Novel nano-silicon-carbon lithium ion battery negative electrode material and preparation method thereof

Abstract

The invention relates to a novel nano-silicon-carbon lithium ion battery negative electrode material and a preparation method thereof, and belongs to the technical field of a lithium ion battery and the technical field of nanometer. The novel nano-silicon-carbon lithium ion battery negative electrode material comprises a spherical nano-silicon-carbon composite material and carbon; the spherical nano-silicon-carbon composite material is wrapped by the carbon; the spherical nano-silicon-carbon composite material consists of nano-silicon particles and carbon according to the weight ratio of 4:6;and the carbon is formed through organic carbon pyrolysis and accounts for 6 percent of the total weight of the battery negative electrode material. The carbon material is small in volume change and high in electric conductivity in the charging and discharging process as well as has high cycling stability, the silicon and the carbon have close chemical properties, and the silicon and the carbon can be combined tightly. The obtained novel nano-silicon-carbon negative electrode material solves the aggregation phenomenon of silicon particles in the charging and discharging process of the lithiumion battery well. The nano-silicon particles are wrapped by the carbon material, so that the electric conductivity of the material is improved.

Description

technical field [0001] The invention relates to a lithium-ion battery negative electrode material and a preparation method thereof, in particular to a novel nanometer silicon-carbon lithium-ion battery negative electrode material and a preparation method thereof, belonging to the technical field of lithium-ion batteries and the field of nanotechnology. Background technique [0002] As an important link in the new energy industry, lithium-ion batteries have been widely used. The market has higher and higher requirements for the energy density of lithium-ion batteries, which is increasing at a rate of 7%-10% every year. At present, graphite material is the most commonly used lithium battery anode material, but the theoretical lithium storage capacity of graphite anode material is only 372Ma.h / g. In 2016, the state issued a hard target for the energy density of power batteries. According to the "Technical Roadmap for Energy Saving and New Energy Vehicles", in 2020, the energy ...

AI Technical Summary

Problems solved by technology

[0004] However, the cycle performance and capacity of silicon anode materials will be severely attenuated during the charging and discharging process of lithium-ion batteries.

Silicon expands up to 320% in volume during charging and discharging, and the huge volume change causes the active material to fall off from the current collector, resulting in a sharp decline in the cycle performance of the battery; at the same time, silicon particles are prone to agglomeration during charging and discharging. Due to the negative electrode material, there is also the problem of poor electrical conductivity, which affects performance.