Application of carboxymethyl chitosan self-crosslinking polymer in silicon negative electrode of lithium ion battery

Abstract

The invention discloses an application of a carboxymethyl chitosan self-crosslinking polymer in a silicon negative electrode of a lithium ion battery. The carboxymethyl chitosan self-crosslinking polymer is obtained by adding carboxymethyl chitosan to cross-liking agent 1-(3-(dimethylamino propyl)-3-ethyl-carbodiimide hydrochloride in a self-crosslinking manner; the polymer has a three-dimensional structure, and is taken as a binder to be applied to preparation of the silicon negative electrode of the lithium ion battery; the self-crosslinking polymer shows high mechanical performance and adhesive property; chemical bonds with self-repairing capability are formed between the self-crosslinking polymer and the silicon particles; the silicon negative electrode with large volume change in the charging-discharging process can be effectively accommodated; the powder-fall-off phenomenon with structural damage caused by severe volume changes of the silicon particles in the circulating process of the silicon negative electrode is solved; and a new approach for improving the cycle performance of the silicon negative electrode of the lithium ion battery is provided.

Description

technical field [0001] The invention relates to the application of a carboxymethyl chitosan self-crosslinking polymer as a silicon negative electrode binder in lithium ion batteries, in particular to the preparation of a modified biological natural polymer binder and its application in lithium batteries The application in the silicon negative electrode relates to the technical field of lithium batteries. Background technique [0002] With the development of portable electronic devices and electric vehicles, people's requirements for the energy density of lithium batteries are also increasing. In order to increase the energy density of lithium batteries, the performance of each component (positive electrode, negative electrode, electrolyte and separator) needs to be improved. In terms of negative electrode materials, the traditional negative electrode material graphite due to its low theoretical capacity (372mAhg -1 ) can no longer meet the requirements of high energy densi...

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Problems solved by technology

[0012] Aiming at the problems of poor bonding performance, complex preparation process and poor self-repairing function of the polymer binder in the prior art, which cannot meet the application requirements of the existing lithium battery silicon negative electrode material, the purpose of the present invention is to provide a The application of carboxymethyl chitosan self-crosslinking polymer with three-dimensional structure, the crosslinked polymer exhibits good mechanical properties, bonding properties and chemical bond self-healing ability, can effectively solve the problem of silicon anode in the cycle process. Structural damage of particles due to drastic volume changes

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