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 2 h.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.