Lithium battery negative pole piece with excellent cycle performance and preparation method thereof, and lithium ion battery

Abstract

The invention discloses a lithium battery negative pole piece with excellent cycle performance, a preparation method thereof, and a lithium ion battery. Wherein, a negative electrode sheet includes a current collector, and further includes a conductive adhesive layer, a negative electrode material layer and a composite conductive layer sequentially arranged on the current collector. The present invention can effectively improve the adhesion between the negative electrode material and the current collector by coating an adhesion layer on the surface of the current collector; the adhesion layer is a conductive polymer binder, which can improve the overall electronic conductivity of the pole piece, At the same time, the rate performance of the pole piece is improved; the negative electrode material layer coated on the adhesive layer can effectively buffer the stress problem caused by the volume expansion of the silicon material, and at the same time improve the adhesion between the diaphragm and the current collector to prevent the negative electrode from The material falls off; the composite conductive layer coated at the end can effectively improve the conductive contact between materials caused by the volume effect of the silicon negative electrode material. At the same time, the lithium salt additive is added to the composite conductive layer, which can improve the irreversible capacity loss of the battery .

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a negative pole piece of a lithium-ion battery with excellent cycle performance, a preparation method thereof, and a lithium-ion battery with the negative pole piece. Background technique [0002] At present, graphite and modified graphite are widely used in commercial lithium-ion battery materials, but their theoretical capacity is only 372mAh / g, and the energy density is low, which is difficult to meet the needs of future development of power batteries. In recent years, the development of new lithium-ion electrode materials has attracted widespread attention from experts at home and abroad, especially the development of negative electrode materials with high energy density and good cycle life has become one of the hot spots in the research of lithium-ion battery electrodes. Due to its high theoretical capacity (4200mAh / g), low lithium extraction / intercalation pote...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the problem of material pulverization and easy falling off from the current collector due to volume expansion of the existing silicon material negative electrode sheet during charge and discharge; the volume expansion effect leads to poor conductive contact performance between materials and SEI film on the surface of silicon particles Continuous growth, which causes the problem of irreversible capacity loss of silicon negative electrode materials, proposes a negative electrode sheet of a lithium-ion battery with excellent cycle performance and its preparation method and a lithium-ion battery with the negative electrode sheet

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