SILICON-BASED COMPOSITE MATERIAL WITH HOLLOW/POROUS STRUCTURE, AND PREPARATION METHOD THEREFOR

摘要

Disclosed is a silicon-based composite material with a hollow/porous structure, comprising a hollow/porous structure, a silicon-carbon composite layer and a coating layer, wherein the silicon-carbon composite layer is formed by uniformly dispersing nanosilicon or silica in an conductive carbon network, the conductive carbon network in the silicon-carbon composite layer is formed by high-temperature pyrolysis of a binder, and the coating layer is a carbon coating layer, there being at least one layer. The composite material of the present invention is prepared by a method involving using nanosilicon/silica, a binder and a salt, mixing same until uniform, and then subjecting same to spray pelletization, high-temperature sintering, washing with water and desalination, and a coating treatment. The present invention relates to a silicon-carbon negative electrode material for a lithium ion battery having advantages such as a high initial efficiency, a low expansion, and a long cycle, which slows down the growth of crystal grains of the silicon material during heat treatment, effectively avoids pulverization of the material in the cycle process, alleviates the volume expansion effect of the silicon-based material and improves the cycle performance, and can improve the conductivity and rate capability of the material.