PEO-based gel polymer electrolyte and preparation method thereof

Abstract

The invention belongs to the field of electrolytes and discloses a PEO-based gel polymer electrolyte and a preparation method thereof. The PEO-based gel polymer electrolyte comprises a PEO matrix, a LiBF4 / PC+DMC lithium salt and a titanate, wherein a mole ratio of LiBF4 to the titanate is 1: 0.001 to 1: 0.05. The titanate of the PEO-based gel polymer electrolyte can adsorb BF4<-> and form a coordination compound so that a LiBF4 dissociation degree is improved and lithium ion transport number is increased and thus conductivity is greatly improved. In a lithium ion battery, the PEO-based gel polymer electrolyte cannot be leaked, has good safety and greatly improves conductivity.

Description

technical field [0001] The invention relates to the field of electrolytes, in particular to a PEO matrix gel polymer electrolyte and a preparation method thereof. Background technique [0002] Safety issues are the bottleneck restricting the application of high-capacity and high-power lithium-ion batteries. The main safety hazards of batteries are the combustion and explosion caused by leakage of liquid electrolyte, electrolyte oxidation decomposition and thermal runaway, which are widely used at present. Gel polymer electrolyte lithium-ion batteries have been valued by researchers because of their safety, no leakage, and low leakage current. And the gel polymer electrolyte is a new type of functional polymer material, which can be used as a diaphragm and an electrolyte material at the same time, which can make the battery thinner, thereby improving the flexibility of the battery design. [0003] PEO has the advantages of easy processing and good thermoplasticity of solid ...

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Problems solved by technology

[0004] Lithium trifluoroacetate (LiCF 3 CO 2 ) Because of the low cost of raw materials and good compatibility with organic polymers, it is one of the more promising lithium salts for gel electrolytes. However, PEO-based gel polymer electrolytes containing lithium trifluoroacetate are in Impurities (water) will inevitably be contained in the preparation process. During the electrochemical cycle, water will participate in the electrode reaction to generate acid, which will corrode the aluminum foil of the electric double layer capacitor, resulting in the use of LiCF 3 CO 2 Decreased stability of electric double layer capacitors with PEO-based gel polymer electrolyte as electrolyte

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