Hyperbranched polyester lithium ion battery gel electrolyte and preparation method thereof

Abstract

The invention relates to a hyperbranched polyester lithium ion battery gel electrolyte and a preparation method thereof. The gel electrolyte is formed by mixed liquor prepared from 5-30 percent by mass of hyperbranched photopolymer resin, 5-25 percent by mass of cross-linking agent, 1-10 percent by mass of initiator, 20-50 percent by mass of plasticizer, 20-50 percent by mass of lithium salt and the like by using a radiation crosslinking method or a heating crosslinking method and the like. In the invention, the hyperbranched structure of a hyperbranched polyester can effectively prevent chain segments from being crystallized, whereas the molecular conformation similar to a spheric shape can increase the free volume of the polyester; bigger space and fewer -COO- and ether bond structures among branch points of the hyperbranched polyester have very strong interreaction with oxygen in the carbonic ester plasticizer, and therefore, a large amount of liquid electrolyte can be contained, and the gel electrolyte has very high dissolving capacity on salts, which is beneficial to ionic migration and the increase of electrical conductivity so that a lithium ion battery prepared from the hyperbranched polyester lithium ion battery gel electrolyte has long service life, small internal resistance, better specific energy, simple preparation process and no pollution.

Description

technical field The present invention relates to gel electrolytes for lithium ion batteries, in particular hyperbranched polyester lithium for lithium ion batteries with high ionic conductivity, suitable mechanical strength, flexibility, pore structure and chemical and electrochemical stability Ion battery gel electrolyte and preparation method thereof. Background technique The technical core of the polymer lithium-ion battery is to use the polymer matrix as the skeleton structure of the electrode and the electrolyte, and the liquid electrolyte molecules are fixed in it, so that the electrodes and the electrolyte have high ionic conductivity inside. The key technology of polymer lithium-ion batteries is the preparation of polymer electrolytes, which require high ionic conductivity, suitable mechanical strength, flexibility, and chemical and electrochemical stability. The development of polymer matrix, that is, solid electrolyte, can be roughly divided into three stages: ① ...

AI Technical Summary

Problems solved by technology

Because the polyacrylonitrile chain contains a strong polar group -CN, it has poor compatibility with metal lithium electrodes, and the interface passivation between the gel electrolyte membrane and lithium electrodes is serious.

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