In-situ cross-linked polymer binding agent for lithium ion battery and electrode prepared from same

Abstract

The invention discloses an in-situ cross-linked polymer binding agent for a lithium ion battery and an electrode prepared from the in-situ cross-linked polymer binding agent. The polymer binding agent is of a three-dimensional network structure and is formed through in-situ polymerization of chitosan, at least one of polymers containing a carboxyl group or a carboxylate group, and at least one of micromolecule polybasic carboxylic acid and micromolecule polybasic carboxylate. An amidogen group on a chitosan molecular chain and a carboxyl group of the other polymer form a three-dimensional network structure in situ through electrostatic interaction at the room temperature, and dispersion uniformity of active materials in the electrode is improved. When the polymer binding agent is in use, a pole piece is subjected to further heat treatment, the cross-linking effect of the polymer chains is enhanced, and the stability of the electrode structure in the cycle process is improved. The electrochemical performance of the electrode of the lithium ion battery can be improved when the in-situ cross-linked polymer binding agent is used for preparing the electrode in situ, and particularly a more obvious improving effect is achieved on high specific capacity positive pole lithium-rich materials, a negative pole silicon substrate, tin-based materials and Li-S-based materials.

Description

technical field

[0001] The invention relates to an in-situ cross-linked polymer binder for lithium ion batteries and an electrode of lithium ion batteries prepared by using the polymer binder. Background technique

[0002] Lithium-ion batteries have the advantages of high specific energy, high working voltage, and long cycle life, and have been developed rapidly since their commercialization. With the application of lithium-ion batteries in the field of hybrid electric vehicles and electric vehicles, the demand for lithium-ion batteries with high energy density is increasing. However, electrode materials with higher specific capacity are often accompanied by larger volume changes during the intercalation / delithiation process. In the long-term cycle process, this volume change will lead to the deterioration of the electrode structure, resulting in accelerated capacity decay of the electrode and shortening the cycle life of lithium-ion batteries with high specific capacity. ...

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