Cyclic voltammetry studies on 4 V and 5 V plateaus of non-stoichiometric spinel Li_(1+x)Mn_(2-y)O_4  

作　　者：白莹 吴川 吴锋 王国庆 

机构地区：[1]School of Chemical Engineering and Environment, Beijing Institute of Technology Beijing 100081, China National Development Center for High Techn ology Green Materials, Beijing 100081, China

出　　处：《中国有色金属学会会刊：英文版》2006年第2期402-408,共7页Transactions of Nonferrous Metals Society of China

基　　金：Project(2002CB211800) supported by the National Basic Research Program of China

摘　　要：Li1+xMn2?yO4 spinels with various Li/Mn ratios were synthesized by a solid-state reaction. By X-ray diffraction analysis, Li2MnO3 was detected as a second phase with increasing the Li/Mn ratio; and the role of Li2MnO3 in Li1+xMn2-yO4 spinel was discussed. A slow scanning cyclic voltammetry(CV) at the rate of 0.1 mV/s was adopted to characterize the evolutions of 4 V and 5 V plateaus of Li1+xMn2-yO4 spinels. An additional Li+ insertion in 4 V region was observed in both Li-lack and Li-rich spinels at 3.95 V, which is different from the general Li+ insertion with weak Li-Li interaction and strong Li-Li interaction; and this plateau disappeared in the subsequent cycles. The 4.4 V/3.8 V plateaus correspondent to Li+ insertion and extraction of Li2MnO3 were discussed, and these plateaus have a high reversibility with cycling. The 5 V plateau was found only in the Li-rich samples, and this plateau has a tendency to emerge at higher voltage region with increasing Li/Mn ratio.Li1＋xMn2-yO4 spinels with various Li/Mn ratios were synthesized by a solid-state reaction. By X-ray diffraction analysis, Li2MnO3 was detected as a second phase with increasing the Li/Mn ratio; and the role of Li2MnO3 in Li1＋xMn2-yO4 spinel was discussed. A slow scanning cyclic voltammetry（CV） at the rate of 0.1 mV/s was adopted to characterize the evolutions of 4 V and 5 V plateaus of Li1＋xMn2-yO4 spinels. An additional Li＋ insertion in 4 V region was observed in both Li-lack and Li-rich spinels at 3.95 V, which is different from the general Li^＋ insertion with weak Li-Li interaction and strong Li-Li interaction; and this plateau disappeared in the subsequent cycles. The 4.4 V/3.8 V plateaus correspondent to Li^＋ insertion and extraction of Li2MnO3 were discussed, and these plateaus have a high reversibility with cycling. The 5 V plateau was found only in the Li-rich samples, and this plateau has a tendency to emerge at higher voltage region with increasing Li/Mn ratio.

关 键 词：LIMN2O4 LI2MNO3 锂离子电池 循环伏安法 化学计量 

分 类 号：TB321[一般工业技术—材料科学与工程]