摘要
以商业化V2O5粉体和H2O2为原料,采用溶胶-凝胶法制备了V2O5凝胶,将V2O5凝胶稀释后进行冷冻干燥得到V2O5前驱体,最后在空气中450℃煅烧2 h得到正交晶系的V2O5样品。经过X射线衍射(XRD)、热重分析(TGA)和场发射电子扫描电镜(FESEM)分析发现,V2O5前驱体是具有2D片状结构的V2O5·n H2O粉体,煅烧后转变为2D片状结构的正交晶系V2O5粉体。采用循环伏安(CV)、电化学交流阻抗(EIS)和充放电测试研究了V2O5样品的Li+扩散系数、电化学反应阻抗、倍率性能和电化学循环稳定性,发现V2O5样品的Li+扩散系数和电化学反应阻抗大小与其放电深度密切相关,所制备的2D片状V2O5样品具有较好的倍率性能和优异的电化学循环稳定性。
V2O5 gel was prepared by sol-gel method with commercial V2O5 powders and H2O2 as raw materials. Then the V2O5 gel was diluted and freeze-dried to obtain V2O5 precursor. The V2O5 precursor was further treated at 450 °C in air for 2 h to obtain orthorhombic V2O5 sample. X-ray diffraction （XRD）, thermogravimetric analysis （TGA）, and field emission scanning electron microscope （FESEM） analysis reveal that the precursor is V2O5·nH2O powders with 2D sheet structure, and after calcining in air the V2O5·nH2O powders change into 2D orthorhombic V2O5 powders. Cyclic voltammograms （CV）, electrochemical impedance spectroscopy （EIS）, and charge-discharge tests were performed to study lithium ion diffusion coefficient, electrochemical reaction impedance, rate performance, and electrochemical cycling stability of the V2O5 sample. The results show that the lithium ion diffusion coefficient and electrochemical reaction impedance are closely related to depth of discharge of the V2O5 sample. The prepared 2D V2O5 sample has good rate performance and excellent electrochemical cycling stability.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2015年第1期158-164,共7页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金项目(21263003
51464009
51204061)
广西自然科学基金项目(2012GXNSFAA053026
2014GXNSFBA118238)
广西矿冶与环境科学实验中心科研项目(KH2011ZD005)
关键词
五氧化二钒
溶胶-凝胶法
冷冻干燥
储锂性能
vanadium pentoxide
sol-gel method
freeze-drying
lithium storage performance
