Synthesis and Performance of LiNi_(0.45)Mn_(0.55)O_2 as Cathodes for Li-ion Batteries with the Composite Properties of Materials

摘要

A compound as the lithium ion battery cathode materials were synthesized by high temperature solid phase synthesis method. The material is mainly the hexagonal structure and R3{top}m space group, and there is a little other phase. The XPS spectra display in the materials the Mn element existed by Mn~(4+) and the Ni element existed by the mix valent state between Ni~(2+) and Ni~(3+); the energy loss spectrum and ICP results are consistent, to ensure that the compounds is LiNi_(0.45)Mn_(0.55)O_2 which we need; SEM figure shows it has a loose structure, particle size is about 0.2μm. At a current density 30mA/g at room temperature AC impedance analysis results show that an initial discharge capacity of 298 mAh/g, which is higher than theoretical capacity of LiMnO_2 285 mAh/g, that may be because of the synthesis LiNi_(0.45)Mn_(0.55) O_2 is composite materials. After 13 circles it dropped to 93.2mAh/g and was steady, the efficiency reached 91.3%.