摘要
采用溶胶-凝胶法制备Li4/3Ti5/3O4/Ag复合材料,通过X射线衍射、扫描电子显微镜、恒电流充放电及交流阻抗等技术检测和分析合成产物的物相、形貌及电化学性质。研究表明,在Li4/3Ti5/3O4中添加Ag后Li4/3Ti5/3O4的Ti—O键没受影响,Li4/3Ti5/3O4/Ag及Li4/3Ti5/3O4的晶格常数非常接近,Ag没有进入Li4/3Ti5/3O4晶格,只是均匀地分散在Li4/3Ti5/3O4颗粒中。与Li4/3Ti5/3O4相比,Li4/3Ti5/3O4/Ag复合材料具有更高的比容量,更高的库仑效率以及更低的极化。添加Ag后对Li4/3Ti5/3O4锂离子扩散系数影响不大。电化学循环过程中,Li4/3Ti5/3O4/Ag的容量损失小于Li4/3Ti5/3O4,且随着充放电倍率的增加两者容量损失差距变大。Ag的添加大大地改善了Li4/3Ti5/3O4的循环性能,尤其是大电流循环性能。
The powders of Li4/3Ti5/3O4/Ag composite were prepared by the sol-gel technique.Phase identification,surface morphology and electrochemical properties were investigated with X-ray diffraction,scanning electron microscopy,galvanostatic charge-discharge experiments,and electrochemical impedance spectroscopy.Results show that the Ti-O bond is not affected by the adddition of Ag.Li4/3Ti5/3O4/Ag and Li4/3Ti5/3O4 have very similar crystal lattice parameters.Ag does not enter the Li4/3Ti5/3O4crystal and disperses homogeneously in Li4/3Ti5/3O4 particles.Compared with Li4/3Ti5/3O4,Li4/3Ti5/3O4/Ag composite has higher specific capacity,higher columbic efficiency and lower polarization.The addition of Ag has little effect on the lithium ion diffusion of Li4/3Ti5/3O4.The capacity loss of Li4/3Ti5/3O4/Ag is smaller than that of Li4/3Ti5/3O4 during the cycling.The addition of Ag greatly improves the cycleability of Li4/3Ti5/3O4 powders,especially at the higher charge-discharge rate.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2010年第8期751-754,759,共5页
Fine Chemicals
基金
湖南省教育厅自然科学基金资助项目(07B060)
湖南省科技厅资助项目(2009FJ3045)~~
关键词
煅烧
锂离子
阻抗
电化学
功能材料
calcination
lithium ion
impedance
electrochemistry
functional materials
