Preparation of coreshell silicon/porous carbon powders

Core-shell silicon/porous carbon powders were fabricated by coating silicon powders with phenolic resin, followed by carbonization at 800℃ for 2h. The influence of phenolic resin volume percent, silicon mass percent and aging temperature on the formation of silicon/phenolic resin precursor powders was investigated. The resulting powders were characterized by X-Ray diffraction and scanning electron microscopy The optimum conditions for the formation of silicon/phenolic resin precursor powders are found to be: volume ratio of phenolic resin to alcohol, ＜1; mass ratio of Si to alcohol, ＜2; and aging temperature, at 30-60℃. The resin carbon shell of the resulting powders is formed by the pyrolysis of phenolic resin during carbonization treatment and the carbon content in the core-shell silicon/porous carbon increases with the content of phenolic resin in precursor powders. The large amount of gas produced in the pyrolysis process creates pores in the carbon shell.