Solid-state electrolyte, method for preparing the same, battery, and power utilization device

Abstract

A preparation method of a solid-state electrolyte, comprising: preparing a filler: adding reactants 2,5-dihydroxyterephthaldehyde and triaminoguanidine hydrochloride into a solvent to mix, stirring the obtained reaction product to obtain a reaction product; adding the reaction product into a saturated sodium fluoride aqueous solution to stir to obtain a product; washing and drying the product to obtain the filler; mixing lithium bistrifluoromethylsulfonimide, vinylene carbonate, polyvinylidene fluoride-hexafluoropropylene copolymer, the filler, and an organic solvent, and then adding an initiator azobisisobutyronitrile to obtain a mixed slurry; drying the mixed slurry to obtain the solid-state electrolyte. The application also provides a composite solid-state electrolyte, a battery and an electric device. The solid-state electrolyte of the application combines the characteristics of the polymer electrolyte and the filler, improves the ion conductivity, and has better mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a solid-state electrolyte and a preparation method thereof, a battery containing the solid-state electrolyte and an electric device containing the battery. BACKGROUND

[0002] The energy density of existing lithium ion batteries will reach a bottleneck, which cannot well meet the demand of electric vehicles and grid energy storage industry for the energy density of rechargeable batteries. Although the use of lithium negative electrode with low redox potential but high activity can improve the energy density, the formation of inhomogeneous solid electrolyte interphase (SEI) when lithium metal contacts with electrolyte causes the loss of active lithium and is not conducive to the uniform deposition of lithium ions, which is easy to form lithium dendrites to trigger short circuit. In addition, the safety hidden danger caused by the intrinsic defects of organic electrolyte such as electrolyte leakage, high-pressure decomposition gas and high-temperature spontaneous combustion is high, and thermal runaway is easy to occur at high temperature. Using solid-state electrolyte to replace the electrolyte and separator in lithium metal battery is one of the solutions to inhibit dendrite growth and improve battery stability.

[0003] According to the different material composition and ion transport mechanism, the solid-state electrolyte is divided into inorganic solid-state electrolyte and polymer solid-state electrolyte. Compared with the polymer solid-state electrolyte, the inorganic solid-state electrolyte contacts with the positive and negative electrodes in a “point-point” manner, which increases the interface impedance, and its brittleness is difficult to prepare in a large area, which seriously limits the practicability. However, the existing polymer solid-state electrolyte has low ionic conductivity, which still cannot meet the practical demand. SUMMARY

[0004] In view of this, the first aspect of the present application provides a preparation method of a solid-state electrolyte, comprising:

[0005] Preparation of the filler, comprising:

[0006] adding the reactants 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride into the solvent to mix, stirring to obtain a reaction product;

[0007] adding the reaction product into the saturated sodium fluoride aqueous solution to stir, to obtain a product; and

[0008] washing and drying the product to obtain the filler;

[0009] Preparation of the mixed slurry, comprising: mixing lithium bistrifluoromethylsulfonylimide, vinylene carbonate, polyvinylidene fluoride-hexafluoropropylene copolymer, the filler and an organic solvent, and then adding an initiator azobisisobutyronitrile to obtain a mixed slurry; and

[0010] drying the mixed slurry to obtain the solid-state electrolyte.

[0011] The solid electrolyte preparation method of this application embodiment includes a filler material, which is a fluorinated covalent organic framework (F-COF) material. It also includes polyvinyl carbonate (PVC) as the polymer ion-conducting host and polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) as the mechanical support framework. The PVC in the solid electrolyte of this application embodiment has abundant -C=O groups, which can dissolve a large amount of LiTFSI, thus improving the ionic conductivity of the electrolyte. The -C=N and -NH groups in the F-COF filler material both promote Li+ dissociation and anchor TFSI. – This is beneficial for increasing the lithium-ion transference number, further enhancing the lithium-ion transport capability of the polymer solid electrolyte. The F- in the filler helps to construct a stable solid electrolyte interphase (SEI), ensuring uniform and dense lithium-ion deposition on the negative electrode surface. Furthermore, the excellent mechanical properties of PVDF-HFP maintain the stable morphology of the electrolyte, thereby suppressing dendrite formation and improving the cycle stability of the battery. The solid electrolyte of this application combines the characteristics of polymer electrolytes and fillers, improving the ionic conductivity of the polymer solid electrolyte while also giving it better mechanical properties, thus advancing the application development of polymer solid electrolytes.

[0012] In some embodiments, in the step of "adding reactants 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride to a solvent and mixing and stirring to react", the molar ratio of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride is (1~1.5):1.

[0013] In some embodiments, in the step of “adding reactants 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride to a solvent and mixing and stirring to react”, the solvent includes 1,4-dioxane and deionized water, wherein the volume ratio of 1,4-dioxane to deionized water is (3~5):(1~2).

[0014] In some embodiments, in the step of "washing and drying the product", the drying is vacuum drying, the drying temperature is 90℃~120℃, and the drying time is 12h~24h.

[0015] In some embodiments, in the step of "preparing the mixed slurry", the molar concentration of lithium bis(trifluoromethanesulfonyl)imide in the vinylene carbonate is 0.5~2.0 mol / L.

[0016] The mass of the polyvinylidene fluoride-hexafluoropropylene copolymer accounts for 15% to 17% of the total mass of the lithium bis(trifluoromethanesulfonyl)imide, the vinylene carbonate, the polyvinylidene fluoride-hexafluoropropylene copolymer, and the filler.

[0017] The mass of the filler accounts for 0 to 4% of the total mass of the lithium bis(trifluoromethanesulfonyl)imide, the vinylene carbonate, the polyvinylidene fluoride-hexafluoropropylene copolymer, and the filler, and the mass percentage of the filler does not include 0%.

[0018] In some embodiments, in the step of “preparing the mixed slurry”, the ratio of the initiator to the vinylene carbonate is (0.6~1.2) mg: 1 mL.

[0019] In some embodiments, in the step of "preparing the mixed slurry", the organic solvent is at least one selected from acetone, tetrahydrofuran, dimethyl sulfoxide, sulfolane, and N-methylpyrrolidone.

[0020] The step of "drying the mixed slurry" includes: applying the mixed slurry onto a rigid plate and allowing it to stand and be kept warm to obtain the solid electrolyte.

[0021] The second aspect of this application provides a composite solid electrolyte prepared by the method described in the first aspect. The composite solid electrolyte includes a filler, polyvinyl carbonate, and polyvinylidene fluoride-hexafluoropropylene copolymer. The filler is a fluoride of the reaction product of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride.

[0022] A third aspect of this application provides a battery including a negative electrode, a positive electrode, and a composite solid electrolyte as described in the second aspect disposed between the positive electrode and the negative electrode.

[0023] The fourth aspect of this application provides an electrical device that uses the battery described in the third aspect as a power source.

[0024] Using the aforementioned battery as a power source for electronic devices provides stable performance and ensures a consistent power supply. Attached Figure Description

[0025] Figure 1 The conductivity of solid electrolyte membranes with different lithium salt concentrations in Comparative Examples 1 to 8 is given.

[0026] Figure 2 The conductivity of solid electrolyte membranes with different PVDF-HFP addition amounts in Comparative Examples 9 to 11 is shown.

[0027] Figure 3 These are the conductivity of solid electrolyte membranes with different COF addition amounts.

[0028] Figure 4 This is a comparison graph of the cycle performance of lithium symmetric batteries using solid electrolyte membranes from Comparative Example 6 and Example 3.

[0029] Figure 5 This is a comparison graph of the cycle performance of lithium metal batteries using solid electrolyte membranes from Comparative Example 6 and Example 3. Detailed Implementation

[0030] To better understand the purpose, features, and advantages of this application, a detailed description of the application is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. Numerous specific details are set forth in the following description to provide a thorough understanding of this application; the described embodiments are only a part of the embodiments of this application, and not all of them.

[0031] The following will describe some embodiments of this application in detail with reference to the accompanying drawings. Unless otherwise specified, the data range values ​​described in this application should include the end values.

[0032] This application provides a solid electrolyte and its preparation method. The solid electrolyte comprises multiple components and can be referred to as a composite solid electrolyte. It uses a fluorinated covalent organic framework (F-COF) material as a filler, polyvinyl carbonate (PVC) as the polymer ion conduction host, and polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) as a mechanical support framework. This effectively increases the solubility of lithium salt in the composite solid electrolyte, thereby increasing its ionic conductivity and improving lithium ion migration ability.

[0033] The preparation method of this composite solid electrolyte includes the following steps S1 to S3.

[0034] S1: Preparation of packing material. S1 further includes S11 to S13.

[0035] S11: Add the reactants 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride to the solvent, mix, and stir to obtain the reaction product;

[0036] S12: After the reaction is complete, the reaction product is added to a saturated sodium fluoride aqueous solution and stirred to obtain the product;

[0037] S13: The product is washed and dried to obtain the filler.

[0038] In step S11, in some embodiments, the molar ratio of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride is (1~1.5):1. In some embodiments, the solvent includes 1,4-dioxane and deionized water, wherein the volume ratio of 1,4-dioxane to deionized water is (3~5):(1~2). In step S11, during stirring, argon gas may also be introduced to remove dissolved oxygen from the solution.

[0039] Step S12 involves ion-displacing the reaction product of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride obtained in step S11, thereby fluorinating it. In some embodiments, the mass ratio of saturated sodium fluoride solution to the powdered reaction product obtained in step S11 is approximately 4.2%.

[0040] Anhydrous ethanol can be used for washing in step S13.

[0041] In step S13, the drying is vacuum drying, with a drying temperature of 90℃~120℃ and a drying time of 12h~24h.

[0042] The filler is a fluorinated covalent organic framework (F-COF) material, which is a fluoride of the reaction product of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride.

[0043] S2: Preparation of mixed slurry, including: mixing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), vinylene carbonate (VC), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), filler and organic solvent, stirring to make the components uniformly mixed, and then adding initiator azobisisobutyronitrile (AIBN) to react and obtain mixed slurry.

[0044] In some embodiments, the molar concentration of LiTFSI dissolved in VC is 0.5~2.0 mol / L. The mass of PVDF-HFP accounts for 15%~17% of the total mass of LiTFSI, vinylene carbonate (VC), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and filler, and the mass of filler accounts for 0~4 wt% of the total mass of LiTFSI, vinylene carbonate (VC), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and filler.

[0045] In step S2, the ratio of initiator AIBN to VC is 0.6~1.2 mg:1 mL. AIBN is a commonly used azo initiator that decomposes uniformly at 45-65℃, producing only one type of free radical. The purpose of adding the initiator is to initiate the polymerization of vinylene carbonate (VC) to form polyvinyl carbonate (PVC).

[0046] The organic solvent in step S2 may be at least one of acetone, tetrahydrofuran, dimethyl sulfoxide, sulfolane, and N-methylpyrrolidone.

[0047] After adding the initiator AIBN in step S2, the entire solution system can be appropriately heated to a temperature of 45℃~60℃, so that the initiator can generate free radicals through thermal decomposition, thereby initiating the polymerization reaction of vinylene carbonate monomer molecules.

[0048] S3: Dry the mixed slurry to remove the organic solvent and obtain a solid electrolyte.

[0049] In some embodiments, step S3 includes applying the mixed slurry onto a smooth, rigid plate, allowing it to stand, maintaining a certain temperature, and then drying it to obtain a composite solid electrolyte. The temperature maintained is 50–70°C, and the time is 8–16 hours. This step S3 can be achieved by controlling the amount of mixed slurry applied to the rigid plate to obtain a film-like solid electrolyte of a certain thickness.

[0050] In some embodiments, the thickness of the solid electrolyte is 5–100 μm. The thickness of the solid electrolyte can be in the following ranges: 5–20 μm, 20–40 μm, 40–60 μm, 60–80 μm, or 80–100 μm.

[0051] This application also provides a composite solid electrolyte obtained by the above preparation method. The composite solid electrolyte comprises: a fluorinated covalent organic framework (a fluoride of the reaction product of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride) as a filler, polyvinyl carbonate (PVC) as a polymer ion-conducting host, and polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) as a mechanical support skeleton.

[0052] The PVC in the polymer solid electrolyte of this application has abundant -C=O groups, which can dissolve a large amount of LiTFSI, thus improving the ionic conductivity of the electrolyte. The -C=N and -NH groups in the filler can both promote Li+ dissociation and anchor TFSI. – This is beneficial for increasing the lithium-ion transference number and further enhancing the lithium-ion transport capability of polymer solid electrolytes.

[0053] The F- in the filler is beneficial for constructing a stable solid electrolyte interphase (SEI), ensuring uniform and dense lithium ion deposition on the negative electrode surface, and utilizing the good mechanical properties of PVDF-HFP to maintain the stable morphology of the electrolyte, thereby suppressing dendrite formation and improving the cycle stability of the battery.

[0054] The composite solid electrolyte of this application combines the characteristics of polymer electrolytes and fillers, improving the ionic conductivity of polymer solid electrolytes while giving them better mechanical properties, thus promoting the application development of polymer solid electrolytes.

[0055] This application also provides a battery, including a negative electrode, a positive electrode, and the aforementioned composite solid electrolyte disposed between the positive and negative electrode. This battery may be, for example, a stainless steel symmetrical battery, a lithium metal battery, or a lithium symmetrical battery, but is not limited thereto.

[0056] This application provides an electrical device that uses the aforementioned battery as a power source.

[0057] The application of the battery in this application is not particularly limited, and it can be used in any electrical device known in the prior art. For example, such electrical devices include, but are not limited to, laptops, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.

[0058] The technical solutions of the embodiments of this application will be further described below through specific examples.

[0059] Comparative Example 1

[0060] 71.77 mg LiTFSI was added to 0.5 mL VC, and together with 206.6 mg PVDF-HFP, it was added to 6 mL acetone and heated and stirred to ensure uniform mixing of all components. Subsequently, an initiator was added at a ratio of AIBN:VC = 1 mg / mL. The mixture was then cast onto a PP plate and allowed to stand at room temperature for 15 min to allow the acetone to evaporate completely. The PP plate was then transferred to a vacuum drying oven and kept at 60°C for 12 h. Finally, the obtained polymer electrolyte membrane was cut into 18 mm diameter discs for battery assembly.

[0061] Comparative Example 2

[0062] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 143.54 mg.

[0063] Comparative Example 3

[0064] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 251.31 mg.

[0065] Comparative Example 4

[0066] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 229.66 mg.

[0067] Comparative Example 5

[0068] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 224.02 mg.

[0069] Comparative Example 6

[0070] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 258.37 mg.

[0071] Comparative Example 7

[0072] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 272.72 mg.

[0073] Comparative Example 8

[0074] It is basically the same as Comparative Example 1, except that the amount of LiTFSI added in Comparative Example 1 is changed to 287.08 mg.

[0075] Comparative Example 9

[0076] It is basically the same as Comparative Example 6, except that the amount of PVDF-HFP added in Comparative Example 6 is changed to 171.85 mg.

[0077] Comparative Example 10

[0078] It is basically the same as Comparative Example 6, except that the amount of PVDF-HFP added in Comparative Example 6 is changed to 206.6 mg.

[0079] Comparative Example 11

[0080] It is basically the same as Comparative Example 6, except that the amount of PVDF-HFP added in Comparative Example 6 is changed to 243.45 mg.

[0081] Example 1

[0082] Preparation of COF material filler: 0.45 mmol of 2,5-dihydroxyterephthalaldehyde and 0.3 mmol of triaminoguanidine hydrochloride were mixed and added to a slurry of 5 mL of 1,4-dioxane and 1.5 mL of deionized water. Argon gas was introduced while stirring to remove dissolved oxygen from the solution. After the reaction, the product was added to a saturated sodium fluoride aqueous solution and stirred. Finally, the product was washed with anhydrous ethanol and dried at 90 °C for 12 h to obtain the filler. Preparation of composite solid electrolyte membrane: 258.37 mg of LiTFSI was added to 0.5 mL of VC, and together with 206.6 mg of PVDF-HFP and 11.56 mg of filler, it was added to 6 mL of acetone and heated and stirred to mix the components uniformly. Then, an initiator was added at a ratio of AIBN:VC = 1 mg / mL. The mixed slurry was cast onto a PP plate and allowed to stand at room temperature for 15 min to allow the acetone to evaporate completely. The PP plate was then transferred to a vacuum drying oven and kept at 60 °C for 12 h.

[0083] Example 2

[0084] It is basically the same as Example 1, except that the amount of filler added in Example 1 is changed to 23.37 mg.

[0085] Example 3

[0086] It is basically the same as Example 1, except that the amount of filler added in Example 1 is changed to 35.4 mg.

[0087] Example 4

[0088] It is basically the same as Example 1, except that the amount of filler added in Example 1 is changed to 47.71 mg.

[0089] Application examples

[0090] The polymer electrolyte membranes obtained in Examples 1 to 4 and Comparative Examples 1 to 11 were cut into discs with a diameter of 18 mm for later use.

[0091] Assembly method of stainless steel symmetrical battery:

[0092] The battery is assembled using a φ15.8 mm stainless steel gasket and a composite solid electrolyte membrane in a stacking manner of negative electrode shell-spring sheet-gasket-solid electrolyte membrane-gasket-positive electrode shell.

[0093] Methods for preparing the positive electrode:

[0094] LiFePO4 (LFP), conductive carbon, and polyvinylidene fluoride (PVDF) were mixed evenly in N-methylpyrrolidone (NMP) reagent at a mass ratio of 8:1:1. The resulting slurry was then coated onto aluminum foil, and after vacuum drying and cutting, a positive electrode sheet was obtained.

[0095] Assembly method of lithium metal battery:

[0096] The spring clip and gasket are placed sequentially on the negative electrode shell of the 2025 battery case. After placing the lithium sheet in the center of the gasket, the solid electrolyte membrane is placed. The positive electrode sheet prepared according to the above method is placed on the composite solid electrolyte membrane, the positive electrode shell is covered, and the battery is pressed with a button cell packaging machine.

[0097] Assembly method of lithium symmetric battery:

[0098] The clamping spring and the gasket are placed sequentially on the negative electrode shell of the 2025 battery case. After placing the lithium sheet in the center of the gasket, the solid electrolyte membrane is placed. Another lithium sheet is clamped and placed on the composite solid electrolyte membrane. The positive electrode shell is then covered and pressed using a button battery packaging machine.

[0099] Conductivity testing methods:

[0100] Electrochemical impedance spectroscopy (EIS) was performed on a stainless steel symmetrical cell using a Gamry electrochemical workstation. The ionic conductivity was calculated using the formula: σ = L / AR, where L is the thickness of the solid electrolyte, A is the area of ​​the stainless steel sheet, and R is the measured impedance.

[0101] Lithium-ion symmetric battery cycle testing method:

[0102] The lithium-ion symmetric battery was cycle-tested using the Blue Battery Testing System at 60°C at a rate of 0.1 mA / cm². 2 and 0.1 mAh / cm 2 A conditional loop.

[0103] Lithium metal battery cycle testing method:

[0104] The lithium metal battery was cycled using the Blue Battery Testing System at 60°C with a 1C current and a charging voltage of 2.5~4.2 V.

[0105] Application Example 1

[0106] The composite solid electrolyte membranes of Comparative Example 6 and Example 3 were assembled into lithium symmetric batteries in the manner described above and placed on an electrochemical platform for electrochemical performance testing.

[0107] Application Example 2

[0108] The composite solid electrolyte membranes of Comparative Example 6 and Example 3 were assembled into lithium metal batteries in the manner described above and placed on an electrochemical platform for electrochemical performance testing.

[0109] Results analysis:

[0110] The conductivity test results of the composite solid electrolyte membranes of Comparative Examples 1 to 11 and Examples 1 to 4 at different temperatures are shown in Table 1 below.

[0111] As shown in Table 1 and Figure 1 As shown, by comparing Comparative Examples 1 to 8, the composite solid electrolyte membrane prepared in Comparative Example 7 (i.e., when 272.72 mg of LiTFSI was added, i.e., the concentration of LiTFSI in VC was 1.9 mol / L) had higher conductivity.

[0112] In Comparative Examples 9 to 11, the concentration of LiTFSI in VC was 1.8 mol / L. Figure 2 As shown, by comparing Comparative Examples 9 to 11, when the concentration of LiTFSI in VC is fixed at 1.8 mol / L, the composite solid electrolyte membrane prepared in Comparative Example 9 (i.e., when the PVDF-HFP content is 15.5%wt%) has higher conductivity.

[0113] In Comparative Example 6 and Examples 1 to 4, 258.37 mg of LiTFSI was added to 0.5 mL of vitamin C, meaning the concentration of LiTFSI in vitamin C was the same. Figure 3 As shown, by comparing Comparative Example 6 with Examples 1 to 4, the conductivity of the composite solid electrolyte membrane was significantly improved after the addition of filler. With the increase of filler content, the ionic conductivity of the composite solid electrolyte showed a phenomenon of first increasing and then decreasing. The ionic conductivity was the highest when the filler content was 3.0 wt%.

[0114] Table 1

[0115]

[0116] Figure 4 For the lithium-symmetric battery assembled using the solid electrolytes of Comparative Example 6 and Example 3, the current density was 0.1 mA / cm² at 60°C. 2 The deposition capacity is 0.1 mAh / cm³. 2 The battery assembled using the electrolyte of Comparative Example 6 showed a significant increase in polarization voltage after 800 h of cycling, while the battery assembled using the electrolyte of Example 3 maintained a nearly constant polarization voltage (approximately 40 mV) for 1500 h of stable cycling. This clearly demonstrates that the addition of filler can improve the cycle stability of the battery.

[0117] Figure 5The cycling performance of lithium metal batteries assembled using the solid electrolytes of Comparative Example 6 and Example 3 was measured at 60°C and a current density of 1.0 C. The battery with the electrolyte of Comparative Example 6 quickly exhibited severe overcharging due to localized micro-short circuits caused by lithium dendrites at 1C rate cycling; in contrast, the battery with the electrolyte of Example 3 still maintained a discharge capacity of 113.2 mAh / g even after 550 cycles, demonstrating good electrochemical stability and dendrite suppression capability.

[0118] The improved lithium salt solubility in the composite solid electrolyte of this application enhances the ionic conductivity of the electrolyte, and the addition of COF filler comprehensively improves the ion transport capacity of the polymer solid electrolyte. Furthermore, the filler plays a positive role in the formation of the solid electrolyte interphase (SEI) at the negative electrode. The polymer solid electrolyte of this application uses PVDF-HFP as a mechanical support framework, enabling it to possess excellent ionic conductivity while ensuring good mechanical properties, thereby improving the interfacial stability and electrochemical performance of the battery.

[0119] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A method for preparing a solid electrolyte, characterized in that, include: Preparation of fillers, including: The reactants 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride were added to a solvent and mixed. The solvent included 1,4-dioxane and deionized water. The reaction was stirred to obtain the reaction product. The reaction product was added to a saturated sodium fluoride aqueous solution and stirred to obtain the product; and The product is washed and dried to obtain the filler. The preparation of a mixed slurry includes: mixing lithium bis(trifluoromethanesulfonyl)imide, vinylene carbonate, polyvinylidene fluoride-hexafluoropropylene copolymer, the filler, and an organic solvent, wherein the mass of the filler accounts for 0-4% of the total mass of the lithium bis(trifluoromethanesulfonyl)imide, vinylene carbonate, polyvinylidene fluoride-hexafluoropropylene copolymer, and the filler, and the mass percentage of the filler does not exceed 0%, followed by adding an initiator azobisisobutyronitrile to obtain the mixed slurry; and The mixed slurry was dried to obtain a solid electrolyte.

2. The method for preparing a solid electrolyte according to claim 1, characterized in that, The molar ratio of 2,5-dihydroxyterephthalaldehyde to triaminoguanidine hydrochloride is (1~1.5):

1.

3. The method for preparing a solid electrolyte according to claim 1, characterized in that, The volume ratio of the 1,4-dioxane to the deionized water is (3~5):(1~2).

4. The method for preparing a solid electrolyte according to claim 1, characterized in that, In the step of "washing and drying the product", the drying is vacuum drying, the drying temperature is 90℃~120℃, and the drying time is 12h~24h.

5. The method for preparing a solid electrolyte according to claim 1, characterized in that, In the step of "preparing the mixed slurry", the molar concentration of lithium bis(trifluoromethanesulfonyl)imide in the vinylene carbonate is 0.5~2.0 mol / L. The mass of the polyvinylidene fluoride-hexafluoropropylene copolymer accounts for 15% to 17% of the total mass of the lithium bis(trifluoromethanesulfonyl)imide, the vinylene carbonate, the polyvinylidene fluoride-hexafluoropropylene copolymer, and the filler.

6. The method for preparing a solid electrolyte according to claim 1, characterized in that, In the step of "preparing the mixed slurry", the ratio of the initiator to the vinylene carbonate is (0.6~1.2) mg: 1 mL.

7. The method for preparing a solid electrolyte according to claim 1, characterized in that, In the step of "preparing the mixed slurry", the organic solvent is at least one of acetone, tetrahydrofuran, dimethyl sulfoxide, sulfolane, and N-methylpyrrolidone. The step of "drying the mixed slurry" includes: applying the mixed slurry onto a rigid plate and allowing it to stand and be kept warm to obtain the solid electrolyte.

8. A solid electrolyte, characterized in that, The solid electrolyte is prepared by the preparation method according to any one of claims 1 to 7, and the solid electrolyte includes a filler, polyvinyl carbonate and polyvinylidene fluoride-hexafluoropropylene copolymer, wherein the filler is a fluoride of the reaction product of 2,5-dihydroxyterephthalaldehyde and triaminoguanidine hydrochloride.

9. A battery, comprising a negative electrode and a positive electrode, characterized in that, It also includes the solid electrolyte as described in claim 8, disposed between the positive electrode and the negative electrode.

10. An electrical device, characterized in that, The battery as described in claim 9 is used as the power source.

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