CN-119786712-B - Modified polyethylene oxide solid electrolyte and preparation method and application thereof

Abstract

The invention provides a modified polyethylene oxide solid electrolyte and a preparation method and application thereof, wherein the preparation method comprises the following steps of (1) mixing polyethylene oxide, a reducing agent and a solvent to obtain a polyethylene oxide mixed solution; and (2) heating the polyethylene oxide mixed solution to a reaction temperature, and then respectively dropwise adding the initiator solution and the electronegative active monomer into the heated polyethylene oxide mixed solution to obtain the modified polyethylene oxide solid electrolyte. According to the invention, the polyethylene oxide is modified, a branched chain component is introduced, the intermolecular hydrogen bond action is destroyed, the crystallinity of the polyethylene oxide can be reduced, and the ionic conductivity of the polyethylene oxide is further improved.

Inventors

• WANG YU
• ZHU GUANGDONG
• CHEN ZHAN
• GUO YONGJIANG
• WU FENG
• ZANG BING

Assignees

• 上海宇昂水性新材料科技股份有限公司

Dates

Publication Date

20260508

Application Date

20241225

Claims (18)

1. 1. A method for preparing a modified polyethylene oxide solid electrolyte, which is characterized by comprising the following steps: (1) Mixing polyethylene oxide, a reducing agent and a solvent to obtain a polyethylene oxide mixed solution; (2) Heating the polyethylene oxide mixed solution to a reaction temperature, and respectively dripping an initiator solution and an electronegative active monomer into the heated polyethylene oxide mixed solution to obtain the modified polyethylene oxide solid electrolyte; the reducing agent in the step (1) comprises ascorbic acid and/or amine reducing agent; The electronegative active monomer in the step (2) comprises any one or a combination of at least two of methoxy polyethylene glycol acrylate monomer, vinyl pyrrolidone monomer or vinyl pyridine monomer.
2. 2. The method of claim 1, wherein the solvent of step (1) comprises a polar solvent.
3. 3. The method of claim 2, wherein the polar solvent comprises water and/or NMP.
4. 4. A method of preparing as claimed in claim 3 wherein the polar solvent is water.
5. 5. The method of claim 1, wherein the amine reducing agent comprises any one or a combination of at least two of N, N-dimethylaniline, N-dimethyl-p-toluidine, or diethylenetriamine.
6. 6. The preparation method of claim 1, wherein the mass ratio of the polyethylene oxide to the reducing agent in the step (1) is 1 (0.005-0.01).
7. 7. The method of claim 1, wherein the polyethylene oxide has a molecular weight of 1 x 10 5 ~1×10 6 .
8. 8. The preparation method according to claim 1, wherein the mass concentration of polyethylene oxide in the polyethylene oxide mixed solution in the step (1) is 10% -30%.
9. 9. The method of claim 1, wherein the initiator of step (2) comprises lithium perchlorate.
10. 10. The preparation method of claim 1, wherein the mass ratio of the polyethylene oxide in the polyethylene oxide mixed solution in the step (2) to the active monomer to the initiator in the initiator solution is 1 (0.2-0.4) (0.005-0.02).
11. 11. The method of claim 1, wherein the heating and dropping in step (2) is performed under a protective atmosphere.
12. 12. The method of claim 11, wherein the protective atmosphere comprises any one or a combination of at least two of nitrogen, argon, or helium.
13. 13. The method of claim 1, wherein the reaction temperature in step (2) is 35 ℃ to 60 ℃.
14. 14. The method of claim 1, wherein the time of the dropping in the step (2) is 3 to 8 hours.
15. 15. The method according to claim 1, wherein the dropping in step (2) is followed by a heat-retaining reaction and a vacuum drying treatment.
16. 16. The method of claim 15, wherein the incubation time is 2h to 3h.
17. 17. A modified polyethylene oxide solid electrolyte, characterized in that it is produced by the production method according to any one of claims 1 to 16.
18. 18. A solid state battery comprising the modified polyethylene oxide solid state electrolyte of claim 17.

Description

Modified polyethylene oxide solid electrolyte and preparation method and application thereof Technical Field The invention belongs to the technical field of battery materials, and relates to a modified polyethylene oxide solid electrolyte, a preparation method and application thereof. Background Polyethylene oxide (PEO) is the most studied solid electrolyte matrix due to its strong dissociation capability for lithium salts, excellent electrochemical stability, low glass transition temperature, good flexibility, etc. The PEO-based electrolyte has various forms such as a crystal region, an amorphous region and the like at room temperature, the molecular motion of the amorphous region in the PEO-based solid electrolyte is faster than that of the crystal region, li + is mainly transmitted through the motion of a polymer chain segment in the amorphous region, the ion conductivity mainly depends on the motion capability of the chain segment in the amorphous region, and the ion conduction mainly depends on the amorphous region. The polymer is mainly in a crystalline state in a temperature range below the glass transition temperature (Tg), and the lower the glass transition temperature is, the better the flexibility of the polymer chain is. Therefore, in order to achieve high ionic conductivity of PEO at room temperature, measures to reduce crystallinity and glass transition temperature of the polymer are generally adopted to accelerate polymer chain segment movement, and methods such as blending modification with other polymers, composite nanofiller and the like are adopted to change the characteristics. CN105355974a discloses a solid electrolyte and a preparation method thereof, which belong to the field of high polymer materials. The method comprises the steps of preparing a sulfonylurea polymer and a polyphenylene sulfone sulfonic acid polymer, carrying out condensation reaction on the sulfonylurea polymer and the polyphenylene sulfone sulfonic acid polymer to obtain a polysulfidyl sulfonylurea, carrying out condensation reaction on the polysulfidyl sulfonylurea and polyoxyethylene, carrying out ring-opening polymerization reaction on a product and epoxy resin to obtain a polysulfidyl sulfonylurea/polyoxyethylene cross-linked compound, dissolving the polysulfidyl sulfonylurea/polyoxyethylene cross-linked compound with chloroform, carrying out lithium ion exchange treatment on the polysulfidyl sulfonylurea/polyoxyethylene cross-linked compound with an acidic solution of lithium hydride, and carrying out lithium ion treatment on the polysulfidyl sulfonylurea/polyoxyethylene cross-linked compound with an ion exchange solution to obtain the solid electrolyte. CN111952662a discloses a deep frozen polyoxyethylene-based solid electrolyte, a preparation method and a lithium ion battery. The preparation method comprises the steps of dissolving polyethylene oxide and lithium salt in a solvent to obtain a solid electrolyte solution, removing the solvent from the solid electrolyte solution through drying treatment to obtain a polyethylene oxide-based solid electrolyte, sealing the polyethylene oxide-based solid electrolyte by adopting a heat conducting material to obtain a sealed polyethylene oxide-based solid electrolyte, heating the sealed polyethylene oxide-based solid electrolyte to melt the polyethylene oxide-based solid electrolyte, transferring the melted polyethylene oxide-based solid electrolyte to an environment with the temperature not higher than 0 ℃, freezing the melted polyethylene oxide-based solid electrolyte, and recovering the temperature to room temperature to obtain the deep frozen polyethylene oxide-based solid electrolyte. The above scheme improves the ionic conductivity of polyethylene by carrying out condensation reaction on polyethylene or deforming the polyethylene under extreme conditions, but the polyethylene obtained by the above scheme is easily influenced by external environment change, so that the polyethylene has poor environmental adaptability due to the change of the crystallization characteristics of the polyethylene. Disclosure of Invention The invention aims to provide a modified polyethylene oxide solid electrolyte, a preparation method and application thereof, the invention modifies polyethylene oxide, the branched component is introduced to destroy the intermolecular hydrogen bonding of the polyethylene oxide, so that the crystallinity of the polyethylene oxide can be reduced, and the ionic conductivity of the polyethylene oxide is further improved. In order to achieve the aim of the invention, the invention adopts the following technical scheme: in a first aspect, the present invention provides a method for preparing a modified polyethylene oxide solid electrolyte, the method comprising the steps of: (1) Mixing polyethylene oxide, a reducing agent and a solvent to obtain a polyethylene oxide mixed solution; (2) And heating the polyethylene oxide mixed solution to a reaction tempera