PEO-based solid polymer electrolyte composite material and preparation method thereof

Abstract

The invention discloses a PEO-based solid polymer electrolyte composite material and a preparation method thereof. The PEO-based solid polymer electrolyte composite material comprises, by mass, 5-80%of polyoxyethylene, 2-80% of a high molecular polymer and 1-30% of a lithium salt. The preparation method comprises the following steps: A, adding the lithium salt to an organic solvent, and performing stirring until the lithium salt is completely dissolved; B, adding the high molecular polymer to a solution prepared in step A, and performing uniform stirring; C, adding the polyoxyethylene to a uniform mixed solution prepared in step B, and performing stirring to obtain a uniform suspension; and D, pouring the suspension prepared in step C poured into a mold, and drying the suspension to obtain the solid electrolyte material. The high molecular polymer in the PEO-based solid polymer electrolyte composite material effectively inhibits the crystallization of an oxyethylene chain in the polyoxyethylene, so the electrical conductivity of the solid polymer electrolyte is effectively increased.

Description

[technical field] [0001] The invention relates to a lithium ion battery, in particular to a PEO-based solid polymer electrolyte composite material and a preparation method thereof. [Background technique] [0002] With the rapid development of mobile electronic devices, electric vehicles, and grid energy storage systems, the performance and management systems of lithium-ion batteries are increasingly demanding. Electrolyte is an indispensable part of lithium-ion batteries. It plays the role of transporting ions at the positive and negative electrodes, and is also closely related to the performance of lithium-ion batteries. At present, the electrolyte in lithium-ion batteries is generally an organic liquid electrolyte, but safety problems caused by leakage and combustion of the electrolyte in lithium-ion batteries are common, which limits its large-scale application in the field of chemical energy storage. While the capacity, rate performance, and cycle stability of lithium-i...

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Problems solved by technology

Since the migration of lithium ions is mainly carried out in the amorphous region of the polymer, and PEO is easy to crystallize, the solubility of lithium salts in the amorphous phase is low, the number of carriers is small, and the migration number of lithium ions is low, so it is compatible with liquid electrolytes. Compared with PEO-based polymer electrolyte, its conductivity at room temperature or below room temperature is low, at 10 -6 Below the order of S / cm, the application of pure PEO polymer electrolyte is limited

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