain of a sulfur-containing piperidine copolymer, it not only allows for good film formation when mixed with lithium salts, but also enables the solid electrolyte membrane made from the sulfur-containing piperidine copolymer to exhibit excellent ionic conductivity and cycle retention under both room temperature and high temperature conditions. Furthermore, the solid electrolyte membrane made from the sulfur-containing piperidine copolymer of this invention exhibits low electrochemical impedance, a wide chemical oxidation window, excellent lithium-ion transference number, coulombic efficiency, and specific capacity.

[0016] The reasons are twofold: First, lithium ions can be conducted via stretching vibrations and ionic transitions of the ether-containing segments with side branches, resulting in high room-temperature and high-temperature ionic conductivity in solid electrolyte membranes made from sulfur-containing piperidine copolymers. Second, the specific sulfur-containing structure not only effectively separates the cations and anions in the lithium salt, increasing the concentration of freely moving lithium ions in the system, but also widens ion channels and enhances segment mobility, thereby improving ionic conductivity. Furthermore, sulfur-containing piperidine copolymers with specific sulfur-containing structures exhibit excellent interfacial compatibility between the electrolyte and the electrode, effectively suppressing interfacial side reactions and resulting in excellent cycle retention of the solid electrolyte membrane.

[0017] Preferably, Ar has any of the following structures: , , or .

[0018] Preferably, 0.1 ≤ x ≤ 0.4.

[0019] More preferably, 0.2≤x≤0.4.

[0020] More preferably, 0.3 ≤ x ≤ 0.4. When x is controlled within this range, the solid electrolyte membrane made of sulfur-containing piperidine copolymer has higher ionic conductivity, lower electrochemical impedance, and higher cycle retention under both room temperature and high temperature conditions.

[0021] Preferably, 3 ≤ n ≤ 6.

[0022] A method for preparing a sulfur-containing piperidine copolymer includes the following steps: S1. An aromatic ring monomer, a sulfur-containing compound, and N-methyl-4-piperidinone are mixed and then subjected to Friedel-Crafts reaction polycondensation to obtain a terpolymer; S2. The quaternization reaction of the ether-containing haloalkane and the terpolymer yields the sulfur-containing piperidine copolymer; The sulfur-containing compound is dibenzothiophene.

[0023] Preferably, the aromatic ring monomer is at least one of biphenyl, para-terphenyl, meta-terphenyl, or para-tetraphenyl.

[0024] Preferably, in step S1, the ratio of the sum of the amounts of the aromatic ring monomer and the sulfur-containing compound to the amount of N-methyl-4-piperidinone is 1:(1.0~1.5).

[0025] Preferably, in step S1, a solvent is added during the mixing process; the solvent includes, but is not limited to, dichloromethane.

[0026] Preferably, in step S1, the mixing temperature is -10~0℃.

[0027] Preferably, in step S1, the Friedel-Crafts reaction process is as follows: stirring is performed at a first temperature in the presence of an organic strong acid catalyst, followed by heating to a second temperature and stirring.

[0028] More preferably, the first temperature is 0~10℃; the second temperature is 25~30℃.

[0029] More preferably, the stirring time at the first temperature is 1-3 hours; and the stirring time at the second temperature is 5-48 hours. More preferably, the organic strong acid catalyst comprises trifluoroacetic acid and trifluoromethanesulfonic acid in a molar ratio of 1:(0.5~20).

[0030] More preferably, the molar ratio of the aromatic ring monomer to the organic strong acid catalyst is 1:(1~60).

[0031] Preferably, in step S2, the quaternization reaction takes 24 to 48 hours.

[0032] Preferably, in step S2, the temperature of the quaternization reaction is 70~90℃.

[0033] Preferably, in step S2, the mass ratio of the terpolymer to the halogenated hydrocarbon containing the ether segment is 1:(0.9~1.2).

[0034] In this invention, the halogenated hydrocarbons containing ether segments can be commercially available or self-made. Self-made hydrocarbons can refer to existing technologies.

[0035] Preferably, in step S2, the halogenated hydrocarbon containing the ether segment is at least one of diethylene glycol 2-chloroethyl methyl ether, triethylene glycol 2-chloroethyl methyl ether, tetraethylene glycol 2-chloroethyl methyl ether, pentaethylene glycol 2-chloroethyl methyl ether, diethylene glycol 2-bromoethyl methyl ether, triethylene glycol 2-bromoethyl methyl ether, tetraethylene glycol 2-bromoethyl methyl ether, or pentaethylene glycol 2-bromoethyl methyl ether.

[0036] The present invention also protects the use of the above-mentioned sulfur-containing piperidine copolymer in the preparation of solid electrolyte membranes.

[0037] Preferably, the solid electrolyte membrane is a solid electrolyte membrane of a lithium-ion battery.

[0038] A solid electrolyte membrane comprises the following components in parts by weight: 30-80 parts of the above-mentioned sulfur-containing piperidine copolymer, 10-40 parts of lithium salt, and 5-30 parts of plasticizer.

[0039] Preferably, the solid electrolyte membrane is a solid electrolyte membrane of a lithium-ion battery.

[0040] Preferably, the solid electrolyte membrane comprises the following components in parts by weight: 30-50 parts of the above-mentioned sulfur-containing piperidine copolymer, 10-40 parts of lithium salt, and 10-30 parts of plasticizer.

[0041] Preferably, the lithium salt is at least one selected from lithium carbonate, lithium perchlorate, lithium hexafluorophosphate, lithium difluorophosphate, lithium bis(oxalate)borate, lithium difluorooxalateborate, lithium tetrafluoroborate, lithium bis(malonate)borate, lithium malonate oxalateborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethane)sulfonylimide, lithium bis(trifluoromethane)sulfonylmethyl, or lithium 4,5-dicyano-2-trifluoromethylimidazolium.

[0042] Preferably, the plasticizer is at least one selected from succinic anhydride, polyvinyl alcohol, ethylene nitrile, fluoroacetonitrile, ethylene carbonate, propylene carbonate, polyethylene glycol, γ-butyrolactone, triethyl phosphate, dimethyl carbonate, or diethyl carbonate or fluoroethylene carbonate.

[0043] Preferably, the thickness of the solid electrolyte membrane is 45~55 μm.

[0044] A method for preparing a solid electrolyte membrane includes the following steps: mixing the above-mentioned sulfur-containing piperidine copolymer, lithium salt and plasticizer to obtain an electrolyte solution, casting, and drying to obtain the solid electrolyte membrane.

[0045] Preferably, a solvent is also added during the mixing process.

[0046] More preferably, the solvent is at least one of N-methylpyrrolidone, N-dimethylacetamide, or N-dimethylformamide.

[0047] Compared with the prior art, the beneficial effects of the present invention are: This invention introduces specific sulfur-containing structures and ether-containing segments into the main chain and side chain of a sulfur-containing piperidine copolymer, respectively. This not only allows for good film formation when mixed with lithium salts, but also enables the solid electrolyte membrane made from the sulfur-containing piperidine copolymer to exhibit excellent ionic conductivity and cycle retention under both room temperature and high temperature conditions. Furthermore, the solid electrolyte membrane made from the sulfur-containing piperidine copolymer of this invention exhibits low electrochemical impedance, a wide chemical oxidation window, excellent lithium-ion transference number, coulombic efficiency, and specific capacity. Attached Figure Description

[0048] Figure 1 The NMR spectrum of the sulfur-containing piperidine copolymer of Example 1; Figure 2 The NMR spectrum of the sulfur-containing piperidine copolymer of Example 2; Figure 3 The NMR spectrum of the sulfur-containing piperidine copolymer of Example 3; Figure 4 The NMR spectrum of the sulfur-containing piperidine copolymer of Example 4; Figure 5 The NMR spectrum of the control copolymer of Comparative Example 3 is shown. Figure 6 This is a chemical oxidation window diagram of the battery made from the solid electrolyte membrane of Example 3; Figure 7 This is a graph showing the lithium-ion migration rate of the battery made from the solid electrolyte membrane of Example 3. Detailed Implementation

[0049] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0050] Example 1 This embodiment provides a sulfur-containing piperidine copolymer and a solid electrolyte membrane prepared therefrom, the preparation method of which includes the following steps: (1) 18 mmol of terphenyl, 2 mmol of sulfur-containing compound, 22 mmol of N-methyl-4-piperidinone and 25 mL of dichloromethane were added to a flask and stirred at 0 °C for 3 h. Then trifluoroacetic acid (336.6 mmol) and trifluoromethanesulfonic acid (282.7 mmol) were added and stirred at 0 °C for 3 h. Then the mixture was stirred at 25 °C for 24 h. The solid was obtained by sedimentation in water. The solid was washed with ethanol and dried to obtain a terpolymer. The sulfur-containing compound was dibenzothiophene (CAS No.: 132-65-0).

[0051] (2) Dissolve the terpolymer from step (1) in dimethyl sulfoxide, add the halogenated hydrocarbon containing the ether segment, and react at 80°C in the dark for 48 h. After the reaction is completed, pour the reaction solution into ethyl acetate to precipitate a white solid. Wash the white solid with deionized water and dry it in an oven at 80°C to obtain the sulfur-containing piperidine copolymer. The halogenated hydrocarbon containing the ether segment is diethylene glycol 2-bromoethyl methyl ether, and the mass ratio of the terpolymer to the halogenated hydrocarbon containing the ether segment is 1:0.9.

[0052] (3) By weight, 30 parts of the sulfur-containing piperidine copolymer from step (2), 40 parts of the lithium salt, and 30 parts of the plasticizer are added to N-methylpyrrolidone and mixed evenly to obtain an electrolyte solution. The electrolyte solution is then poured into a mold and kept at 60 °C for 48 h to obtain a solid electrolyte membrane with a thickness of 50 μm. The lithium salt is lithium bis(trifluoromethanesulfonylimide), and the plasticizer is succinic anionyl nitrile.

[0053] In this embodiment, the sulfur-containing piperidine copolymer obtained in step (2) has an intrinsic viscosity of 2.28 dL / g at 30 °C, as measured by an Ubbelohde viscometer. Its structure is shown below: ; In the structure of the sulfur-containing piperidine copolymer in this embodiment, x is 0.1, n is 3, and R1 has the following structure: The structural formula of Ar is .

[0054] In this embodiment, the sulfur-containing piperidine copolymer obtained in step (2) was subjected to NMR testing, and the results are as follows: Figure 1 As shown. Figure 1 This indicates the successful synthesis of sulfur-containing piperidine copolymers.

[0055] Examples 2-4 Examples 2-4 provide a series of sulfur-containing piperidine copolymers and solid electrolyte membranes prepared therefrom. The preparation methods differ from those in Example 1 in that the amounts of terphenyl and sulfur-containing compounds used in step (1) are shown in Table 1.

[0056] Table 1. Differences between Examples 1-5

[0057] The intrinsic viscosities of the sulfur-containing piperidine copolymers obtained in step (2) of Examples 2-4 at 30°C were measured by Ubbelohde viscometer to be 2.48 dL / g, 2.32 dL / g, and 2.18 dL / g, respectively.

[0058] The difference between the structures of the sulfur-containing piperidine copolymers in Examples 2-4 and those in Example 1 is that the x values ​​in the structures of the sulfur-containing piperidine copolymers in Examples 2-4 are 0.2, 0.3, and 0.4, respectively.

[0059] The sulfur-containing piperidine copolymers obtained in step (2) of Examples 2-4 were subjected to NMR analysis, and the results are as follows: Figures 2-4 As shown. Figures 2-4 This demonstrates the successful synthesis of the sulfur-containing piperidine copolymers in Examples 2-4.

[0060] Example 5 This embodiment provides a sulfur-containing piperidine copolymer and a solid electrolyte membrane prepared therefrom. The preparation method differs from that in Example 1 in that: in step (2), the halogenated hydrocarbon containing the ether segment is pentaethylene glycol 2-chloroethyl methyl ether (structural formula: ).

[0061] In this embodiment, the sulfur-containing piperidine copolymer obtained in step (2) has an intrinsic viscosity of 3.62 dL / g at 30°C as measured by Ubbelohde viscometer.

[0062] The difference between the structure of the sulfur-containing piperidine copolymer in this embodiment and that in Example 1 is that n is 6 in the structure of the sulfur-containing piperidine copolymer in this embodiment.

[0063] Example 6 This embodiment provides a sulfur-containing piperidine copolymer and a solid electrolyte membrane prepared therefrom. The preparation method differs from that in Example 1 in that the weight parts of the sulfur-containing piperidine copolymer, lithium salt and plasticizer in the solid electrolyte membrane are shown in Table 2.

[0064] Table 2. Differences between Example 1 and Example 6 (Unit: parts by weight)

[0065] Comparative Example 1 This comparative example provides a comparative copolymer and a comparative solid electrolyte membrane prepared therefrom. The preparation method differs from that of Example 3 in that: in step (1), the sulfur-containing compound is replaced with an oxygen-containing compound, the oxygen-containing compound being dibenzofuran (CAS No.: 132-64-9), and polymer 1# is finally obtained; in step (2), the terpolymer is replaced with polymer 1# obtained in step (1), and comparative copolymer 1# is finally obtained; in step (3), the sulfur-containing piperidine copolymer is replaced with comparative copolymer 1#, and comparative solid electrolyte membrane is finally obtained.

[0066] In this comparative example, the intrinsic viscosity of the control copolymer 1# obtained in step (2) at 30°C was measured to be 2.43 dL / g using an Ubbelohde viscometer, and its structure is shown below: .

[0067] Comparative Example 2 This comparative example provides a comparative copolymer and a comparative solid electrolyte membrane prepared therefrom. The preparation method of the comparative copolymer differs from that of Example 1 in that step (2) is not performed; in step (3), the sulfur-containing piperidine copolymer is replaced with the ternary copolymer of step (1), and the comparative solid electrolyte membrane is finally obtained.

[0068] Comparative Examples 3-4 This comparative example provides a series of comparative copolymers. The preparation method of the comparative copolymers differs from the preparation method of the sulfur-containing piperidine copolymer in Example 1 in that the sulfur-containing compound in step (1) is shown in Table 3.

[0069] Table 3. Differences between Example 1 and Comparative Examples 3-4

[0070] The intrinsic viscosities of the comparative copolymers of Comparative Examples 3 and 4 were measured by Ubbelohde viscometer at 30°C and were 2.20 dL / g and 2.22 dL / g, respectively.

[0071] The structure of the comparative copolymer of Comparative Example 3 differs from that of the sulfur-containing piperidine copolymer of Example 1 in that R1 in the comparative copolymer of Comparative Example 3 has the following structure: The difference between the structure of the comparative copolymer of Comparative Example 4 and that of Example 1 is as follows: In the structure of the comparative copolymer of Comparative Example 4, R1 has the following structure: .

[0072] The comparative copolymer of Comparative Example 3 was subjected to NMR testing, and the results are as follows: Figure 5 As shown. Figure 5 This demonstrates the successful synthesis of the comparative copolymer of Comparative Example 3.

[0073] By weight, 30 parts of the comparative copolymers of Comparative Examples 3 and 4 were mixed with 40 parts of bis(trifluoromethanesulfonylmethyl)lithium and 30 parts of succinate in N-methylpyrrolidone to obtain an electrolyte solution. The electrolyte solution was then poured into a mold and kept at 60°C for 48 h to obtain a comparative solid electrolyte membrane. However, due to the poor film-forming properties of the comparative copolymers prepared from the sulfur-containing compounds of Comparative Examples 3 and 4 after mixing with lithium salt, they could not be made into solid electrolytes for subsequent performance testing.

[0074] Performance testing (1) Electrochemical performance testing The solid electrolyte membranes of each embodiment and the comparative solid electrolyte membrane of the comparative example were assembled into batteries for electrochemical performance testing. The results are shown in Table 4 and 5. Figures 6-7 The assembly method is as follows: The solid electrolyte membranes of each embodiment or the comparative solid electrolyte membrane of the comparative example are cut into circular electrolyte membrane pieces with a diameter of 16 mm. 5 μL of a 1 mol / L LiPF6 solution (solvents being diethyl carbonate, ethyl methyl carbonate, and ethylene carbonate in equal volume ratios) is dropped onto both sides of the electrolyte membrane piece. Then, it is assembled with the positive and negative electrodes to form a 2032 button battery. The positive electrode material is lithium nickel cobalt manganese oxide (NCM811), and the negative electrode material is lithium metal. It should be understood that the room temperature ionic conductivity and 60°C (high temperature) ionic conductivity data in Table 4 are expressed in scientific notation. For example, "1.66E-04" specifically means: 1.66 × 10⁻⁴. -4 .

[0075] in, Figures 6-7 The figures show the electrochemical oxidation window number and lithium-ion migration number of the battery fabricated using the solid electrolyte membrane in Example 3, respectively. Figures 6-7 As can be seen, the battery made from the solid electrolyte membrane of Example 3 has an electrochemical oxidation window of 5.5V and a lithium-ion transference number of 0.68. The battery made from the solid electrolyte membrane of Example 3 has an initial coulombic efficiency of 80%, an initial charge specific capacity of 190 mAh / g, and an initial discharge specific capacity of 152 mAh / g. The test results for the electrochemical oxidation window, lithium-ion transference number, initial coulombic efficiency, initial charge specific capacity, and initial discharge specific capacity of other examples are similar to those of Example 3, indicating that the solid electrolyte membrane made from the sulfur-containing piperidine copolymer of the present invention has a wide chemical oxidation window, excellent lithium-ion transference number, coulombic efficiency, and specific capacity.

[0076] Table 4. Test results of electrochemical performance

[0077] As shown in Table 4, the solid electrolyte membranes prepared from the sulfur-containing piperidine copolymers in Examples 1-6 exhibit electrochemical impedances below 350 Ω, room-temperature ionic conductivity of 1.42E-04 S / cm or higher, high-temperature ionic conductivity of 3.16E-04 S / cm or higher, and discharge specific capacity retention of 88% or higher after 150 cycles. In Examples 1-4, as the concentration of x in the sulfur-containing piperidine copolymer gradually increases, the room-temperature / high-temperature ionic conductivity initially increases and then decreases. This is because as the sulfur content in the main chain of the sulfur-containing piperidine copolymer increases, the number of sulfur sites that lithium ions can bind increases, which is beneficial for the rapid migration of lithium ions in the electrolyte. However, when the sulfur content in the sulfur-containing piperidine copolymer continues to increase, chain segment entanglement occurs, causing lithium ions to coordinate simultaneously with sulfur atoms on multiple chain segments, which hinders lithium ion migration and thus reduces ionic conductivity.

[0078] The above demonstrates that the solid electrolyte membrane made from the sulfur-containing piperidine copolymer of the present invention has low electrochemical impedance, high room temperature / high temperature ionic conductivity, and excellent cycle retention.

[0079] Comparative Example 1, which replaced sulfur-containing compounds with oxygen-containing compounds, produced a comparative solid electrolyte membrane with high electrochemical impedance, low room temperature / high temperature ionic conductivity, and low cycle retention.

[0080] Comparative Example 2 did not incorporate ether-containing segments, resulting in a solid electrolyte membrane with high electrochemical impedance and low ionic conductivity at room temperature / high temperature. This is because lithium ions cannot be conducted through stretching vibrations and ionic transitions of ether-containing segments, leading to low ionic conductivity.

[0081] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A sulfur-containing piperidine copolymer, characterized in that, The structure of the sulfur-containing piperidine copolymer is shown in formula (I): Equation (I); Where 0 < x < 1; n ≥ 1, n is an integer; Ar is a structure containing an aromatic ring; R1 is the following structure: The intrinsic viscosity of the sulfur-containing piperidine copolymer is 1~4 dL / g.

2. The sulfur-containing piperidine copolymer as described in claim 1, characterized in that, The Ar can be any of the following structures: , , or .

3. The sulfur-containing piperidine copolymer as described in claim 1, characterized in that, 0.1≤x≤0.4。 4. The sulfur-containing piperidine copolymer as described in claim 1, characterized in that, 0.2≤x≤0.4。 5. The sulfur-containing piperidine copolymer as described in claim 1, characterized in that, 3≤n≤6。 6. The method for preparing the sulfur-containing piperidine copolymer according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. An aromatic ring monomer, a sulfur-containing compound and N-methyl-4-piperidinone are mixed and then subjected to Friedel-Crafts reaction polycondensation to obtain a terpolymer; S2. The quaternization reaction of the ether-containing haloalkane and the terpolymer yields the sulfur-containing piperidine copolymer. The sulfur-containing compound is dibenzothiophene.

7. The preparation method according to claim 6, characterized in that, In step S1, the ratio of the sum of the amounts of the aromatic ring monomer and the sulfur-containing compound to the amount of N-methyl-4-piperidinone is 1:(1.0~1.5).

8. The use of the sulfur-containing piperidine copolymer according to any one of claims 1 to 5 in the preparation of solid electrolyte membranes.

9. A solid electrolyte membrane, characterized in that, It comprises the following components in parts by weight: 30-80 parts of the sulfur-containing piperidine copolymer as described in any one of claims 1-5, 10-40 parts of lithium salt, and 5-30 parts of plasticizer.

10. The method for preparing the solid electrolyte membrane according to claim 9, characterized in that, The process includes the following steps: mixing the sulfur-containing piperidine copolymer, lithium salt, and plasticizer according to any one of claims 1 to 5 to obtain an electrolyte solution, casting, and drying to obtain the solid electrolyte membrane.

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