摘要
采用流变相法合成LiNi0.5Mn1.5O4粉末。以甲醛为还原剂,采用化学镀法制备LiNi0.5Mn1.5O4/Ag复合材料。通过X射线衍射分析、扫描电镜分析以及电化学测试等手段对LiNi0.5Mn1.5O4/Ag的微观结构、表面形貌和电化学性能进行研究。结果表明:在LiNi0.5Mn1.5O4/Ag中,LiNi0.5Mn1.5O4表面被包覆一层分散均匀且颗粒大小均匀的Ag,Ag颗粒的大小为200～300nm。Ag颗粒的存在增加LiNi0.5Mn1.5O4颗粒之间的电子导电性,降低电池的极化作用,减少锰的溶解,使得LiNi0.5Mn1.5O4/Ag具有比LiNi0.5Mn1.5O4更高的可逆容量、更稳定的循环性能和更好的倍率性能。以0.2C放电时,LiNi0.5Mn1.5O4/Ag的首次放电容量达到143.8mA·h/g;而经100次循环后,以0.2C和2.0C放电时,LiNi0.5Mn1.5O4/Ag的容量保持率分别达到99.2%和86.8%。
LiNi0.5Mn1.5O4 powders were prepared by rheological method.LiNi0.5Mn1.5O4/Ag composite was prepared by electroless plating method using formaldehyde as reductant.The microstructure,surface morphology and electrochemical properties of LiNi0.5Mn1.5O4/Ag composite were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and electrochemical methods.The phase analysis shows that Ag particles with a uniform size of 200-300 nm are dispersed on the surface of LiNi0.5Mn1.5O4 instead of entering the spinel structure.According to the electrochemical tests results,it is clear to see that Ag additives efficiently improve the cycling stability,reversibility and high-rate discharge capacity of pristine LiNi0.5Mn1.5O4 by increasing the electrical conductivity between LiNi0.5Mn1.5O4 particles,decreasing the polarization of cathode and reducing the dissolution of Mn.The first discharge capacity of LiNi0.5Mn1.5O4/Ag composite is higher than 143.8 mA·h/g at 0.2C.After cycling 100 times at 0.2C and 2.0C,the capacity retention of LiNi0.5Mn1.5O4/Ag composite are 99.2% and 86.8%,respectively.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2010年第4期801-806,共6页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(20376086)
中国博士后科学基金资助项目(2005037700)
湖南省自然科学基金资助项目(07JJ3014)
湖南省教育厅科学研究资助项目(07A058)
中南大学博士后科学基金资助项目(2004107)
