Solid-state electrolyte, battery and preparation method thereof

Abstract

The application relates to the technical field of lithium batteries, in particular to a solid electrolyte, a battery and a preparation method thereof. In the application, fluorine polymers (including a composite of multiple fluorine polymers) are used as a matrix, ion plastic crystals and lithium salts are introduced, the component structure is adjusted and controlled, and the proportion of each component is optimized, so that a fluorine polymer / plastic crystal solid electrolyte is prepared. In the application, the solid electrolyte prepared by the above method has high room temperature ionic conductivity, and can realize fast charging and long cycle of a lithium secondary battery.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a solid electrolyte, a battery, and a method for preparing the same. Background Technology

[0002] With the increasing energy density of lithium-ion batteries, the safety hazards of traditional organic liquid electrolytes, such as flammability, volatility, and leakage, are becoming increasingly prominent. Compared with liquid electrolytes, solid electrolytes offer high safety, a wide electrochemical window, a wide operating temperature range, and also possess a certain degree of flexibility and high mechanical strength. They can effectively suppress lithium dendrite penetration during battery cycling, making it possible to use metallic lithium, which has a high theoretical specific capacity (3860 mAh / g) and the lowest negative potential (-3.04 V compared to the standard hydrogen electrode), as the negative electrode. This has attracted great attention from both academia and industry.

[0003] Polymer electrolytes, mainly composed of a polymer matrix and lithium salts, have attracted widespread attention due to their lightweight, good mechanical flexibility, controllable dimensions, and excellent processing performance. Among them, polymer electrolytes using fluoropolymers as the matrix have been developed. However, how to provide a solid-state electrolyte with high room temperature ionic conductivity that enables fast charging and long cycling of lithium secondary batteries remains a continuous exploration for those skilled in the art. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a solid-state electrolyte, a battery, and a method for preparing the same. The present invention uses a fluoropolymer (including a composite of multiple fluoropolymers) as a matrix, introduces ion-plastic crystals and lithium salts, and prepares a fluoropolymer / plastic crystal solid-state electrolyte by controlling the component structure and optimizing the proportions of each component. This solid-state electrolyte exhibits high room-temperature ionic conductivity and, for the first time, achieves fast charging and long cycle life for lithium-ion secondary batteries.

[0005] In this invention, fluoropolymers mainly refer to polymers formed by replacing all or part of the hydrogen atoms in the main chain and side chains of organic polymers with carbon atoms through covalent bonds. They have excellent properties such as outstanding chemical resistance, climate stability, low surface energy, and low friction coefficient.

[0006] For polymer electrolytes, in order to simultaneously achieve mechanical properties and ion conductivity, those skilled in the art are dedicated to exploring solid-state materials with high ion conductivity. Plastic crystals belong to the category of solid-state crystal materials. Due to the translational or rotational motion of their molecules / ions, resulting in disordered orientation and lattice vacancies, they exhibit solid-solid phase transition behavior before melting. The crystals exhibit plastic characteristics between the solid-solid phase transition temperature and the melting point.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] The first objective of this invention is to provide a solid electrolyte, which is obtained by introducing ion-plastic crystals and lithium salts into a fluoropolymer matrix;

[0009] The mass ratio of fluoropolymer, ion-plastic crystal and lithium salt is 20:4 to 100:1 to 40.

[0010] In one embodiment of the present invention, the fluoropolymer is selected from one or more compounds shown in the following structural formulas;

[0011]

[0012] In formulas (1) to (6), the molecular weight of the polymer is 100,000 to 600,000; x, y, n and m in each structural formula are all independent positive integers.

[0013] In one embodiment of the present invention, the ionic plastic crystal is one or more of pyrrole-based ionic plastic crystals, piperidine-based ionic plastic crystals, or morpholine-based ionic plastic crystals.

[0014] In one embodiment of the present invention, the structural formula of the pyrrole-based ionic plastic crystal is shown in formula (7), the structural formula of the piperidine-based ionic plastic crystal is shown in formula (8), and the structural formula of the morpholine-based ionic plastic crystal is shown in formula (9).

[0015]

[0016] In Equations (7), (8) and (9), R1 is independently selected from -CH3 or -CH2CH3, and R2 is independently selected from -CH3, -CH2CH3 or -CH2CH2CH3.

[0017] In one embodiment of the present invention, the lithium salt is selected from one or more of lithium chloride, lithium sulfate, lithium carbonate, lithium acetate, lithium cobalt oxide, lithium nitrate or lithium phosphate.

[0018] A second objective of this invention is to provide a method for preparing a solid electrolyte, comprising the following steps:

[0019] Fluoropolymer, lithium salt and ion-plastic crystal are dissolved and mixed, then poured into a mold, and after solvent removal and drying, a solid electrolyte is obtained.

[0020] In one embodiment of the present invention, the temperature during the mixing process is 25–80°C;

[0021] The solvent removal process is carried out under an inert atmosphere at room temperature.

[0022] The drying process specifically includes vacuum drying and argon drying;

[0023] During the vacuum drying process, the temperature is 25–80℃ and the time is 8–48 hours;

[0024] During the argon drying process, the temperature is at room temperature and the time is 8 to 48 hours.

[0025] A third object of the present invention is to provide a battery containing the above-described solid electrolyte.

[0026] The fourth objective of this invention is to provide a method for preparing a battery, wherein a positive electrode sheet, an electrolyte membrane prepared from the above-mentioned solid electrolyte, and a negative electrode sheet are stacked in order from bottom to top to form a stack, and then the battery is obtained by stamping.

[0027] In one embodiment of the present invention, the positive electrode is a positive electrode using lithium iron phosphate / lithium cobalt oxide / lithium nickel cobalt manganese oxide as the positive electrode material;

[0028] The structural formula of lithium nickel cobalt manganese oxide is LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2 or LiNi 0.5 Co 0.3 Mn 0.2 One of the O2 types;

[0029] The negative electrode sheet is a negative electrode sheet using lithium as the negative electrode material.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] In this invention, the lattice of the ion-plastic crystal contains "vacancies" that move with the rotation of molecules or ions, giving the crystal high lithium-ion conductivity. Furthermore, the plastic crystal exhibits a molecularly ordered crystalline state at low temperatures and possesses one or more solid-solid phase transition temperatures before its melting point. Between these transition temperatures and the melting point, the crystal exhibits plastic characteristics, allowing for rapid ion transport within the plastic crystalline phase. Therefore, the most fundamental requirement for the plastic crystal is that it remains in the plastic crystalline phase within the battery's operating temperature range; that is, it must possess both a low solid-solid phase transition temperature and a high melting point. The solid electrolyte prepared using the aforementioned ion-plastic crystal has the advantage of high room-temperature ionic conductivity and enables fast charging and long cycle life of lithium-ion secondary batteries. Attached Figure Description

[0032] Figure 1 PP is an ion-plastic crystal 12 FSI's DSC curve;

[0033] Figure 2 The cycling performance of the Li / LiFePO4 battery containing a solid electrolyte prepared in Example 1 at 5C and 25°C was obtained.

[0034] Figure 3 The cycling performance of the Li / LiFePO4 battery containing a solid electrolyte prepared in Example 2 was obtained at 5C and 25°C.

[0035] Figure 4 This is a schematic diagram of the solid electrolyte membrane prepared in Example 3;

[0036] Figure 5 The temperature dependence of the ionic conductivity of the solid electrolyte prepared in Example 3;

[0037] Figure 6 The LSV curve of the solid electrolyte prepared in Example 3;

[0038] Figure 7 The cycling performance of the Li / LiFePO4 battery containing a solid electrolyte prepared in Example 3 at 5C and 25°C was obtained.

[0039] Figure 8 The cycling performance of the Li / LiFePO4 battery containing solid electrolyte prepared in Example 3 at 6C and 25°C is shown. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0041] Unless otherwise specified, all reagents used in the following embodiments are commercially available reagents, and all monitoring methods and techniques used are conventional detection methods and techniques in the field.

[0042] NMR characterization method for ion-plastic crystals: An AVANCE III HD 500 nuclear magnetic resonance spectrometer was used. Deuterated dimethyl sulfoxide (DMSO-d6) was used as the deuteration reagent. A small amount of the sample to be tested was fully dissolved in the deuteration reagent, then added dropwise to the analysis tube, sealed, and placed in the nuclear magnetic resonance spectrometer for measurement.

[0043] Ionic conductivity testing method: The resistance of the solid electrolyte membrane was obtained by using a CHI660E electrochemical workstation with an AC impedance test frequency range of 0.1Hz to 100KHz, a test AC amplitude of 5mV, and a test temperature of 30 to 70℃. The electrolyte conductivity was then calculated.

[0044] LSV testing method: The linear scanning voltammetry (LSV) method was applied to Li / SPE / SS batteries using a CHI660E electrochemical workstation. The test temperature was 25℃, the voltage measurement range was 2~6V, and the scan rate was 0.1mV / s to obtain the current-potential curve.

[0045] Battery charge and discharge test method: The capacity of the battery under different charge and discharge currents is tested using the Blue Electric test system under constant current conditions, and the specific capacity and cycle performance of the battery are determined.

[0046] In the following examples, N-methyl-N-ethylpiperidine difluorosulfonylimide (PP) 12 FSI is prepared by the following method:

[0047] (S1) Under Ar protection, 9.92 g (0.1 mol) of the first compound (purity: 98%) and 40 mL of ethyl acetate solvent (purity: AR) were stirred and mixed evenly in a flask to obtain the first mixture;

[0048] Then 21.8 g (0.2 mol) of bromoethane (purity: 99%) was added dropwise to the first mixture above, and the mixture was stirred at 50 °C for 24 hours to obtain the first solution. The solvent was removed by rotary evaporation of the first solution to obtain the crude product.

[0049] The crude product was then washed three times with anhydrous diethyl ether (purity: AR) and dried under vacuum at 70°C for 48 hours to obtain the second compound (PP). 12 Br);

[0050] (S2) Dissolve 16.11 g (0.0774 mol) of the second compound prepared in step (S1) in deionized water (25 mL), and then add dropwise a deionized solution of LiFSI (purity: battery grade) (wherein, the ratio of LiFSI to deionized water is 17.37 g (0.093 mol): 20 mL). When the mixture is almost unable to be stirred, add 100 mL of dichloromethane (purity: AR) and stir thoroughly for 8 h to obtain the second mixture.

[0051] Extract the second mixture in a separatory funnel, collect the lower dichloromethane phase, and wash three times with deionized water (25 mL each time), stirring for 15 min each time, until no Br is detected by AgNO3 in the aqueous layer. - The lower layer was collected, and dichloromethane was removed by rotary evaporation. The product was then vacuum dried at 80°C for 48 hours to obtain N-methyl-N-ethylpiperidine difluorosulfonylimide (PP). 12 FSI) Its DSC curve is as follows Figure 1 (As shown).

[0052] pass Figure 1It can be observed that the synthesized ionic plastic crystal PP 12 FSI exhibits two solid-solid phase transitions at -40℃ and -20℃, and a melting peak at 165℃, indicating that it can maintain a plastic crystalline phase over a wide temperature range close to room temperature. Therefore, further compositing it with lithium salts and polymers allows for rapid ion transfer within the plastic crystalline phase, potentially leading to the development of new fast-charging technologies for high-safety lithium batteries.

[0053] The chemical structural formula of the first compound is shown below:

[0054] Wherein, R1 is -CH3;

[0055] The chemical structural formula of the second compound is shown below:

[0056] Where R1 is -CH3, R2 is -CH2CH3, and X is Br.

[0057] In the following examples, N-methyl-N-ethylmorpholine difluorosulfonylimide (PPO) 12 FSI is prepared by the following method:

[0058] (S1) Under Ar protection, 10.1 g (0.1 mol) of the third compound (purity: 98%) and 40 mL of ethyl acetate solvent (purity: AR) were stirred and mixed evenly in a flask to obtain the third mixture;

[0059] Then, 21.8 g (0.2 mol) of bromoethane (purity: 99%) was added dropwise to the third mixture above, and the mixture was stirred at 50 °C for 24 hours. The solvent was removed by rotary evaporation to obtain the crude product; the crude product was then washed three times with anhydrous diethyl ether (purity: AR) and dried under vacuum at 70 °C for 48 hours to obtain the fourth compound (PPO). 12 Br);

[0060] (S2) Dissolve 15.3 g (0.0728 mol) of the fourth compound obtained in step (S1) in 25 mL of deionized water, and add dropwise a deionized solution of LiFSI (purity: battery grade) (wherein the ratio of LiFSI to deionized water is 17.37 g (0.093 mol): 20 mL). When the mixture is almost unable to be stirred, add 100 mL of dichloromethane (purity: AR) and stir thoroughly for 8 h to obtain the fourth mixture. Extract the fourth mixture in a separatory funnel, collect the lower dichloromethane phase, and add deionized water to wash three times (25 mL each time), stirring and washing for 15 min each time, until no Br is detected by AgNO3 in the aqueous layer. -The lower layer was collected, and dichloromethane was removed by rotary evaporation. The product was then dried under vacuum at 80°C for 48 hours to obtain N-methyl-N-ethylmorpholine difluorosulfonylimide (PPO). 12 FSI).

[0061] The chemical structural formula of the third compound is shown below:

[0062] Wherein, R1 is -CH3;

[0063] The chemical structural formula of the fourth compound is shown below:

[0064] Where R1 is -CH3, R2 is -CH2CH3, and X is Br.

[0065] Example 1

[0066] This embodiment prepares vinylidene fluoride-hexafluoropropylene (P(VDF-HFP))—N-methyl-N-ethylpiperidinebisfluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0067] P(VDF-HFP), PP 12 FSI and LiFSI were mixed at a mass ratio of 20:55:25 and stirred at 50°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water, resulting in a solid electrolyte membrane.

[0068] Its ionic conductivity at 25℃ is 8.5 × 10⁻⁶. -4 The Li / LiFePO4 battery exhibits an initial discharge specific capacity of 147.0 mAh / g at 0.2C and 25°C at 25°C after 800 cycles. The discharge specific capacity at 5C and 25°C is 127.3 mAh / g, with a capacity retention rate exceeding 99%. Figure 2 ).

[0069] Example 2

[0070] This embodiment prepares vinylidene fluoride-trifluoroethylene (P(VDF-TRFE))—N-methyl-N-ethylpiperidine difluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0071] P(VDF-TRFE), PP 12FSI and LiFSI were mixed at a mass ratio of 20:55:25 and stirred at 50°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water, resulting in a solid electrolyte membrane.

[0072] Its ionic conductivity at 25℃ is 8.7 × 10⁻⁶. -4 The Li / LiFePO4 battery exhibits an initial discharge specific capacity of 153.7 mAh / g at 0.2C and 25°C at 25°C after 1000 cycles. The discharge specific capacity at 5C and 25°C is 126 mAh / g, with a capacity retention rate exceeding 99%. Figure 3 ).

[0073] Example 3

[0074] This embodiment prepares vinylidene fluoride-trifluoroethylene-trifluorochloroethylene (P(VDF-TRFE-CTFE))—vinylidene fluoride-trifluoroethylene (P(VDF-TRFE))—N-methyl-N-ethylpiperidine difluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0075] Combine P(VDF-TRFE-CTFE), P(VDF-TRFE), PP 12 FSI and LiFSI were mixed at a mass ratio of 10:10:55:25 and stirred at 45°C for 12 hours to form a homogeneous solution. The solution was then cast onto a polytetrafluoroethylene template, and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum-dried at 60°C for 48 hours, followed by drying in an argon-filled glove box for 24 hours to remove residual solvent and water, yielding a solid electrolyte membrane. Figure 4 As shown, a uniform and transparent solid electrolyte membrane was obtained.

[0076] Its ionic conductivity at 25℃ is 9.15 × 10⁻⁶. -4 The Li / LiFePO4 battery exhibits an initial discharge specific capacity of 156.1 mAh / g at 25°C and 0.2C, with a first-cycle coulombic efficiency of 93.3%. After 2800 cycles, the discharge specific capacity at 5C and 25°C is 125 mAh / g, with a capacity retention of over 98%. After 1400 cycles, the discharge specific capacity at 6C and 25°C is 123 mAh / g, with a capacity retention of over 99%. Figures 5-8 ).

[0077] Example 4

[0078] This embodiment prepares vinylidene fluoride-trifluoroethylene (P(VDF-TRFE))-vinylidene fluoride-hexafluoropropylene (P(VDF-HFP))-N-methyl-N-ethylpiperidine difluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0079] P(VDF-TRFE), P(VDF-HFP), PP 12 FSI and LiFSI were mixed at a mass ratio of 10:10:55:25 and stirred at 45°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water, resulting in a solid electrolyte membrane.

[0080] Its ionic conductivity at 25℃ is 8.9 × 10⁻⁶. -4 The Li / LiFePO4 battery exhibits an initial discharge specific capacity of 156 mAh / g at 0.2C and 25°C at 25°C. After 800 cycles, the discharge specific capacity at 5C and 25°C is 125 mAh / g, with a capacity retention of approximately 99%.

[0081] Example 5

[0082] This embodiment prepares vinylidene fluoride-trifluoroethylene-trifluorochloroethylene (P(VDF-TRFE-CTFE))—vinylidene fluoride-trifluoroethylene (P(VDF-TRFE))—N-methyl-N-ethylmorpholine bis(fluorosulfonyl)imide (PPO) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0083] Combine P(VDF-TRFE-CTFE), P(VDF-TRFE), PPO 12 FSI and LiFSI were mixed at a mass ratio of 10:10:60:20 and stirred at 45°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water, resulting in a solid electrolyte membrane.

[0084] Its ionic conductivity at 25℃ is 9.07 × 10⁻⁶. -4 S / cm. Li / LiFePO4, the battery has an initial discharge specific capacity of 153mAh / g at 0.2C at 25℃, and a discharge specific capacity of 122mAh / g at 5C and 25℃ after 900 cycles, with a capacity retention of about 99%.

[0085] Comparative Example 1

[0086] This comparative example prepared vinylidene fluoride-hexafluoropropylene (P(VDF-HFP))—N-methyl-N-ethylpiperidinebisfluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0087] P(VDF-HFP), PP 12 FSI and LiFSI were mixed at a mass ratio of 20:20:25 and stirred at 50°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water, resulting in a solid electrolyte membrane.

[0088] Its ionic conductivity at 25℃ is 1×10 -4 The Li / LiFePO4 battery exhibits a first discharge specific capacity of 90.0 mAh / g at 25°C and 0.2C.

[0089] Comparative Example 2

[0090] This comparative example prepared vinylidene fluoride-hexafluoropropylene (P(VDF-HFP))—N-methyl-N-ethylpiperidinebisfluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0091] P(VDF-HFP), PP 12 FSI and LiFSI were mixed at a mass ratio of 20:40:25 and stirred at 50°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water, resulting in a solid electrolyte membrane.

[0092] Its ionic conductivity at 25℃ is 4×10⁻⁶. -4 The Li / LiFePO4 battery has a first discharge specific capacity of 110.0 mAh / g at 25°C and 0.2C.

[0093] Comparative Example 3

[0094] This comparative example prepared vinylidene fluoride-hexafluoropropylene (P(VDF-HFP))—N-methyl-N-ethylpiperidinebisfluorosulfonylimide (PP) by solution casting. 12FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0095] P(VDF-HFP), PP 12 FSI and LiFSI were mixed at a mass ratio of 20:80:25 and stirred at 50°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water. The resulting solid electrolyte membrane was very sticky and had poor mechanical properties.

[0096] Comparative Example 4

[0097] This comparative example prepared vinylidene fluoride (P(VDF))-N-methyl-N-ethylpiperidine difluorosulfonylimide (PP) by solution casting. 12 FSI—Lithium bis(fluorosulfonyl)imide (LiFSI) solid electrolyte.

[0098] P(VDF-HFP), PP 12 FSI and LiFSI were mixed at a mass ratio of 20:80:25 and stirred at 50°C for 12 hours to form a homogeneous solution. The solution was then poured onto a polytetrafluoroethylene template and most of the acetone was removed at room temperature under an Ar atmosphere. The electrolyte membrane was then vacuum dried at 60°C for 48 hours and then transferred to an argon-filled glove box for 24 hours to remove residual solvent and water. The resulting solid electrolyte membrane was very sticky and had poor mechanical properties.

[0099] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the interpretation of the present invention, without departing from the scope of the invention, should be within the protection scope of the present invention.

Claims

1. A solid electrolyte, characterized in that, It is obtained by introducing ion-plastic crystals and lithium salts into a fluoropolymer matrix; wherein the mass ratio of fluoropolymer, ion-plastic crystals and lithium salt is 20:4 to 100:1 to 40. The fluoropolymer is selected from one or more of the compounds shown in the following structural formulas; In formulas (2) to (6), the molecular weight of the polymer is 100,000 to 600,000; x, y, n and m in each structural formula are all independent positive integers. The lithium salt is selected from one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, or lithium difluorooxalateborate. The ion-plastic crystal is PPO. 12 FSI; The solid electrolyte has an ionic conductivity of 9.07 × 10⁻⁶ at 25 °C. -4 S / cm; Among them, PPO 12 FSI is prepared by the following method: (S1) The third compound was mixed with ethyl acetate solvent under Ar gas protection to obtain the third mixture; Add bromoethane dropwise to the third mixture above, stir, and then remove the solvent by rotary evaporation to obtain the crude product; The crude product was washed three times with anhydrous diethyl ether and dried under vacuum to obtain the fourth compound. (S2) After dissolving the fourth compound, add a deionized LiFSI solution dropwise until it is almost impossible to stir. Then add dichloromethane and stir thoroughly to obtain the fourth mixture. Extract the fourth mixture using a separatory funnel, collect the lower dichloromethane phase, and add deionized water to wash the mixture until no Br is detected in the aqueous layer using AgNO3. - The lower layer was collected, and dichloromethane was removed by rotary evaporation. The product was then dried under vacuum to obtain PPO. 12 FSI; The chemical structural formula of the third compound is shown below: Wherein, R1 is -CH3; The chemical structural formula of the fourth compound is shown below: Where R1 is -CH3, R2 is -CH2CH3, and X is Br.

2. The solid electrolyte according to claim 1, characterized in that, The fluoropolymer is selected from one of P(VDF-HFP), PVDF, P(VDF-CTFE), P(VDF-TrFE), P(VDF-TrFE-CTFE) or PTFE.

3. A method for preparing a solid electrolyte as described in any one of claims 1 to 2, characterized in that, Includes the following steps: Fluoropolymer, lithium salt and ion-plastic crystal are dissolved and mixed, then poured into a mold, and after solvent removal and drying, a solid electrolyte is obtained.

4. The method for preparing a solid electrolyte according to claim 3, characterized in that, During the mixing process, the temperature is 25–80℃; The solvent removal process is carried out under an inert atmosphere at room temperature. The drying process specifically includes vacuum drying and argon drying; During the vacuum drying process, the temperature is 25–80℃ and the time is 8–48 hours; During the argon drying process, the temperature is at room temperature and the time is 8 to 48 hours.

5. A battery, characterized in that, The battery contains the solid electrolyte as described in any one of claims 1 to 2.

6. A method for preparing a battery, characterized in that, The positive electrode, the electrolyte membrane prepared by the solid electrolyte according to any one of claims 1 to 2, and the negative electrode are stacked in order from bottom to top to form a stack, and then stamped to obtain a battery.

7. The method for preparing a battery according to claim 6, characterized in that, The positive electrode sheet is a positive electrode sheet using lithium iron phosphate / lithium cobalt oxide / lithium nickel cobalt manganese oxide as the positive electrode material; The structural formula of lithium nickel cobalt manganese oxide is LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2 or LiNi 0.5 Co 0.3 Mn 0.2 One of the O2 types; The negative electrode sheet is a negative electrode sheet using lithium as the negative electrode material.

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