纳米CoSb作为锂离子电池新型负极材料的研究

Study of nanosized CoSb as novel anode material of Li-ion batteries

用溶剂热法合成了纳米尺寸的CoSb合金粉末,并研究了该合金粉末作为锂离子二次电池新型负极材料的电化学性能.合成的合金粉末经过了X射线衍射(XRD)、透射电镜(TEM)和场发射扫描电镜(FESEM)的表征,研究发现,该合金粉末的首次可逆容量达到362 mA.h/g,经过了20个循环后,其可逆容量仍保持在320mA.h/g.与用悬浮熔炼/球磨工艺所得的微米尺寸的合金粉末相比,用溶剂热方法制得的纳米CoSb粉末的可逆容量和循环性能均显著提高.这是因为,纳米CoSb粉末颗粒尺寸较小,在充放电过程中绝对体积变化较小(尤其在最初的几个循环中),这显著地减缓了活性材料的粉化和剥落.

Nanosized CoSb powder was prepared by solvothermal route and studied as a novel candidate an ode material for secondary Li-ion batteries. The alloy powder was characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and field emission scanning electron microscopy （FESEM）. It was found that the first reversible capacity of the nanosized CoSb reaches 362 mA · h/g and a capacity of 320 mA · h/g is still maintained after 20 cycles. The nanosized CoSb powder shows both increased reversible capacity and improved cycling stability compared to its microsized counterpart prepared by levitation-melting/ball-milling route. This is due to the fact that nanosized CoSb undergoes smaller absolute volume changes （especially in the initial cycles） because of its smaller particle size, leading to significantly reduced pulverization and exfoliation of the active material.