A gel electrolyte, its preparation method and application

Abstract

This application belongs to the field of battery technology, specifically providing a gel electrolyte, its preparation method, and its application. The gel electrolyte includes an electrolyte and a polymer shown in structural formula (I). The beneficial effects of this application are: the gel electrolyte described in this application does not require curing during the preparation of semi-solid batteries and has high ionic conductivity and safety performance; because the gel electrolyte described in this application uses trifunctional triacrylate as a polymer monomer during the preparation process, and processes the trifunctional triacrylate into difunctional triacrylate, the hardness of the product is reduced, further improving the conductivity of the product; and then the difunctional triacrylate is reacted with polyethylene glycol diacrylate (PEGDA), which can reduce the crosslinking density of the product, improve ionic conductivity, and optimize the wetting performance of the electrolyte.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a gel electrolyte, its preparation method, and its application. Background Technology

[0002] With the rapid development of new energy vehicles, traditional power battery systems will struggle to meet the energy density demands of the next 10 years. Furthermore, while new energy vehicle sales are increasing year by year, so too are safety incidents, with battery spontaneous combustion accounting for 31% of all accidents. Spontaneous combustion occurs when a short circuit occurs inside or outside the lithium battery, causing it to release a large amount of heat in a short time, leading to a rapid temperature rise and thermal runaway. The flammable liquid electrolyte can then ignite at high temperatures, ultimately resulting in a battery fire or explosion.

[0003] Solid-state batteries replace flammable organic liquid electrolytes with non-flammable solid electrolytes, significantly improving the safety of battery systems. They also offer better compatibility with high-energy positive and negative electrodes, reduce system weight, and simultaneously increase energy density. Among various novel battery systems, solid-state batteries are the next-generation technology closest to industrialization, a consensus shared by industry and the scientific community. However, existing gel electrolytes require a certain temperature and time to solidify, a relatively long curing time that severely hinders their industrial production. Therefore, it is necessary to research and improve gel electrolytes. Summary of the Invention

[0004] This application provides a gel electrolyte, its preparation method, and its application, aiming to solve the problems of long curing time and low production efficiency of existing gel electrolytes.

[0005] A first aspect of this application provides a gel electrolyte comprising an electrolyte and a polymer of structural formula (I).

[0006]

[0007] Where 1≤x≤6, 5≤m≤500, and 1≤n≤5.

[0008] According to some embodiments of the gel electrolyte described in this application, the gel electrolyte further includes an initiator.

[0009] According to some embodiments of the gel electrolyte described in this application, the electrolyte includes a ternary electrolyte.

[0010] According to some embodiments of the gel electrolyte described in this application, the initiator includes one or both of benzoyl peroxide and dimethyl azobisisobutyrate.

[0011] According to some embodiments of the gel electrolyte described in this application, the mass ratio of the polymer to the electrolyte is (0.03-0.05):1.

[0012] According to some embodiments of the gel electrolyte described in this application, the mass ratio of the initiator to the electrolyte is (0.008-0.12):1.

[0013] The gel electrolyte described in this application has high ionic conductivity, excellent wetting effect, and does not require curing when preparing semi-solid batteries.

[0014] A second aspect of this application provides a method for preparing the gel electrolyte described in the first aspect of this application, comprising the following steps:

[0015] (1) Trifunctional triacrylate is treated to obtain difunctional triacrylate.

[0016] (2) The difunctional triacrylate, polyethylene glycol diacrylate and alkyl thiol are mixed and reacted to obtain the polymer shown in formula (I);

[0017] (3) Mix the polymer shown in formula (I) with the electrolyte to obtain the gel electrolyte.

[0018] The preparation method described in this application converts trifunctional triacrylate into difunctional triacrylate, which can reduce the hardness of the product and increase the ionic conductivity of the gel electrolyte. Further reaction with polyethylene glycol diacrylate can further improve the ionic conductivity and optimize the wettability of the electrolyte.

[0019] According to some embodiments of the gel electrolyte preparation method described in this application, the trifunctional triacrylate includes trimethylolpropane triacrylate.

[0020] According to some embodiments of the gel electrolyte preparation method described in this application, the step of treating the trifunctional triacrylate includes: mixing the trifunctional triacrylate and an alkyl thiol to carry out a first reaction to obtain a difunctional triacrylate.

[0021] According to some embodiments of the gel electrolyte preparation method described in this application, the alkyl thiol includes one or more of butanethiol, propanethiol, and ethanethiol.

[0022] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the trifunctional triacrylate to the alkyl thiol is 1:(0.1-2).

[0023] According to some embodiments of the gel electrolyte preparation method described in this application, the temperature of the first reaction is 15-35°C, and the time of the first reaction is 0.5-2h.

[0024] According to some embodiments of the gel electrolyte preparation method described in this application, the first reaction is carried out in a first solvent.

[0025] According to some embodiments of the gel electrolyte preparation method described in this application, the first solvent includes one or more of dioxapentane, dioxane, and tetrahydrofuran.

[0026] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the trifunctional triacrylate to the first solvent is 1:(3-10).

[0027] According to some embodiments of the gel electrolyte preparation method described in this application, the first reaction is carried out in the presence of a first catalyst.

[0028] According to some embodiments of the gel electrolyte preparation method described in this application, the first catalyst includes dimethylphenylphosphine.

[0029] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the trifunctional triacrylate to the first catalyst is 1:(0.005-0.05).

[0030] According to some embodiments of the gel electrolyte preparation method described in this application, the number average molecular weight of the polyethylene glycol diacrylate is 170-350.

[0031] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the difunctional triacrylate to the polyethylene glycol diacrylate is 1:(0.01-5).

[0032] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the difunctional triacrylate to the polyethylene glycol diacrylate is 1:(0.25-4).

[0033] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the difunctional triacrylate to the alkyl thiol is 1:(0.5-1.5).

[0034] According to some embodiments of the gel electrolyte preparation method described in this application, the temperature of the mixing reaction is 15-35°C, and the mixing reaction time is 0.5-4h.

[0035] According to some embodiments of the gel electrolyte preparation method described in this application, in step (2), the mixing reaction is carried out in a second solvent.

[0036] According to some embodiments of the gel electrolyte preparation method described in this application, the second solvent includes DMF and / or dimethylacetamide.

[0037] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the difunctional triacrylate to the second solvent is 1:(5-15).

[0038] According to some embodiments of the gel electrolyte preparation method described in this application, in step (2), the mixing reaction is carried out in the presence of a second catalyst.

[0039] According to some embodiments of the gel electrolyte preparation method described in this application, the second catalyst includes dimethylphenylphosphine.

[0040] According to some embodiments of the gel electrolyte preparation method described in this application, the molar ratio of the difunctional triacrylate to the second catalyst is 1:(0.005-0.05).

[0041] According to some embodiments of the gel electrolyte preparation method described in this application, the preparation of the gel electrolyte includes the following steps:

[0042] Monomer M1 trimethylolpropane triacrylate (TMPTA) and alkyl thiol are reacted to generate monomer M2 (BS-TMPTA), thereby converting trifunctional triacrylate into difunctional triacrylate. Monomer M2, alkyl thiol and polyethylene glycol diacrylate are reacted to generate a linear polymer. The linear polymer is added to a ternary electrolyte to prepare a gel electrolyte.

[0043] The specific reaction formula is shown below:

[0044]

[0045] Where 1≤x≤6, 5≤m≤500, and 1≤n≤5.

[0046] A third aspect of this application provides a semi-solid battery, comprising the gel electrolyte described in the first aspect of this application or the gel electrolyte obtained by the preparation method described in the second aspect of this application.

[0047] The semi-solid battery described in this application contains the gel electrolyte, which eliminates the need for curing, thus simplifying the preparation process of the semi-solid battery. Furthermore, if any ungelled monomers are present during the standing process, they can be further gelled during battery formation, improving the completeness of gel electrolyte curing and thereby enhancing the battery's electrical performance and safety. Attached Figure Description

[0048] Figure 1 This is a graph showing the capacity cycle retention of the semi-solid-state batteries prepared in Example 1 and Comparative Example 3 of this application. Detailed Implementation

[0049] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0050] The technical solution of this application will be described in detail below with reference to specific embodiments and accompanying drawings.

[0051] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0052] This application provides a gel electrolyte, comprising an electrolyte and a polymer of structural formula (I).

[0053]

[0054] Where 1≤x≤6, 5≤m≤500, and 1≤n≤5.

[0055] In some embodiments, the gel electrolyte further includes an initiator.

[0056] In some embodiments, the electrolyte comprises a ternary electrolyte.

[0057] In some embodiments, the initiator includes one or both of benzoyl peroxide and dimethyl azobisisobutyrate.

[0058] In some embodiments, the mass ratio of the polymer to the electrolyte is (0.03-0.05):1, for example, 0.03:1, 0.04:1, 0.05:1, etc.

[0059] In some embodiments, the mass ratio of the initiator to the electrolyte is (0.008-0.12):1, for example, 0.008:1, 0.01:1, 0.12:1, etc.

[0060] The gel electrolyte described in this application does not require curing during the preparation of semi-solid batteries and has high ionic conductivity.

[0061] This application also provides a method for preparing a gel electrolyte, comprising the following steps:

[0062] (1) Trifunctional triacrylate is treated to obtain difunctional triacrylate.

[0063] (2) The difunctional triacrylate, polyethylene glycol diacrylate and alkyl thiol are mixed and reacted to obtain the polymer shown in formula (I);

[0064] (3) The polymer shown in the linear formula (I) and the electrolyte are mixed to obtain the gel electrolyte.

[0065] Because trifunctional triacrylates have high reactivity, high crosslinking density, low volatility, low irritation, and good curing speed, they can be used as polymer monomers. Processing trifunctional triacrylates into difunctional triacrylates can reduce the hardness of the product and further improve the conductivity of the product. Then, reacting difunctional triacrylates with polyethylene glycol diacrylate (PEGDA) can reduce the crosslinking density of the product, improve the ionic conductivity, and optimize the wetting performance of the electrolyte.

[0066] In some embodiments, the step of treating the trifunctional triacrylate includes: mixing the trifunctional triacrylate and an alkyl thiol to carry out a first reaction to obtain a difunctional triacrylate. Converting the trifunctional triacrylate to a difunctional triacrylate can reduce the hardness of the product and increase the ionic conductivity of the gel electrolyte.

[0067] In some embodiments, the trifunctional triacrylate includes trimethylolpropane triacrylate.

[0068] In some embodiments, the alkyl thiol includes one or more of butanethiol, propanethiol, and ethanethiol.

[0069] In some embodiments, the molar ratio of the trifunctional triacrylate to the alkyl thiol is 1:(0.1-2), for example 1:0.1, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:2, etc.

[0070] In some embodiments, the temperature of the first reaction is 15-35°C, such as 15°C, 20°C, 25°C, 30°C, or 35°C, and the reaction time is 0.5-2 hours, such as 0.5 hours, 0.8 hours, 1.2 hours, 1.8 hours, or 2 hours.

[0071] In some embodiments, the first reaction is carried out in a first solvent.

[0072] In some embodiments, the first solvent includes one or more of dioxapentane, dioxane, and tetrahydrofuran.

[0073] In some embodiments, the molar ratio of the trifunctional triacrylate to the first solvent is 1:(3-10), for example, 1:3, 1:5, 1:8, 1:10, etc.

[0074] In some embodiments, the first reaction is carried out in the presence of a first catalyst.

[0075] In some embodiments, the first catalyst comprises dimethylphenylphosphine.

[0076] In some embodiments, the molar ratio of the trifunctional triacrylate to the first catalyst is 1:(0.005-0.05), for example 1:0.005, 1:0.008, 1:0.01, 1:0.02, 1:0.04, or 1:0.05.

[0077] In some embodiments, the number-average molecular weight of the polyethylene glycol diacrylate is 170-350.

[0078] In some embodiments, the molar ratio of the difunctional triacrylate to the polyethylene glycol diacrylate is 1:(0.01-5), for example, 1:0.01, 1:0.1, 1:1, 1:2, 1:3, 1:4, or 1:5. Choosing this molar ratio ensures that the prepared gel electrolyte has good ionic conductivity and good curing effect.

[0079] In some embodiments, the molar ratio of the difunctional triacrylate to the alkyl thiol is 1:(0.5-1.5), for example, 1:0.5, 1:0.8, 1:1.2, 1:1.5, etc.

[0080] In some embodiments, the mixing reaction temperature is 15-35℃, such as 15℃, 20℃, 25℃, 30℃, 35℃, etc., and the mixing reaction time is 0.5-4h, such as 0.5h, 0.8h, 1.2h, 1.5h, 2h, 3h, 3.5h, 4h, etc. If the mixing reaction temperature is too high, the reaction rate will accelerate, causing the reaction to occur before the mixture has had time to be evenly mixed. If the temperature is too low, the reaction time will be prolonged, which will affect the curing effect of the product.

[0081] In some embodiments, in step (2), the mixing reaction is carried out in a second solvent.

[0082] In some embodiments, the second solvent comprises DMF and / or dimethylacetamide.

[0083] In some embodiments, the molar ratio of the difunctional triacrylate to the second solvent is 1:(5-15), for example, 1:5, 1:8, 1:10, 1:12, 1:15, etc.

[0084] In some embodiments, in step (2), the mixing reaction is carried out in the presence of a second catalyst.

[0085] In some embodiments, the second catalyst comprises dimethylphenylphosphine.

[0086] In some embodiments, the molar ratio of the difunctional triacrylate to the second catalyst is 1:(0.005-0.05), for example 1:0.005, 1:0.008, 1:0.01, 1:0.02, 1:0.04, or 1:0.05.

[0087] In some embodiments, in step (3), the polymer shown in formula (I) and the electrolyte are reacted with an initiator to form a gel electrolyte.

[0088] This application also provides a semi-solid battery, including the gel electrolyte described in this application and the gel electrolyte obtained by the preparation method of this application.

[0089] The semi-solid battery in this embodiment contains the gel electrolyte, which eliminates the need for curing, simplifying the preparation process of the semi-solid battery. Furthermore, if any ungelled monomers are present during the standing process, they can be further gelled during battery formation, improving the completeness of gel electrolyte curing and thus enhancing the battery's electrical performance and safety.

[0090] Example 1

[0091] (I) Preparation of Gel Electrolytes

[0092] Monomers M1 trimethylolpropane triacrylate (1 mol) and butanethiol (1 mol) were dissolved in 576 g of tetrahydrofuran (THF) solvent, and the catalyst dimethylphenylphosphine (0.03 mol) was added. The mixture was stirred at 0 °C until homogeneous, and then reacted at room temperature for 1 h. The product was then separated and purified by column chromatography to obtain monomer M2.

[0093] Monomer M2 (0.5 mol), polyethylene glycol diacrylate (0.5 mol) with a number average molecular weight of 214, and butanethiol (1 mol) were dissolved in 730 g of dimethylacetamide (DMAc) solvent. Dimethylphenylphosphine (0.01 mol) was added, and the mixture was stirred at 0 °C until homogeneous. The mixture was then allowed to react at room temperature for 2 h to obtain a linear polymer.

[0094] The linear polymer was added to a ternary electrolyte at a mass of 4% of the electrolyte mass, and benzoyl peroxide initiator was added at a mass of 1% of the electrolyte mass. The mixture was then mixed to obtain a gel electrolyte.

[0095] Example 2

[0096] The only difference between Example 2 and Example 1 is that in the preparation of the gel electrolyte in Example 2, the amount of monomer M2 added is 0.2 mol, and the amount of polyethylene glycol diacrylate with a number average molecular weight of 214 added is 0.8 mol, that is, the molar ratio of monomer M2 to polyethylene glycol diacrylate is 1:4.

[0097] The specific steps are as follows:

[0098] Monomers M1 trimethylolpropane triacrylate (1 mol) and butanethiol (1 mol) were dissolved in 576 g of tetrahydrofuran (THF) solvent, and the catalyst dimethylphenylphosphine (0.03 mol) was added. The mixture was stirred at 0 °C until homogeneous, and then reacted at room temperature for 1 h. The product was then separated and purified by column chromatography to obtain monomer M2.

[0099] Monomer M2 (0.2 mol), polyethylene glycol diacrylate (0.8 mol), and butanethiol (1 mol) were dissolved in 730 g of dimethylacetamide (DMAc) solvent. Dimethylphenylphosphine (0.01 mol) was added, and the mixture was stirred at 0 °C until homogeneous. The mixture was then allowed to react at room temperature for 2 h to obtain a linear polymer.

[0100] The linear polymer was added to a ternary electrolyte at a mass of 4% of the electrolyte mass, and benzoyl peroxide initiator was added at a mass of 1% of the electrolyte mass. The mixture was then mixed to obtain a gel electrolyte.

[0101] Example 3

[0102] The only difference between Example 3 and Example 1 is that in the preparation of the gel electrolyte in Example 3, the amount of monomer M2 added is 0.8 mol, and the amount of polyethylene glycol diacrylate with a number average molecular weight of 214 added is 0.2 mol, that is, the molar ratio of monomer M2 to polyethylene glycol diacrylate is 1:0.25.

[0103] The specific steps are as follows:

[0104] Monomers M1 trimethylolpropane triacrylate (1 mol) and butanethiol (1 mol) were dissolved in 576 g of tetrahydrofuran (THF) solvent, and the catalyst dimethylphenylphosphine (0.03 mol) was added. The mixture was stirred at 0 °C until homogeneous, and then reacted at room temperature for 1 h. The product was then separated and purified by column chromatography to obtain monomer M2.

[0105] Monomer M2 (0.8 mol), polyethylene glycol diacrylate (0.2 mol), and butanethiol (1 mol) were dissolved in 730 g of dimethylacetamide (DMAc) solvent. Dimethylphenylphosphine (0.01 mol) was added, and the mixture was stirred at 0 °C until homogeneous. The mixture was then allowed to react at room temperature for 2 h to obtain a linear polymer.

[0106] The linear polymer was added to a ternary electrolyte at a mass of 4% of the electrolyte mass, and benzoyl peroxide initiator was added at a mass of 1% of the electrolyte mass. The mixture was then mixed to obtain a gel electrolyte.

[0107] Comparative Example 1

[0108] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not add polyethylene glycol diacrylate during the preparation process, while the rest of the operation is the same as that of Example 1.

[0109] The specific steps are as follows:

[0110] Monomers M1 trimethylolpropane triacrylate (1 mol) and butanethiol (1 mol) were dissolved in 576 g of tetrahydrofuran (THF) solvent, and the catalyst dimethylphenylphosphine (0.03 mol) was added. The mixture was stirred at 0 °C until homogeneous, and then reacted at room temperature for 1 h. The product was then separated and purified by column chromatography to obtain monomer M2.

[0111] Monomer M2 (0.5 mol) and butanethiol (1 mol) were dissolved in 730 g of dimethylacetamide (DMAc) solvent, and dimethylphenylphosphine (0.01 mol) was added. The mixture was stirred at 0 °C until homogeneous, and then reacted at room temperature for 2 h to obtain a linear polymer.

[0112] The linear polymer was added to a ternary electrolyte at a mass of 4% of the electrolyte mass, and benzoyl peroxide initiator was added at a mass of 1% of the electrolyte mass. The mixture was then mixed to obtain a gel electrolyte.

[0113] Comparative Example 2

[0114] The only difference between Comparative Example 2 and Example 1 is that no monomer M2 is added during the preparation process of Comparative Example 2.

[0115] The specific steps are as follows:

[0116] Polyethylene glycol diacrylate (0.5 mol) and butanethiol (1 mol) were dissolved in 730 g of dimethylacetamide (DMAc) solvent, and dimethylphenylphosphine (0.01 mol) was added. The mixture was stirred at 0 °C until homogeneous, and then reacted at room temperature for 2 h to obtain a linear polymer.

[0117] The linear polymer was added to a ternary electrolyte at a mass of 4% of the electrolyte mass, and benzoyl peroxide initiator was added at a mass of 1% of the electrolyte mass. The mixture was then mixed to obtain a gel electrolyte.

[0118] Comparative Example 3

[0119] A conventional ternary electrolyte was used as a comparative example 3.

[0120] Comparative Example 4

[0121] The only difference between Comparative Example 4 and Example 1 of this application is that a linear polymer is prepared by directly reacting a trifunctional triacrylate with polyethylene glycol diacrylate.

[0122] Monomer M1 (0.5 mol), polyethylene glycol diacrylate (0.5 mol), and butanethiol (1 mol) were dissolved in 730 g of dimethylacetamide (DMAc) solvent. Dimethylphenylphosphine (0.01 mol) was added, and the mixture was stirred at 0 °C until homogeneous. The mixture was then allowed to react at room temperature for 2 h to obtain a linear polymer.

[0123] The linear polymer was added to a ternary electrolyte at a mass of 4% of the electrolyte mass, and benzoyl peroxide initiator was added at a mass of 1% of the electrolyte mass. The mixture was then mixed to obtain a gel electrolyte.

[0124] (II) Preparation of Semi-Solid-State Batteries

[0125] S1. Preparation of the positive electrode sheet: Preparation of the positive electrode material layer: Weigh out 97.5% lithium nickel cobalt manganese oxide, 1.25% polyvinylidene fluoride binder, 0.75% conductive carbon black, and 0.5% single-walled carbon nanotubes by weight. First, add polyvinylidene fluoride to N-methylpyrrolidone solvent to prepare a slurry. Then, add conductive carbon black and single-walled carbon nanotubes to the above slurry and stir until uniform. Then, add lithium nickel cobalt manganese oxide to the above slurry and stir until uniform. Finally, coat the slurry onto the current collector and dry it to prepare the positive electrode sheet. After rolling and slitting, obtain small positive electrode sheets.

[0126] S2. Preparation of negative electrode sheet: Weigh out 85% graphite negative electrode material, 10% silicon suboxide negative electrode material, 2.25% negative electrode binder polyacrylic acid, 0.75% negative electrode conductive agent conductive carbon black, 0.5% negative electrode conductive agent conductive carbon black, and 1.5% styrene-butadiene rubber by weight. First, add polyacrylic acid to deionized water to prepare a glue solution. Then, add conductive carbon black, graphite, and silicon oxide to the above glue solution and stir until uniform. Then, add styrene-butadiene rubber. Finally, coat the slurry onto the current collector and dry it to prepare the negative electrode sheet. After rolling and slitting, obtain small negative electrode sheets.

[0127] S3. Cell preparation: The positive and negative electrode small pieces are vacuum baked at 85℃ for 24 hours, and then stacked to form a cell and encapsulated in an aluminum-plastic film.

[0128] S4. The gel electrolytes prepared in this embodiment and the comparative embodiment are injected into the baked cells respectively. After formation, aging and capacity testing, a semi-solid battery is obtained.

[0129] The performance of the gel electrolytes and semi-solid batteries prepared in Examples 1-3 and Comparative Examples 1-4 of this application was tested, and the test results are shown in Table 1.

[0130] The testing method is as follows:

[0131] The internal resistance of the capacitor is tested using a voltage resistance tester.

[0132] Cyclic performance: The cycling performance of charging to 4.2V at 0.5C constant current and constant voltage at 25℃, resting for 10min and then discharging to 2.75V at 1C constant current.

[0133] Needle penetration: The needle penetration test of this application was conducted in accordance with GB31485-2020 Safety Requirements and Test Methods for Power Batteries for Electric Vehicles. The higher the needle penetration pass rate, the better the safety of the battery.

[0134] Table 1

[0135]

[0136]

[0137] As can be seen from Table 1, the gel electrolyte obtained by the preparation method described in this application has high safety. The higher the needle penetration rate, the better the safety of the battery prepared by the gel electrolyte prepared in this application. Furthermore, the performance of the gel electrolyte can be further optimized by adjusting the amount of monomer M2 and polyethylene glycol diacrylate added.

[0138] The semi-solid-state batteries prepared in Examples 1 and 3 of this application exhibit the following capacity cycle retention rates at 25°C, 0.5C charging, and 1C discharging: Figure 1 As shown:

[0139] from Figure 1 As can be seen from this, the semi-solid battery prepared by the gel electrolyte prepared in Example 1 of this application has better room temperature cycle performance than the one prepared by the gel electrolyte described in Comparative Example 3. That is, the gel electrolyte obtained by the preparation method described in this application can improve the cycle performance of the battery.

[0140] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A gel electrolyte, characterized in that, Includes an electrolyte, an initiator, and a polymer of structural formula (I). Where 1≤x≤6, 5≤m≤500, and 1≤n≤5.

2. The gel electrolyte according to claim 1, characterized in that, The electrolyte includes a ternary electrolyte; And / or, the initiator includes one or both of benzoyl peroxide and dimethyl azobisisobutyrate; And / or, the mass ratio of the polymer to the electrolyte is (0.03-0.05):1; And / or, the mass ratio of the initiator to the electrolyte is (0.008-0.12):

1.

3. A method for preparing the gel electrolyte according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Trifunctional triacrylate is treated to obtain difunctional triacrylate. (2) The difunctional triacrylate, polyethylene glycol diacrylate and alkyl thiol are mixed and reacted to obtain the polymer shown in formula (I); (3) The polymer, electrolyte and initiator shown in formula (I) are mixed to obtain the gel electrolyte.

4. The method for preparing the gel electrolyte according to claim 3, characterized in that, The trifunctional triacrylates include trimethylolpropane triacrylate; And / or, the step of treating the trifunctional triacrylate includes: mixing the trifunctional triacrylate and an alkyl thiol to carry out a first reaction to obtain a difunctional triacrylate.

5. The method for preparing the gel electrolyte according to claim 4, characterized in that, The alkyl thiols include one or more of butanethiol, propanethiol, and ethanethiol.

6. The method for preparing the gel electrolyte according to claim 4, characterized in that, The molar ratio of the trifunctional triacrylate to the alkyl thiol is 1:(0.1-2).

7. The method for preparing the gel electrolyte according to claim 4, characterized in that, The temperature of the first reaction is 15-35℃; the reaction time is 0.5-2h.

8. The method for preparing the gel electrolyte according to claim 4, characterized in that, The first reaction is carried out in the first solvent; The first solvent includes one or more of dioxapentane, dioxane, and tetrahydrofuran.

9. The method for preparing the gel electrolyte according to claim 8, characterized in that, The molar ratio of the trifunctional triacrylate to the first solvent is 1:(3-10); And / or, the first reaction is carried out in the presence of a first catalyst; the first catalyst comprises dimethylphenylphosphine.

10. The method for preparing the gel electrolyte according to claim 9, characterized in that, The molar ratio of the trifunctional triacrylate to the first catalyst is 1:(0.005-0.05).

11. The method for preparing the gel electrolyte according to claim 4, characterized in that, In step (2), the number average molecular weight of the polyethylene glycol diacrylate is 170-350 g / mol; And / or, the molar ratio of the difunctional triacrylate to the polyethylene glycol diacrylate is 1:(0.01-5); And / or, the molar ratio of the difunctional triacrylate to the alkyl thiol is 1:(0.5-1.5); And / or, the temperature of the mixing reaction is 15-35°C, and the time of the mixing reaction is 0.5-4h.

12. The method for preparing the gel electrolyte according to claim 4, characterized in that, The molar ratio of the difunctional triacrylate to the polyethylene glycol diacrylate is 1:(0.25-4).

13. The method for preparing the gel electrolyte according to claim 4, characterized in that, In step (2), the mixing reaction is carried out in a second solvent; the second solvent includes DMF and / or dimethylacetamide.

14. The method for preparing the gel electrolyte according to claim 13, characterized in that, The molar ratio of the difunctional triacrylate to the second solvent is 1:(5-15).

15. The method for preparing the gel electrolyte according to claim 4, characterized in that, In step (2), the mixing reaction is carried out in the presence of a second catalyst, which includes dimethylphenylphosphine.

16. The method for preparing the gel electrolyte according to claim 15, characterized in that, The molar ratio of the difunctional triacrylate to the second catalyst is 1:(0.005-0.05).

17. A semi-solid-state battery, characterized in that, The gel electrolyte includes the gel electrolyte according to any one of claims 1-2 or the gel electrolyte obtained by the preparation method according to any one of claims 3-16.

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