摘要
以苯为碳源,在900℃下采用TVD(thermal vapor deposition)法对螺旋结构碳纳米管(Helical carbon nano-tubes,HCNTs)进行了包碳修饰,采用XRD、SEM、TEM、BET等检测方法对所制备材料进行了表征分析.包碳后HCNTs的比表面积明显降低.研究了包碳HCNTs用作锂离子电池负极材料的性能,结果显示适量包碳不仅提高了HCNTs的首次库仑效率,而且改善了其循环稳定性和倍率充放电性能.当TVD包碳45 min、HCNTs增重约220 wt%时,首次库仑效率从59.2%提高到77.8%,在1.0C、2.0C、5.0C以及10.0C倍率下的放电比容量分别为265.6、245.7、196.0、163.2 mAh/g,在10.0C下循环95次后放电比容量保持率为93.3%.过多的碳包覆虽然会进一步提高材料的首次库仑效率和循环稳定性,但会导致其倍率性能变差.
The helical carbon nanotubes（HCNTs） was modified with carbon through thermal vapor deposition（TVD） of benzene at 900 ℃,and characterized by X-ray powder diffraction,transmission electronic microscope,scanning electronic microscope and Brunau-Emmertt-Teller method.The specific surface area of the HCNTs de-creased after carbon coating.The obtained carbon coated HCNTs used as anode materials of Li-ion battery were studied.The results revealed that appropriate amount of carbon coating could improve the first columbic efficiency,the cycling stability and rate charge/discharge performance of the HCNTs.After 45 min carbon coating,HCNTs gained a weight increase approximately 220wt%,with its first columbic efficiency increasing from 59.2% to 77.8%,and delivered a discharge capacity of 265.6,245.7,196.0,163.2 mAh/g at the rates of 1.0C,2.0C,5.0C and 10.0C,respectively.After 95 cycles at 10.0C,its discharge capacity retention was 93.3%.Although excessive carbon coat-ing could further improve the first coulumbic efficiency and cycling stability of HCNTs,it also degraded the rate capability.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第6期631-637,共7页
Journal of Inorganic Materials
基金
国家"863"计划项目(2009AA03Z337)~~
