PEO-based solid-state electrolyte, preparation thereof and application of PEO-based solid-state electrolyte in solid-state lithium-sulfur battery

Abstract

The invention relates to the technical field of lithium-sulfur batteries, and discloses a PEO-based solid electrolyte preparation method, which comprises: carrying out a copolymerization reaction on a PEO polymer, silane and a reaction auxiliary agent to prepare a silane cross-linked modified PEO matrix; the method comprises the following steps: adding Li PF6 into a lithium salt polymer of Li (CF3SO2) 2N to prepare a conductive ion source of a [Li (CF3SO2) 2N-10% Li PF6] double lithium salt system; the preparation method comprises the following steps: dissolving a modified PEO matrix and a [Li (CF3SO2) 2N-10% Li PF6] lithium salt polymer in an acetone solvent, and adding an inorganic nano filler; and carrying out primary drying in a sample mold, and then carrying out hot-pressing cooling to obtain the PEO-based solid electrolyte. According to the PEO-based solid electrolyte, the preparation thereof and the application of the PEO-based solid electrolyte in a solid-state lithium-sulfur battery, polymer crystallization is inhibited through PEO matrix modified copolymerization, the movement ability of a polymer chain segment is improved, so that the room-temperature conductivity of the electrolyte is improved, the conductivity under a low-temperature condition can be improved by preparing a [Li (CF3SO2) 2N-10% Li PF6] double-lithium salt system, and the inorganic nano filler component is added, so that the performance of the electrolyte is improved. And the electrolyte performance is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-sulfur batteries, and in particular to a PEO-based solid electrolyte and its preparation and application in solid-state lithium-sulfur batteries. Background Art

[0002] PEO-based solid electrolytes, namely polyoxyethylene polymer solid electrolytes, show great potential in solid-state lithium-sulfur ion batteries due to their excellent mechanical flexibility, good interfacial contact and good flexibility in component design. At the same time, PEO-based solid electrolytes have significant advantages in improving electrode interface compatibility and are one of the most promising electrolyte materials currently.

[0003] After searching, according to the invention patent with Chinese patent publication number CN118136940A, a PEO-based solid electrolyte and a preparation method thereof are disclosed. The preparation method of the PEO-based solid electrolyte uses PEO as a matrix, Li TFS I as a lithium salt, and acetonitrile as a solvent, and then the mixture is stirred and mixed and vacuum dried, and then dried in a polytetrafluoroethylene mold to obtain a solid electrolyte;

[0004] However, after the conventional PEO matrix and lithium salt material are composited, there are still a large number of crystalline areas, which leads to too low room temperature conductivity. At the same time, the small number of internal lithium ion migration limits the charging and discharging efficiency of the battery, affecting the battery's cycle performance and safety performance. Therefore, the effect of improving the electrolyte performance through material selection and preparation of the PEO-based solid electrolyte needs to be further improved. Therefore, a PEO-based solid electrolyte and its preparation and application in solid-state lithium-sulfur batteries are proposed. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the shortcomings of the prior art, the present invention provides a PEO-based solid electrolyte and its preparation and application in a solid-state lithium-sulfur battery, which has the advantages of modifying the PEO matrix and adopting a double lithium salt system to improve the electrolyte performance, and solves the problem that the PEO-based solid electrolyte and its preparation method in the above-mentioned background technology adopt a conventional PEO matrix and a lithium salt material to composite, which cannot effectively improve the room temperature conductivity and battery charge and discharge performance.

[0007] (II) Technical solution

[0008] In order to achieve the above-mentioned purpose of modifying the PEO matrix and using a dual lithium salt system to improve the electrolyte performance, the present invention provides the following technical solution: a PEO-based solid electrolyte, including a modified PEO matrix, a lithium salt, and an inorganic nanofiller as raw materials for preparing the solid electrolyte.

[0009] Another technical problem to be solved by the present invention is to provide a method for preparing a PEO-based solid electrolyte, comprising the following steps:

[0010] S1. Adding an appropriate amount of PEO polymer, silane and a reaction aid into a high pressure reactor, copolymerization reaction occurs at a certain temperature and pressure to prepare a silane cross-linked modified PEO matrix;

[0011] S2. In Li(CF 3 SO 2 ) 2 Adding LiPF to the lithium salt polymer of N 6 , to obtain [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ] Conductive ion source for double lithium salt system;

[0012] S3. Use sufficient acetone as solvent base, select appropriate amount of modified PEO matrix and [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ] The lithium salt polymer is dissolved in an acetone solvent and stirred uniformly at a certain temperature to obtain a mixed solution;

[0013] S4. Adding an inorganic nanofiller to the mixed solution, stirring and dissolving the mixture at a certain temperature to obtain an electrolyte solution;

[0014] S5. Pour the prepared electrolyte solution into the sample mold for preliminary drying, then place the sample mold into a hot press, perform hot pressing operation at a certain hot pressing temperature and hot pressing pressure, and demold and remove after cooling to room temperature to obtain the prepared PEO-based solid electrolyte.

[0015] Preferably, in step S1, the reaction aid includes a reaction solvent, an initiator and a molecular weight regulator, the reaction solvent is selected from one of toluene, n-hexane or dichloromethane, and is used to dissolve the silane monomer and the PEO polymer, the initiator is selected from one of benzoyl peroxide and diisopropylbenzene peroxide, and the initiator dosage range is set to 0.5%-0.8% of the mass of the PEO polymer and the silane, and the molecular weight regulator is selected from one of propane, propylene or propionaldehyde.

[0016] Preferably, in step S1, the PEO polymer, silane and reaction solvent are added to an ultrasonic agitator, and ultrasonically stirred for 10 min at 25° C., the ultrasonic frequency of the ultrasonic agitator is 20KHz-60KHz, and the stirring speed is 250-1200rpm to obtain a mixture A, and the obtained mixture A is added to a high-pressure reactor, and the reaction temperature is set to 80° C.-90° C. and the reaction pressure is set to 6-10MPa. The specific steps of the copolymerization reaction include:

[0017] a. Add the mixture A in which the PEO polymer, silane and the reaction solvent are fully dissolved into a high-pressure reactor, and carry out a prepolymerization reaction at a reaction temperature of 80°C and a reaction pressure of 6.5MPa to generate a preliminary copolymer or active intermediate;

[0018] b. Then, a continuous polymerization reaction was carried out at a reaction temperature of 85°C and a reaction pressure of 10 MPa, and various parameters such as temperature and pressure during the reaction were monitored in real time;

[0019] c. After the reaction rate gradually decreases to a stable state, stop heating and slowly release the pressure, discharge the reaction product and successively filter, distill, wash and dry to obtain a silane-crosslinked modified PEO matrix.

[0020] Preferably, in step S2, the [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 The specific steps of the double lithium salt system conductive ion source include:

[0021] a. Select CF 3 SO 2 NH 2 and strong alkaline lithium salt LiOH as reaction raw materials, added into the reactor for preliminary reaction to generate the intermediate product CF 3 SO 2 NHLi, then add quantitative CF 3 SO 2 C l for further reaction;

[0022] b. Adding a quantitative lithium salt catalyst LiF at the same time, stirring at a temperature of -15 ℃ ~ 25 ℃, stirring at a speed of 200-500rpm to obtain a mixture B;

[0023] c. Recrystallize and dry the mixture B under reduced pressure to obtain Li(CF 3 SO 2 ) 2 N crystal;

[0024] d. Add a certain volume of HF solution to the reactor, select a certain amount of LiF and add the HF solution to continuously pass the PF at a low temperature of -30℃ to -20℃ and normal pressure. 5 gas, reacts to form LiPF 6 The solution is then recrystallized and dried under reduced pressure to obtain LiPF with high purity. 6 Crystals;

[0025] e. Select appropriate amount of Li(CF 3 SO 2 ) 2 N crystal and LiPF 6 The crystals were fully dissolved in the solvent to obtain [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ]Conductive ion source for double lithium salt system.

[0026] Preferably, in step S3, the amount of the acetone solvent is greater than the total amount of the modified PEO matrix, the lithium salt and the inorganic nanofiller, and the modified PEO matrix and [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 The lithium salt polymer is dissolved in acetone solvent and fully dissolved in an ultrasonic stirrer at a stirring temperature of 25°C to 30°C and a stirring speed of 200-1200 rpm to obtain a mixture C.

[0027] Preferably, in step S4, the inorganic nanofiller is selected from TiO 2 、Al 2 O 3 、BaTiO 3 and ZnAl 2 O 4 One or two of the above are added, a quantitative inorganic nanofiller is added to the mixture C, and the mixture is fully stirred and dissolved in an ultrasonic stirrer at a stirring temperature of 25° C. to 35° C. and a stirring speed of 500-1500 rpm to obtain an electrolyte solution.

[0028] Preferably, in step S5, the specific steps of obtaining a PEO-based solid electrolyte according to electrolyte dissolution include:

[0029] a. Pour the electrolyte solution into the sample mold and perform preliminary drying at a temperature of 50°C-60°C to form a solid-slurry preliminary molding state;

[0030] b. Place the sample mold into a hot press and perform hot pressing at a pressure of 10-15 MPa at 70°C-85°C;

[0031] c. After the hot pressing is completed, the mixture is cooled to room temperature and the pressure is slowly released. The solid structure is demolded and taken out to obtain a PEO-based solid electrolyte. The hot-pressed PEO-based solid electrolyte is annealed to improve the ionic conductivity of the electrolyte.

[0032] Application of a PEO-based solid electrolyte obtained by any preparation method in a solid-state lithium-sulfur battery.

[0033] (III) Beneficial effects

[0034] Compared with the prior art, the present invention provides a PEO-based solid electrolyte and its preparation and application in a solid-state lithium-sulfur battery, which has the following beneficial effects:

[0035] 1. The PEO-based solid electrolyte and its preparation and application in solid-state lithium-sulfur batteries are prepared by selecting a PEO polymer and carrying out copolymerization reaction in a high-pressure reactor through silane and a reaction aid. The PEO matrix-modified copolymerization can inhibit polymer crystallization and improve the mobility of polymer chain segments, thereby effectively improving the room temperature conductivity of the electrolyte.

[0036] 2. The PEO-based solid electrolyte and its preparation and application in solid-state lithium-sulfur batteries are prepared by 3 SO 2 ) 2 N-10%LiPF 6 ]The double lithium salt system can improve the conductivity under low temperature conditions, and the addition of inorganic nanofiller components can further improve the conductivity and ion migration number inside the electrolyte, thereby optimizing the battery charge and discharge performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a flow chart of the method for preparing a PEO-based solid electrolyte;

[0038] Figure 2 It is a schematic diagram of the conductivity of different lithium salts of the present invention;

[0039] Figure 3 Schematic diagram of room temperature conductivity of different inorganic fillers of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Embodiment 1:

[0042] S1. Add appropriate amount of PEO polymer, silane and reaction aid into a high-pressure reactor, and copolymerize under a certain temperature and pressure to prepare a silane-crosslinked modified PEO matrix.

[0043] Furthermore, in step S1, the reaction aid comprises a reaction solvent, an initiator and a molecular weight regulator, the reaction solvent is selected from one of toluene, n-hexane or dichloromethane, and is used to dissolve the silane monomer and the PEO polymer, the initiator is selected from one of benzoyl peroxide and dicumyl peroxide, and the initiator dosage range is set to 0.5%-0.8% of the mass of the PEO polymer and the silane, and the molecular weight regulator is selected from one of propane, propylene or propionaldehyde;

[0044] In step S1, the PEO polymer, silane and reaction solvent are added to an ultrasonic stirrer, and ultrasonic stirring is performed for 10 minutes at 25° C. The ultrasonic frequency of the ultrasonic stirrer is 20KHz-60KHz, and the stirring speed is 250-1200rpm to obtain a mixture A. The obtained mixture A is added to a high-pressure reactor, and the reaction temperature is set to 80° C.-90° C. and the reaction pressure is set to 6-10MPa. The specific steps of the copolymerization reaction include:

[0045] a. Add the mixture A in which the PEO polymer, silane and the reaction solvent are fully dissolved into a high-pressure reactor, and carry out a prepolymerization reaction at a reaction temperature of 80°C and a reaction pressure of 6.5MPa to generate a preliminary copolymer or active intermediate;

[0046] b. Then, a continuous polymerization reaction was carried out at a reaction temperature of 85°C and a reaction pressure of 10 MPa, and various parameters such as temperature and pressure during the reaction were monitored in real time;

[0047] c. After the reaction rate gradually decreases to a stable state, stop heating and slowly release the pressure, discharge the reaction product and successively filter, distill, wash and dry to obtain a silane-crosslinked modified PEO matrix.

[0048] Specifically, in this embodiment, PEO polymer and silane are used as reaction monomers, n-hexane is selected as the reaction solvent to dissolve and mix the PEO polymer and silane, and then dicumyl peroxide is selected as the initiator. At this time, the selected initiator dosage range is 0.5%-0.8% of the total mass of the PEO polymer and the silane, which is used to start the copolymerization reaction and adjust the reaction rate;

[0049] First, the PEO polymer and silane are fully stirred and mixed in an ultrasonic stirrer at a temperature of 25°C and a stirring frequency of 20KHz-60KHz. After mixing, the copolymerization reaction is completed with a reaction aid in a high-pressure reactor. The room temperature conductivity of the electrolyte can be improved by copolymerization modification of the PEO matrix, thereby further improving the battery performance.

[0050] Embodiment 2:

[0051] S2. In Li(CF 3 SO 2 ) 2 LiPF 6 , to obtain [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ]Conductive ion source for double lithium salt system.

[0052] Further, in step S2, the [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 The specific steps of the double lithium salt system conductive ion source include:

[0053] a. Select CF 3 SO 2 NH 2 and strong alkaline lithium salt LiOH as reaction raw materials, added into the reactor for preliminary reaction to generate the intermediate product CF 3 SO 2 NHLi, then add quantitative CF 3 SO 2 C l for further reaction;

[0054] b. Adding a quantitative lithium salt catalyst LiF at the same time, stirring at a temperature of -15 ℃ ~ 25 ℃, stirring at a speed of 200-500rpm to obtain a mixture B;

[0055] c. Recrystallize and dry the mixture B under reduced pressure to obtain Li(CF 3 SO 2 ) 2 N crystal;

[0056] d. Add a certain volume of HF solution to the reactor, select a certain amount of LiF and add the HF solution to continuously pass the PF at a low temperature of -30℃ to -20℃ and normal pressure. 5 gas, reacts to form LiPF 6 The solution is then recrystallized and dried under reduced pressure to obtain LiPF with high purity.6 Crystals;

[0057] e. Select appropriate amount of Li(CF 3 SO 2 ) 2 N crystal and LiPF 6 The crystals were fully dissolved in the solvent to obtain [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ]Conductive ion source for double lithium salt system.

[0058] Specifically, in this embodiment, CF 3 SO 2 NH 2 A preliminary reaction with a strong alkaline lithium salt LiOH was performed to obtain CF 3 SO 2 NHLi, then continue to add CF 3 SO 2 C l raised the reaction temperature to 75°C, added lithium salt catalyst LiF, stirred evenly at a speed of 200-500 rpm under a temperature condition of -15°C to 25°C, and obtained Li(CF 3 SO 2 ) 2 N solution, and then recrystallized and dried under reduced pressure to obtain high-purity Li(CF 3 SO 2 ) 2 N crystal;

[0059] Similarly, HF solution was added to the reactor, followed by LiF, and PF was continuously introduced at -30℃ to -20℃ under normal pressure. 5 gas to react to form LiPF 6 Solution, to obtain LiPF 6 The solution was recrystallized and dried under reduced pressure to obtain LiPF with high purity. 6 crystal, and then to Li(CF 3 SO 2 ) 2 N crystal and LiPF 6 The crystals are fully dissolved in organic solvents to form [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ]Conductive ion source for double lithium salt system.

[0060] Embodiment three:

[0061] S5. Pour the prepared electrolyte solution into the sample mold for preliminary drying, then place the sample mold into a hot press, perform hot pressing operation at a certain hot pressing temperature and hot pressing pressure, and demold and remove after cooling to room temperature to obtain the prepared PEO-based solid electrolyte.

[0062] Furthermore, in step S5, the specific steps of obtaining a PEO-based solid electrolyte according to electrolyte dissolution include:

[0063] a. Pour the electrolyte solution into the sample mold and perform preliminary drying at a temperature of 50°C-60°C to form a solid-slurry preliminary molding state;

[0064] b. Place the sample mold into a hot press and perform hot pressing at a pressure of 10-15 MPa at 70°C-85°C;

[0065] c. After the hot pressing is completed, the mixture is cooled to room temperature and the pressure is slowly released. The solid structure is demolded and taken out to obtain a PEO-based solid electrolyte. The hot-pressed PEO-based solid electrolyte is annealed to improve the ionic conductivity of the electrolyte.

[0066] Specifically, in this embodiment, the prepared electrolyte solution is poured into a sample mold, and the sample mold is preliminarily heated and dried at a temperature of 50°C-60°C to form a preliminary solid-liquid mixed molding state, and then the mold is placed in a hot press and hot pressed at 70°C-85°C and a pressure of 10-15MPa to further mold the electrolyte solution;

[0067] After hot pressing, the pressure is slowly released after cooling to room temperature to obtain a PEO-based solid electrolyte, which is then annealed at a temperature lower than the hot pressing temperature, 55°C, for 3 hours, thereby further improving the ionic conductivity of the electrolyte.

[0068] The beneficial effects of the present invention are as follows: the PEO-based solid electrolyte and its preparation and application in a solid-state lithium-sulfur battery, by selecting a PEO polymer, carrying out a copolymerization reaction in a high-pressure reactor through silane and a reaction aid, by modifying the copolymerization of the PEO matrix, the polymer crystallization can be inhibited, the polymer chain segment mobility can be improved, thereby effectively improving the room temperature conductivity of the electrolyte, and by preparing [Li(CF 3 SO 2 ) 2 N-10%LiPF 6 ]The double lithium salt system can improve the conductivity under low temperature conditions, and the addition of inorganic nanofiller components can further improve the conductivity and ion migration number inside the electrolyte, thereby optimizing the battery charge and discharge performance.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A PEO-based solid electrolyte, characterized in that: The method comprises using modified PEO matrix, lithium salt and inorganic nanofiller as raw materials for preparing solid electrolyte.

2. A method for preparing a PEO-based solid electrolyte, characterized in that: The following steps are involved: S1. Adding an appropriate amount of PEO polymer, silane and a reaction aid into a high pressure reactor, copolymerization reaction occurs at a certain temperature and pressure to prepare a silane cross-linked modified PEO matrix; S2. Adding LiPF6 to the lithium salt polymer of Li(CF3SO2)2N to obtain a conductive ion source of the double lithium salt system [Li(CF3SO2)2N-10%LiPF6]; S3. A sufficient amount of acetone is used as a solvent base, and an appropriate amount of modified PEO matrix and [Li(CF3SO2)2N-10%LiPF6] lithium salt polymer are selected and dissolved in the acetone solvent, and stirred uniformly at a certain temperature to obtain a mixed solution; S4. Adding an inorganic nanofiller to the mixed solution, stirring and dissolving the mixture at a certain temperature to obtain an electrolyte solution; S5. Pour the prepared electrolyte solution into the sample mold for preliminary drying, then place the sample mold into a hot press, perform hot pressing operation at a certain hot pressing temperature and hot pressing pressure, and demold and remove after cooling to room temperature to obtain the prepared PEO-based solid electrolyte.

3. A method for preparing a PEO-based solid electrolyte according to claim 2, characterized in that: In step S1, the reaction aids include a reaction solvent, an initiator and a molecular weight regulator. The reaction solvent is selected from one of toluene, n-hexane or dichloromethane to dissolve the silane monomer and the PEO polymer. The initiator is selected from one of benzoyl peroxide and dicumyl peroxide. The amount of the initiator is set in the range of 0.5%-0.8% of the mass of the PEO polymer and the silane. The molecular weight regulator is selected from one of propane, propylene or propionaldehyde.

4. A method for preparing a PEO-based solid electrolyte according to claim 3, characterized in that: In step S1, the PEO polymer, silane and reaction solvent are added to an ultrasonic stirrer, and ultrasonic stirring is performed for 10 minutes at 25° C. The ultrasonic frequency of the ultrasonic stirrer is 20KHz-60KHz, and the stirring speed is 250-1200rpm to obtain a mixture A. The obtained mixture A is added to a high-pressure reactor, and the reaction temperature is set to 80° C.-90° C. and the reaction pressure is set to 6-10MPa. The specific steps of the copolymerization reaction include: a. Add the mixture A in which the PEO polymer, silane and the reaction solvent are fully dissolved into a high-pressure reactor, and carry out a prepolymerization reaction at a reaction temperature of 80°C and a reaction pressure of 6.5MPa to generate a preliminary copolymer or active intermediate; b. Then, a continuous polymerization reaction was carried out at a reaction temperature of 85°C and a reaction pressure of 10 MPa, and various parameters such as temperature and pressure during the reaction were monitored in real time; c. After the reaction rate gradually decreases to a stable state, stop heating and slowly release the pressure, discharge the reaction product and successively filter, distill, wash and dry to obtain a silane-crosslinked modified PEO matrix.

5. The method for preparing a PEO-based solid electrolyte according to claim 2, characterized in that: The specific steps of preparing the [Li(CF3SO2)2N-10%LiPF6] dual lithium salt system conductive ion source in step S2 include: a. CF3SO2NH2 and a strong alkaline lithium salt LiOH are selected as reaction materials, added to a reactor for a preliminary reaction to generate an intermediate product CF3SO2NHLi, and then a quantitative amount of CF3SO2Cl is added for further reaction; b. Adding a quantitative lithium salt catalyst LiF at the same time, stirring at a temperature of -15 ℃ ~ 25 ℃, stirring at a speed of 200-500rpm to obtain a mixture B; c. Recrystallizing and drying the mixture B under reduced pressure to obtain Li(CF3SO2)2N crystals with high purity; d. Add a certain volume of HF solution to the reactor, select a certain amount of LiF and add the HF solution to continuously introduce PF5 gas at a low temperature of -30°C to -20°C and normal pressure to react to generate LiPF6 solution, and then perform recrystallization and vacuum drying to obtain LiPF6 crystals with high purity; e. Select appropriate amounts of Li(CF3SO2)2N crystals and LiPF6 crystals and fully dissolve them in a solvent to obtain a conductive ion source of the [Li(CF3SO2)2N-10%LiPF6] double lithium salt system.

6. A method for preparing a PEO-based solid electrolyte according to claim 2, characterized in that: In step S3, the amount of the acetone solvent is selected to be greater than the total amount of the modified PEO matrix, the lithium salt and the inorganic nanofiller, the modified PEO matrix and the [Li(CF3SO2)2N-10%LiPF6] lithium salt polymer are dissolved in the acetone solvent, and are fully dissolved in an ultrasonic agitator at a stirring temperature of 25°C to 30°C and a stirring speed of 200-1200rpm to obtain a mixture C.

7. The method for preparing a PEO-based solid electrolyte according to claim 6, characterized in that: In step S4, the inorganic nanofiller is selected from one or two of TiO2, Al2O3, BaTiO3 and ZnAl2O4, and a certain amount of inorganic nanofiller is added to the mixture C. It is fully stirred and dissolved in an ultrasonic stirrer at a stirring temperature of 25°C to 35°C and a stirring speed of 500-1500rpm to obtain an electrolyte solution.

8. The method for preparing a PEO-based solid electrolyte according to claim 2, characterized in that: The specific steps of obtaining the PEO-based solid electrolyte according to the electrolyte dissolution in step S5 include: a. Pour the electrolyte solution into the sample mold and perform preliminary drying at a temperature of 50°C-60°C to form a solid-slurry preliminary molding state; b. Place the sample mold into a hot press and perform hot pressing at a pressure of 10-15 MPa at 70°C-85°C; c. After the hot pressing is completed, the mixture is cooled to room temperature and the pressure is slowly released. The solid structure is demolded and taken out to obtain a PEO-based solid electrolyte. The hot-pressed PEO-based solid electrolyte is annealed to improve the ionic conductivity of the electrolyte.

9. Use of a PEO-based solid electrolyte obtained by the preparation method according to any one of claims 2 to 8 in a solid-state lithium-sulfur battery.

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