硅基复合材料的电化学特性

Electrochemical Characteristics of Silicon-based Composites

将氧化亚硅,铝和石墨经过2步球磨盐酸刻蚀处理,再包覆碳,可制得纳米孔-S i/G/C复合材料,其比容量高达600 mAh/g,电化学循环性能稳定,但首次放电效率较低.氧化亚硅和铝球磨后再经高温热处理,可以促使氧化亚硅完全还原.高温下A l2O3产物的晶型结构由γ相转为稳定难溶的α相,硅/A l2O3复合材料难以刻蚀制孔,而硅/A l2O3/G/C复合材料则显示较高的首次放电效率但循环稳定性较差.

The nano-porous Si/G/C composite was obtained by two-step ball milling with SiO, A1 and graphite, along with HCI acid etching followed by carbon incorparation. This composite demonstrated the reversible capacity of 600 mAh/g with excellent cycling stability, but low initial cycle efficiency is low. A high-temperature treat- ment after ball-milling of SiO and A1 could promote the Complete reduction of SiO. However, the crystalline structure of Al2O3 product changed from T-phase to a-phase, which it can no longer be etched by HCI. The Si/ Al2O3/G/C composite exhibited higher efficiency at the first cycle but relatively poorer cyclability.