核壳结构硅/多孔炭粉体的制备

Preparation of core-shell silicon/porous carbon powders

以硅粉和酚醛树脂(PR)为原料,采用包混工艺制备硅/多孔炭核壳结构粉体。研究了酚醛树脂和硅粉含量以及老化温度对硅/酚醛树脂前驱体粉体形成能力的影响,并采用X射线衍射、扫描电镜和能谱等手段对粉体进行表征。研究表明,当PR与乙醇的体积比小于1,Si粉与乙醇的质量比小于2,老化温度在30℃～60℃时可以制备出性能良好的前驱体粉体;硅/多孔炭核壳粉体的炭含量随着前驱体粉体酚醛树脂含量的增加而增加;硅/多孔炭核壳粉体的炭壳由酚醛树脂高温裂解形成的树脂炭构成,炭壳的孔则由树脂裂解过程中释放出的大量气体形成。

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.