Hollow-structure carbon and silicon negative pole material used for lithium ion battery, and preparation method of hollow-structure carbon and silicon negative pole material

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a hollow-structure carbon and silicon negative pole material used for a lithium ion battery. The inner side of the negative pole material is of a hollow structure, and a wall layer of the negative pole material comprises an inner wall and an outer wall; the inner wall is subjected to homogeneous phase compounding by nanometer silicon and a low carbon residue carbon source; the outer wall is a carbon coating layer formed by an original pyrolysis carbon source; the particle size of the nanometer silicon is 5-300nm; the softening point of the low carbon residue carbon source is less than 200DEG C, and a carbon residue rate is less than 40%; the thickness of the outer wall is 0.1-10 microns; thethickness of the inner wall is 1-8 microns. The invention designs the large hollow-structure carbon and silicon negative pole material used for the lithium ion battery, a large hollow part is reservedfor the volume expansion of silicon, the volume expansion problem of a silicon negative pole can be obviously solved, the formation of the large hollow structure is guaranteed by the low carbon residue carbon source, meanwhile, the nanometer silicon is subjected to homogeneous phase dispersion, a transmission channel and rate of electrons and lithium ions can be guaranteed, and the carbon coatinglayer coats the outmost layer so as to form a protection shell for isolating electrolyte.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and relates to a hollow-structure silicon-carbon negative electrode material for lithium-ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, small self-discharge, no memory effect, wide operating voltage range, long service life, and no environmental pollution. They are currently the main power source for new energy vehicles. The key electrode material of lithium-ion battery is the final decisive factor of battery performance, and the negative electrode material plays a vital role in improving the performance of lithium-ion battery. However, the specific capacity of the traditional graphite negative electrode is close to the theoretical value of 372mAh / g, and there is little room for improvement. Therefore, the development of new high-performance electrode materials has become a research hots...

AI Technical Summary

Problems solved by technology

However, the hollow structure reduces the contact points between the nano-silicon and the carbon layer, making it difficult to ensure the rapid transmission of lithium ions and electrons.

Images