A solid electrolyte and a battery

Abstract

The present invention provides a solid electrolyte and a battery. The solid electrolyte includes a multi - copolymer and a modified electrolyte. The multi - copolymer includes a cyano structural unit, an organic acid structural unit, and an acrylate structural unit; the modified electrolyte includes electrolyte particles and polydopamine located on the surface of the electrolyte particles. The solid electrolyte provided in this application makes the modified electrolyte negatively charged by coating a polydopamine coating on the surface of the electrolyte particles, avoiding the aggregation of the modified electrolyte in the multi - copolymer. Hydrogen bonds are formed between N, O and active hydrogen in the polydopamine coating and the multi - copolymer, improving the binding force between the multi - copolymer and the modified electrolyte.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and particularly relates to a solid electrolyte and a battery. Background Art

[0002] Since commercialization, lithium-ion batteries have been widely used in fields such as portable electronic devices and electric vehicles. A series of problems currently caused by liquid electrolytes, such as electrode dissolution, side reactions of electrodes, growth of lithium dendrites, and poor thermal stability, have made lithium-ion batteries with higher energy density, longer cycle life, and higher safety an urgent need in the current market. The solid electrolytes used in solid-state batteries, which have a wide electrochemical stability window, high modulus, and high thermal stability, have the potential to match high-capacity electrode materials, inhibit the growth of lithium dendrites, and improve the safety of use. At the same time, all-solid-state batteries using a lithium metal anode can achieve higher energy density. Therefore, the technology of solid-state lithium-ion batteries has good development prospects.

[0003] The realization of excellent electrochemical performance of all-solid-state lithium-ion batteries requires its core - the solid electrolyte to have high ionic conductivity and excellent electrolyte / electrode interface contact. Solid polymer electrolytes have good flexibility and excellent contact with the positive electrode, but their ionic conductivity is low and their mechanical strength is insufficient to inhibit the growth of lithium dendrites. Currently, by adding inorganic ceramic fillers to solid polymer electrolytes, both higher ionic conductivity (10 -4 S / cm) and the advantages of the flexibility of polymers and better interface contact are retained. However, currently, the interface contact between polymers and inorganic ceramic particles in composite polymer electrolytes is poor, and the dispersion of inorganic ceramic particles in polymers is poor, resulting in generally low ionic conductivity of composite solid electrolytes, and uneven distribution of the ionic conductivity and strength of the electrolytes, ultimately affecting the performance of the assembled battery. Summary of the Invention

[0004] Aiming at the technical problems of poor interface contact between polymers and inorganic ceramic particles and poor dispersion of inorganic ceramic particles in composite polymer solid electrolytes in the prior art, the present invention provides a solid electrolyte and a battery.

[0005] To solve the above technical problems, on the one hand, the present invention provides a solid electrolyte, the solid electrolyte comprising a multi-block copolymer and a modified electrolyte, the multi-block copolymer comprising a cyano structural unit, an organic acid structural unit, and an acrylate structural unit;

[0006] The modified electrolyte comprises electrolyte particles and polydopamine on the surface of the electrolyte particles.

[0007] Preferably, the mass ratio of the multi-block copolymer to the modified electrolyte is (20~60):(40~80).

[0008] Preferably, the mass ratio of the cyano structural unit, the organic acid structural unit, and the acrylate structural unit is (50-70):(10-30):(20-40).

[0009] Preferably, the organic acid structural unit is a sulfonic acid structural unit; the sulfonic acid structural unit is selected from at least one of an olefin sulfonic acid structural unit having 2-14 carbon atoms, a styrene sulfonic acid structural unit, a styrene sulfonic acid alkyl derivative structural unit, an acrylic acid sulfo-hydroxyalkyl ester structural unit having 5-18 carbon atoms, a methacrylic acid sulfo-hydroxyalkyl ester structural unit having 5-18 carbon atoms, a sulfoalkyl methacrylamide structural unit having 5-18 carbon atoms, and an alkyl allyl sulfosuccinic acid structural unit having 3-18 carbon atoms.

[0010] Preferably, the cyano structural unit is selected from one or more of an acrylonitrile structural unit, a styrene cyanide structural unit, a methacrylonitrile structural unit, an ethyl acrylonitrile structural unit, a propyl acrylonitrile structural unit, a 2-cyano-3-ethoxyethyl acrylate structural unit, a cyanoethyl acrylate structural unit, a tetrakis(4-cyanophenyl)ethylene structural unit, a 2-cyano-5-norbornene structural unit, and a benzyl malononitrile structural unit;

[0011] The acrylate structural unit is selected from at least one of a methyl acrylate structural unit, an ethyl acrylate structural unit, a n-propyl acrylate structural unit, an isopropyl acrylate structural unit, a n-butyl acrylate structural unit, an isobutyl acrylate structural unit, a tert-butyl acrylate structural unit, a n-pentyl acrylate structural unit, an isopentyl acrylate structural unit, a n-hexyl acrylate structural unit, a n-octyl acrylate structural unit, an isooctyl acrylate structural unit, an isobornyl acrylate structural unit, a phenoxyethyl acrylate structural unit, a dicyclopentenyl acrylate structural unit, a cyclohexyl acrylate structural unit, a benzyl acrylate structural unit, a methyl methacrylate structural unit, an ethyl methacrylate structural unit, a n-propyl methacrylate structural unit, an isopropyl methacrylate structural unit, a n-butyl methacrylate structural unit, an isobutyl methacrylate structural unit, a tert-butyl methacrylate structural unit, a n-pentyl methacrylate structural unit, an isopentyl methacrylate structural unit, a n-hexyl methacrylate structural unit, an isooctyl methacrylate structural unit, an isobornyl methacrylate structural unit, a phenoxyethyl methacrylate structural unit, a dicyclopentenyl methacrylate structural unit, a cyclohexyl methacrylate structural unit, a benzyl methacrylate structural unit, an ethylene glycol diacrylate structural unit, an ethylene glycol dimethacrylate structural unit, an ethoxylated ethylene glycol diacrylate structural unit, an ethoxylated ethylene glycol dimethacrylate structural unit, an allyl methacrylate structural unit, a diallyl phthalate structural unit, a diallyl adipate structural unit, a trimethylolpropane triacrylate structural unit, a trimethylolpropane trimethacrylate structural unit, a pentaerythritol diacrylate structural unit, a pentaerythritol dimethacrylate structural unit, a pentaerythritol triacrylate structural unit, and a pentaerythritol trimethacrylate structural unit.

[0012] Preferably, the mass ratio of the polydopamine to the electrolyte particles is (5 - 30):(70 - 95).

[0013] Preferably, the polydopamine coats the surface of the electrolyte particles to form a polydopamine coating layer, and the thickness of the polydopamine coating layer is 5 - 30 nm.

[0014] Preferably, the volume average particle size D50 of the electrolyte particles is 0.3 - 3 μm.

[0015] Preferably, the electrolyte particles include one or more of LLTO, LLZO, and LAGP.

[0016] On the other hand, the present application provides a battery, including a negative electrode, a positive electrode, and the solid electrolyte as described in any one of the above.

[0017] The solid electrolyte provided by this application forms a coating layer on the surface of electrolyte particles by using polydopamine due to its adhesiveness. Its structure makes the electrolyte particles negatively charged, and the strong electrostatic repulsion makes the polydopamine-coated electrolyte particles exhibit extremely high stability, avoiding agglomeration when the modified electrolyte particles are compounded with the copolymer, enabling the modified electrolyte to be evenly dispersed in the copolymer, ensuring the uniformity and consistency of the strength of the solid electrolyte, and obtaining a composite polymer solid electrolyte. Hydrogen bonds are formed between N, O and active hydrogen in the polydopamine coating layer and the copolymer, improving the binding force between the copolymer and the modified electrolyte and ensuring the binding strength between the electrolyte particles and the polymer. The chain segments of polydopamine have flexibility, improving the interfacial contact with the copolymer and reducing the interfacial resistance. The flexibility of the copolymer is improved by introducing acrylate structural units. The antioxidant property of the copolymer is improved by introducing cyano structural units to match the high-voltage cathode material. By introducing structural units containing organic acid classes into the copolymer, electronegative groups are carried on the main chain of the copolymer, providing a stable transport channel for lithium ions. Under the action of an electric field, lithium ions migrate through the mechanism of hopping transmission between adjacent organic acid radical groups on the chain segments of the copolymer, strengthening ion transport and facilitating the improvement of the ionic conductivity of the solid electrolyte. Detailed implementation manners

[0018] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the following further describes the present invention in detail with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] An embodiment of this application provides a solid electrolyte, which includes a copolymer and a modified electrolyte. The copolymer includes a cyano structural unit, an organic acid class structural unit and an acrylate structural unit;

[0020] The modified electrolyte includes electrolyte particles and polydopamine located on the surface of the electrolyte particles.

[0021] The solid electrolyte provided in this embodiment makes the modified electrolyte negatively charged by coating a polydopamine coating layer on the surface of the electrolyte particles, avoiding the agglomeration of the modified electrolyte in the copolymer, enabling the modified electrolyte to be uniformly dispersed in the copolymer, and ensuring the uniformity and consistency of the strength of the solid electrolyte. Hydrogen bonds are formed between N, O, and active hydrogen in the polydopamine coating layer and the copolymer, improving the binding force between the copolymer and the modified electrolyte. The segments of polydopamine have flexibility, improving the interfacial contact with the copolymer. The flexibility of the copolymer is improved by introducing acrylate structural units. The antioxidant property of the copolymer is enhanced by introducing cyano structural units, which is suitable for high-voltage cathode materials. By introducing organic acid structural units into the copolymer, electronegative groups are carried on the main chain of the copolymer, providing a stable transmission channel for lithium ions. Under the action of an electric field, lithium ions migrate through the mechanism of hopping between adjacent organic acid root groups on the segments of the copolymer, strengthening ion transport and facilitating the improvement of the ionic conductivity of the solid electrolyte. Moreover, the solid electrolyte in this embodiment can have a high ionic conductivity without adding a lithium salt.

[0022] In some embodiments, the mass ratio of the copolymer to the modified electrolyte is (20~60):(40~80). By controlling the mass ratio of the copolymer to the modified electrolyte, the ionic conductivity and mechanical strength of the solid electrolyte are improved.

[0023] Specifically, the mass ratio of the modified electrolyte to the copolymer includes but is not limited to 40:60, 50:50, 65:35, 70:30, 75:25, or 80:20.

[0024] In some embodiments, the mass ratio of the cyano structural unit, the organic acid structural unit, and the acrylate structural unit is (50~70):(10~30):(20~40). By controlling the mass ratio of each structural unit, the antioxidant property and flexibility of the copolymer are regulated.

[0025] Specifically, the mass ratio of the cyano structural unit, the organic acid structural unit, and the acrylate structural unit includes but is not limited to 50:20:30, 60:20:20, 60:10:30, 65:15:20, 70:10:20. In the present invention, the mass ratio of the above structural units is based on the mass ratio between the raw material monomers corresponding to each structural unit when participating in the polymerization to obtain the copolymer.

[0026] In some embodiments, the cyano structural unit is a structural unit obtained by the polymerization of a cyano-containing monomer, and the cyano structural unit is selected from acrylonitrile structural unit, styrene cyanide structural unit, methacrylonitrile structural unit, ethylacrylonitrile structural unit, propylacrylonitrile structural unit, 2-cyano-3-ethoxyethyl acrylate structural unit, ethyl cyanoacrylate structural unit, tetrakis(4-cyanophenyl)ethylene structural unit, 2-cyano-5-norbornene structural unit, benzylmalononitrile structural unit, or one or more thereof.

[0027] In some embodiments, the organic acid structural unit is preferably a sulfonic acid structural unit, specifically a structural unit obtained by the polymerization of a monomer containing a sulfonic acid group. The sulfonic acid structural unit is selected from C2-C14 olefin sulfonic acid structural units (such as vinyl sulfonic acid structural unit, methallyl sulfonic acid structural unit, allyl sulfonic acid structural unit, methyl vinyl sulfonic acid structural unit), styrene sulfonic acid structural units, styrene sulfonic acid alkyl derivative structural units (the alkyl may have 2-24 carbon atoms, such as α-methylstyrene sulfonic acid structural unit), C5-C18 acrylic acid sulfohydroxyalkyl ester structural units, C5-C18 methacrylic acid sulfohydroxyalkyl ester structural units (such as methacrylic acid sulfopropyl ester structural unit, 2-hydroxy-3-methacryloyloxypropyl sulfonic acid structural unit, 2-methacryloyloxyethane sulfonic acid structural unit, 3-methacryloyloxy-2-hydroxypropane sulfonic acid structural unit), C5-C18 sulfopropyl methacrylamide structural units (such as 2-methacrylamido-2,2-dimethylethane sulfonic acid structural unit, 2-methacrylamido-2-methylpropane sulfonic acid structural unit, 2-acrylamido-2-methylpropane sulfonic acid structural unit, 3-methacrylamido-2-hydroxypropane sulfonic acid structural unit), C3-C18 alkyl allyl sulfosuccinate structural units (such as propyl allyl sulfosuccinate structural unit, butyl allyl sulfosuccinate structural unit, 2-ethylhexyl-allyl sulfosuccinate structural unit), or at least one of them. More preferably, the sulfonic acid structural unit is 2-acrylamido-2-methylpropane sulfonic acid structural unit.

[0028] In some embodiments, the acrylate structural unit is a structural unit obtained by the polymerization of acrylate monomers, and the acrylate structural unit is selected from methyl acrylate structural unit, ethyl acrylate structural unit, n-propyl acrylate structural unit, isopropyl acrylate structural unit, n-butyl acrylate structural unit, isobutyl acrylate structural unit, tert-butyl acrylate structural unit, n-pentyl acrylate structural unit, isopentyl acrylate structural unit, n-hexyl acrylate structural unit, n-octyl acrylate structural unit, isooctyl acrylate structural unit, isobornyl acrylate structural unit, phenoxyethyl acrylate structural unit, dicyclopentenyl acrylate structural unit, cyclohexyl acrylate structural unit, benzyl acrylate structural unit, methyl methacrylate structural unit, ethyl methacrylate structural unit, n-propyl methacrylate structural unit, isopropyl methacrylate structural unit, n-butyl methacrylate structural unit, isobutyl methacrylate structural unit, tert-butyl methacrylate structural unit, n-pentyl methacrylate structural unit, isopentyl methacrylate structural unit, n-hexyl methacrylate structural unit, isooctyl methacrylate structural unit, isobornyl methacrylate structural unit, phenoxyethyl methacrylate structural unit, dicyclopentenyl methacrylate structural unit, cyclohexyl methacrylate structural unit, benzyl methacrylate structural unit, ethylene glycol diacrylate structural unit, ethylene glycol dimethacrylate structural unit, ethoxylated ethylene glycol diacrylate structural unit, ethoxylated ethylene glycol dimethacrylate structural unit, allyl methacrylate structural unit, diallyl phthalate structural unit, diallyl adipate structural unit, trimethylolpropane triacrylate structural unit, trimethylolpropane trimethacrylate structural unit, pentaerythritol diacrylate structural unit, pentaerythritol dimethacrylate structural unit, pentaerythritol triacrylate structural unit, pentaerythritol trimethacrylate structural unit, or at least one of them.

[0029] Preferably, the polydopamine is coated on the surface of the electrolyte particles to form a polydopamine coating layer.

[0030] In some embodiments, the mass ratio of the polydopamine to the electrolyte particles is (5~30):(70~95). By controlling the mass ratio of the polydopamine to the electrolyte particles, it is ensured that the electrolyte particles are completely coated, and at the same time, the final particle size of the modified electrolyte is controlled.

[0031] Specifically, the mass ratio of the polydopamine to the electrolyte particles includes but is not limited to 5:95, 10:90, 20:80, 15:85, 25:75 or 30:70.

[0032] In some embodiments, the thickness of the polydopamine coating layer is 5 to 30 nm. The thickness of the polydopamine coating layer on the surface of the above electrolyte particles can be measured by scanning electron microscopy (SEM).

[0033] In some embodiments, the volume average particle size D50 of the electrolyte particles is 0.3 to 3 μm.

[0034] In some embodiments, the electrolyte particles include one or more of LLTO, LLZO, and LAGP. The above electrolyte particles can be directly obtained by commercial purchase. When purchasing, directly select the electrolyte particles with the required volume average particle size D50.

[0035] Specifically, the preparation method of the solid electrolyte includes the following steps:

[0036] Mix a cyano monomer, an organic acid monomer, and an acrylate monomer, and prepare a copolymer by emulsion polymerization in the presence of an initiator. The above specific operations are known to those skilled in the art and will not be elaborated in the present invention.

[0037] Use polydopamine (PDA) to mill and coat the electrolyte particles by high-energy ball milling to obtain modified electrolytes.

[0038] It should be noted that if polydopamine (PDA) is first mixed with the copolymer and then the mixture is mixed with the electrolyte particles, polydopamine cannot adhere to the surface of the electrolyte particles and further form the above coating layer, and thus the object of the present invention cannot be achieved.

[0039] Mix the copolymer and the modified electrolyte in a certain proportion, and obtain a mixed slurry of the composite electrolyte after dispersion. Use the coating and casting method to coat the composite solid electrolyte slurry on a release film, and obtain a solid electrolyte after drying.

[0040] Among them, polydopamine has polar groups, has wettability and strong adhesion to inorganic electrolyte particles, can coat the inorganic electrolyte particles to form a "nano coat", and its structure makes the modified electrolyte negatively charged. The strong electrostatic repulsive force makes the electrolyte particles wrapped by PDA exhibit extremely strong stability. The connection between the benzene ring and the functional groups on the main chain of PDA makes the main chain of PDA show a certain flexibility.

[0041] An embodiment of the present application provides a battery, including a negative electrode, a positive electrode, and the solid electrolyte described in any one of the above embodiments.

[0042] The present invention will be further described below through examples.

[0043] Specifically illustrate the solid electrolyte and its battery disclosed in the present invention.

[0044] Example 1

[0045] Solid-state electrolyte

[0046] Acrylonitrile, 2-acrylamido-2-methylpropanesulfonic acid, and ethyl acrylate were mixed in a mass ratio of 60:15:25, and then a copolymer was prepared by emulsion polymerization.

[0047] LLTO was ball-milled and coated with polydopamine (PDA) by high-energy ball milling to obtain a modified electrolyte.

[0048] The copolymer and the modified electrolyte were mixed in a mass ratio of 20:80, and after dispersion, a mixed slurry of composite electrolyte was obtained. The composite solid-state electrolyte slurry was coated on a release film by a casting method, and then dried to obtain a solid-state electrolyte.

[0049] Preparation of the negative electrode sheet

[0050] A lithium sheet was selected as the negative electrode sheet.

[0051] Preparation of the positive electrode sheet

[0052] ]>The positive active material high-nickel ternary (NCM811), conductive carbon black, and positive electrode binder were mixed in a mass ratio of 90:3:7, and NMP was added to make a positive electrode slurry. The positive electrode slurry was coated on an aluminum foil and dried to obtain a positive electrode sheet.

[0053] Battery preparation

[0054] The negative electrode sheet, the positive electrode sheet, and the solid-state electrolyte were assembled into a battery.

[0055] Examples 2 to 19

[0056] Examples 2 to 19 and Example 1 have most of the same steps, the difference is that the formulations in Table 1 and Table 2 are adopted.

[0057] Comparative Examples 1 to 4

[0058] Comparative Examples 1 to 4 and Example 1 have most of the same steps, the difference is that the formulations in Table 1 and Table 2 are adopted.

[0059] Table 1

[0060]

[0061] Table 2

[0062]

[0063] Electrical performance test: <?

[0064] The solid electrolytes and batteries prepared in the above examples and comparative examples were tested as follows.

[0065] 1. Ionic conductivity: Replace the positive and negative electrode sheets in the preparation method of the all-solid-state lithium-ion battery with two stainless steel foil sheets as blocking electrodes, and use the AC impedance test of the Shanghai Chenhua electrochemical workstation. Set the frequency range to 0.1 - 1 MHz and the amplitude to 10 mV to conduct the ionic conductivity test at room temperature (30 °C).

[0066] 2. Test of mechanical properties: The mechanical properties of the solid electrolyte were characterized by stress-stretching test. Before the test, dehumidify the environment where the instrument is located, control the environmental temperature at 25 °C, cut the solid electrolyte to be tested into a size of 50 mm in length and 10 mm in width, set the stretching speed to 6 mm / min, and the clamping distance to 20 mm.

[0067] 3. Capacity retention rate test: Perform constant current charge and discharge on the all-solid-state lithium-ion battery at a current density of 0.2C at 60 °C within 2.8 - 4.0 V, test the initial discharge specific capacity and the discharge specific capacity after 500 cycles, and calculate the capacity retention rate.

[0068] The test results are shown in Table 3 below.

[0069] Table 3

[0070]

[0071] It can be seen from the above test results that the solid electrolyte provided by the present invention has excellent ionic conductivity and tensile strength, and can effectively improve the cycle capacity retention rate of the solid battery.

[0072] From the test results of Example 1 and Comparative Example 4, it can be seen that by coating a polydopamine layer on the surface of the electrolyte particles, the ionic conductivity and tensile strength of the solid electrolyte are significantly higher than those of Comparative Example 4, and the cycle life of the battery is also significantly improved, further proving that there is a good synergistic effect between the polydopamine coating layer and the copolymer.

[0073] From the test results of Example 1 and Comparative Examples 1 - 3, it can be seen that the copolymer contains a cyano structural unit, an organic acid structural unit, and an acrylate structural unit at the same time, which makes the solid electrolyte have good ionic conductivity and tensile strength.

[0074] From the test results of Examples 1 - 13, it can be seen that when the mass ratio of the cyano structural unit, the organic acid structural unit, and the acrylate structural unit in the copolymer is in the range of (50 - 70):(10 - 30):(20 - 40), the solid electrolyte has good ionic conductivity and tensile strength.

[0075] As can be seen from the test results of Examples 16 to 19, when the mass ratio of the multi-component copolymer to the modified electrolyte is in the range of (20 to 60):(40 to 80), the solid electrolyte has good ionic conductivity and tensile strength.

[0076] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A solid electrolyte, characterized in that, The solid electrolyte includes a multi-component copolymer and a modified electrolyte, and the mass ratio of the multi-component copolymer to the modified electrolyte is (20-60):(40-80); the multi-component copolymer includes a cyano structural unit, an organic acid structural unit, and an acrylate structural unit; the mass ratio of the cyano structural unit, the organic acid structural unit, and the acrylate structural unit is (50-70):(10-30):(20-40); The modified electrolyte includes electrolyte particles and polydopamine located on the surface of the electrolyte particles; The solid electrolyte does not contain a lithium salt.

2. The solid electrolyte according to claim 1, characterized in that, The organic acid structural unit is a sulfonic acid structural unit; The sulfonic acid structural unit is selected from at least one of olefin sulfonic acid structural units with C2-C14, styrene sulfonic acid structural units, styrene sulfonic acid alkyl derivative structural units, acrylate sulfohydroxyalkyl ester structural units with C5-C18, methacrylate sulfohydroxyalkyl ester structural units with C5-C18, sulfopropyl methacrylamide structural units with C5-C18, and alkyl allyl sulfosuccinic acid structural units with C3-C18.

3. The solid electrolyte according to claim 1, wherein The cyano structural unit is selected from one or more of acrylonitrile structural units, styrene cyanide structural units, methacrylonitrile structural units, ethyl acrylonitrile structural units, propyl acrylonitrile structural units, 2-cyano-3-ethoxyethyl acrylate structural units, ethyl cyanoacrylate structural units, tetra(4-cyanophenyl)ethylene structural units, 2-cyano-5-norbornene structural units, and benzyl malononitrile structural units; The acrylate structural unit is selected from at least one of a methyl acrylate structural unit, an ethyl acrylate structural unit, a n-propyl acrylate structural unit, an isopropyl acrylate structural unit, a n-butyl acrylate structural unit, an isobutyl acrylate structural unit, a tert-butyl acrylate structural unit, a n-pentyl acrylate structural unit, an isopentyl acrylate structural unit, a n-hexyl acrylate structural unit, a n-octyl acrylate structural unit, an isooctyl acrylate structural unit, an isobornyl acrylate structural unit, a phenoxyethyl acrylate structural unit, a dicyclopentenyl acrylate structural unit, a cyclohexyl acrylate structural unit, a benzyl acrylate structural unit, a methyl methacrylate structural unit, an ethyl methacrylate structural unit, a n-propyl methacrylate structural unit, an isopropyl methacrylate structural unit, a n-butyl methacrylate structural unit, an isobutyl methacrylate structural unit, a tert-butyl methacrylate structural unit, a n-pentyl methacrylate structural unit, an isopentyl methacrylate structural unit, a n-hexyl methacrylate structural unit, an isooctyl methacrylate structural unit, an isobornyl methacrylate structural unit, a phenoxyethyl methacrylate structural unit, a dicyclopentenyl methacrylate structural unit, a cyclohexyl methacrylate structural unit, a benzyl methacrylate structural unit, an ethylene glycol diacrylate structural unit, an ethylene glycol dimethacrylate structural unit, an ethoxylated ethylene glycol diacrylate structural unit, an ethoxylated ethylene glycol dimethacrylate structural unit, an allyl methacrylate structural unit, a diallyl phthalate structural unit, a diallyl adipate structural unit, a trimethylolpropane triacrylate structural unit, a trimethylolpropane trimethacrylate structural unit, a pentaerythritol diacrylate structural unit, a pentaerythritol dimethacrylate structural unit, a pentaerythritol triacrylate structural unit, and a pentaerythritol trimethacrylate structural unit.

4. The solid electrolyte according to claim 1, characterized in that, The mass ratio of the polydopamine to the electrolyte particles is (5~30):(70~95).

5. The solid electrolyte according to claim 1, characterized in that, The polydopamine is coated on the surface of the electrolyte particles to form a polydopamine coating layer, and the thickness of the polydopamine coating layer is 5~30 nm.

6. The solid electrolyte according to claim 1, characterized in that The volume average particle size D50 of the electrolyte particles is 0.3~3 μm.

7. The solid electrolyte according to claim 1, characterized in that, The electrolyte particles include one or more of LLTO, LLZO, and LAGP.

8. A battery, characterized in that, [[ID=as=5]]It includes a negative electrode, a positive electrode, and the solid electrolyte according to any one of claims 1~7.

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