Nitrogen-doped graphene-silicon composite negative pole material, preparation method thereof, and lithium ion battery

Abstract

The invention relates to a nitrogen-doped graphene-silicon composite negative pole material, a preparation method thereof, and a lithium ion battery, and belongs to the field of lithium ion battery material preparation. The nitrogen-doped graphene-silicon composite negative pole material is of a core-shell structure, the core of the core-shell structure is the nitrogen-doped graphene-silicon composite material, the shell of the core-shell structure is of a double-layer structure, and the double-layer structure consists of a silane coupling agent layer and an organolithium compound layer in sequence from inside to outside; and the silane coupling agent layer is silane coupling agent. By use of the nitrogen-doped graphene-silicon composite negative pole material, the expansion rate of a nanometer silicon material can be lowered, a lithium ion transmission rate and the gram volume of the negative pole material can be improved, and the silane coupling agent layer covers the outer surface of the core to improve the tap density and the structure stability of the material so as to improve the cycle performance of the lithium ion battery of the nitrogen-doped graphene-silicon composite negative pole material; the initial efficiency of the material of the lithium ion battery can be improved by an original lithium compound layer out of the silane coupling agent layer, sufficient lithium ions are provided for a large multiplying power charging and discharging process of lithium ions, and multiplying power performance is improved.

Description

technical field [0001] The invention relates to a nitrogen-doped graphene-silicon composite negative electrode material, a preparation method thereof, and a lithium ion battery, belonging to the field of lithium ion battery material preparation. Background technique [0002] At present, the negative electrodes of commercial lithium-ion batteries mainly use carbonaceous materials such as natural graphite and artificial graphite. The requirements for high-energy cathode materials such as spar high-voltage materials greatly limit the further improvement of the overall capacity of the battery. In order to meet the needs of high-capacity lithium-ion batteries, research and development of high-capacity anode materials has become very urgent and necessary. [0003] Among non-carbon anode materials, silicon-based materials have a high theoretical specific capacity of 4200mAh / g, abundant reserves, and low cost, making them the most promising anode materials for lithium-ion batteries...

AI Technical Summary

Problems solved by technology

The negative electrode material of this invention effectively improves the transmission rate and electronic conductivity of lithium ions, realizes rapid charge and discharge, and finally improves the rate performance, safety performance and cycle performance of the battery, but the coating effect on graphite is poor, which is not conducive to further improvement Cycle Performance of Li-ion Batteries

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