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

Abstract

The invention discloses a lithium battery negative pole piece with excellent cycle performance and a manufacturing method thereof, and a lithium ion battery. The negative pole piece comprises a current collector, a conductive adhesive layer, a negative pole material layer and a composite conductive layer which are successively arranged on the current collector. A surface of the current collector is coated with the adhesive layer so that an adhesive force between the negative pole material and the current collector can be effectively improved. The adhesive layer is a conductive polymer binder,overall electronic conductivity of the pole piece can be improved, and meanwhile, a rate capability of the pole piece is increased. The negative pole material layer coated on the adhesive layer can effectively buffer a stress problem caused by volume expansion of a silicon material, the adhesive force between a diaphragm and the current collector is increased, and the negative pole material is prevented from falling off. The composite conductive layer which is finally coated can effectively improve a problem of conductive contact between the materials caused by a volume effect of a silicon negative pole material. Simultaneously, a lithium salt additive is added into the composite conductive layer so that a problem of irreversible capacity losses of the battery can be improved.

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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