A kind of polyethylene oxide based electrolyte and its preparation method and application

Abstract

The invention provides a polyoxyethylene-based electrolyte and its preparation method and application. The polyoxyethylene-based electrolyte has a chemical structural formula as shown in formula I, wherein each Ar is independently phenyl or substituted by a sulfonic acid group phenyl, in all Ar, the substitution rate of sulfonic acid group is 1 / 36~1 / 12, and the sulfonic acid group is——SO3H‑M+, M+ is hydrogen ion or metal cation; R1 is C1~C10 An alkoxy group, R2 is a C1-C4 alkyl group, n is an integer of 10-800, m is an integer of 8-44, and x is 0.1-0.8. The solid electrolyte film comprising the polyoxyethylene-based electrolyte has good mechanical properties and electrical properties, and high lithium ion conductivity.

Description

technical field [0001] The invention belongs to the field of electrolyte materials for lithium-ion batteries, and more specifically relates to a polyoxyethylene-based electrolyte and its preparation method and application. Background technique [0002] The electrolyte material in lithium-ion batteries is an important factor affecting the safety and stability of the overall battery. The current mainstream liquid electrolyte is easy to corrode electrodes and decompose to produce flammable gas, which can cause serious safety accidents such as fire and explosion. Compared with liquid electrolytes, solid electrolytes (including inorganic ceramic electrolytes and organic polymer electrolytes) have better safety, durability, and ease of design. Among them, organic polymer solid electrolytes are more suitable for use in multi-modal batteries due to their low elastic modulus, simple preparation process and low cost, including all-solid polymer electrolytes and gel polymer electrolyt...

AI Technical Summary

Problems solved by technology

At present, polyethylene oxide (PEO-based) polymer electrolytes can basically meet the above-mentioned items (2) and (4). The PEO-based polymer electrolyte of the battery, due to the large molecular weight of the PEO used, is easy to crystallize at room temperature, so the transmission capacity of lithium ions decreases, and the room temperature conductivity of the electrolyte is only 10. -6 S / cm, so there is still a certain gap from practicality

[0004] At present, the following methods are commonly used to improve the ionic conductivity and lithium ion mobility of PEO-based polymer electrolyte materials: (1) Adding plasticizers can greatly increase the conductivity, which is simple to prepare and cheap; but it will lead to a decline in mechanical properties, and Compatibility and stability between components will decrease

(2) Adding ionic liquid can improve electrical conductivity, non-flammability, low vapor pressure, and good thermochemical and electrochemical stability; but the mechanical properties decrease, and the ion mobility does not increase significantly.

and expensive

(3) Adding nanoparticles, taking into account the electrical conductivity and mechanical properties, the price is cheap, and the safety is high; but it still cannot meet the commercial requirements

(4) Block copolymerization, which not only improves electrical conductivity and ion mobility, but also ensures better mechanical properties; for example, patent document CN104684949A discloses a multi-block copolymer and polymer electrolyte, but its melting temperature is higher , the highest room temperature conductivity is only 1.9×10- 5 S / cm, and the preparation process of this compound is also relatively complicated

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