从SiCl_4合成多孔硅/碳复合材料及储锂性能研究

Synthesis and Lithium Storage Performance of Porous Silicon/Carbon Composite Material from SiCl_4

以Li13Si4和SiCl4为原料,通过简单的机械球磨法合成多孔硅/碳复合材料,通过控制Li13Si4颗粒的尺寸可以有效调节产物的比表面积。分别研究了包覆碳含量、多孔硅/Super P(导电碳)比表面积以及极片活性物质负载量对多孔硅/碳复合材料电化学性能的影响。结果表明:多孔硅/Super P比表面积为100.9 m2·g-1,化学气相沉积(CVD)包覆碳含量为25.3wt%(约6 nm厚)的复合材料具有最高的电化学活性,在300 mA·g-1的电流密度下,循环可逆比容量达到1 900 mAh·g-1,50次循环后容量仅衰减7.6%。

Porous silicon/carbon composite was prepared via a mechanochemical reaction between Lil3Si4 and SiCl4 under ball milling. Specific surface area of silicon/carbon composite can be adjusted by controlling the particle size distribution of Li13Si4. Effects of the carbon weight, specific surface area and active mass loading on the electrochemical performance were investigated. The results indicated that the composite material which combined specific surface area of 100.9 m2·g^1~ and chemical vapor deposition method （CVD） carbon coating with 25.3wt% （ca.6 nm in thickness）, exhibited a considerably high reversible capacity of 1 900 mAh ·g^-1 and an excellent cycling stability with only 7.6% capacity decay after 50 cycles at a current density of 300 mA· g^-1.