Hollow/porous silicon-based composite material and preparation method thereof

Abstract

A hollow/porous silicon-based composite material includes a hollow/porous structure, a silicon-carbon composite layer and a carbon coating layer. The silicon-carbon composite layer is formed by uniformly dispersing nano silicon/silicon oxide in a conductive carbon mesh formed by high-temperature pyrolysis of a binder. The composite material is prepared by uniformly mixing nano silicon/silicon oxide, the binder and the salt, and then carrying out spray granulation, high-temperature sintering, water washing for desalination, and a coating treatment. The grain growth of the silicon material is slowed down during the heat treatment process, the pulverization of the material is effectively avoided, the volume expansion effect of the silicon-based material is alleviated, the cycle performance of the silicon-based material is improved, and the conductivity and rate performance of the material is enhanced. The silicon-based composite material is a silicon-carbon anode material for lithium ion batteries with high first-cycle efficiency, low expansion and long cycle.