Effects of sodium substitution on properties of LiMn_2O_4 cathode for lithium ion batteries  

作　　者：郭华军 李向群 何方勇 李新海 王志兴 彭文杰 

机构地区：[1]School of Metallurgical Science and Engineering,Central South University [2]School of Chemistry and Chemical Engineering,Central South University

出　　处：《Transactions of Nonferrous Metals Society of China》2010年第6期1043-1048,共6页中国有色金属学报（英文版）

基　　金：Project(2007CB613607) supported by the National Basic Research Program of China;Projects(2009FJ1002, 2009CK3062) supported by the Science and Technology Program of Hunan Province, China

摘　　要：Na-doped Li1.05Mn2O4 cathodes were synthesized using a sol-gel process.The samples were characterized by X-ray diffractometry(XRD),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and charge-discharge measurements. The results show that all the samples exhibit the same cubic spinel phase structure without impurity.The lattice constant and unit cell volume decrease with increasing the sodium dopant amount.As the molar ratio of sodium to manganese(x=n(Na)/n(Mn))increases from 0 to 0.03,the initial discharge capacity of the Li1.05Mn2O4 cathodes decreases from 119.2 to 107.9 mA·h/g,and the discharge capability at large current rate and the storage performance decline dramatically,while cycling performance at room temperature and 55℃are improved.The CV and EIS studies indicate that reversibility of Li1.05Mn2O4 cathodes decreases and the electrochemical impedance increases with increasing the sodium dopant amount.Na-doped Li1.05Mn2O4 cathodes were synthesized using a sol-gel process.The samples were characterized by X-ray diffractometry（XRD）,cyclic voltammetry（CV）,electrochemical impedance spectroscopy（EIS）and charge-discharge measurements. The results show that all the samples exhibit the same cubic spinel phase structure without impurity.The lattice constant and unit cell volume decrease with increasing the sodium dopant amount.As the molar ratio of sodium to manganese（x=n（Na）/n（Mn））increases from 0 to 0.03,the initial discharge capacity of the Li1.05Mn2O4 cathodes decreases from 119.2 to 107.9 mA·h/g,and the discharge capability at large current rate and the storage performance decline dramatically,while cycling performance at room temperature and 55℃are improved.The CV and EIS studies indicate that reversibility of Li1.05Mn2O4 cathodes decreases and the electrochemical impedance increases with increasing the sodium dopant amount.

关 键 词：lithium ion battery CATHODE LIMN2O4 SODIUM SUBSTITUTION 

分 类 号：TM912[电气工程—电力电子与电力传动] TP301.6[自动化与计算机技术—计算机系统结构]