Synthesis and materials characterization of Li2MnO3–LiCrO2 system nanocomposite electrode materials

A series of Li[Cr {sub x}Li{sub (1-x)/3}Mn{sub 2(1-x)/3}]O{sub 2} (0.2 {<=} x {<=} 0.4) with nanocomposite structures was synthesized by a solution method with subsequent quenching. The sample structures were investigated by X-ray diffraction (Rietveld refinement), electron diffraction and HRTEM. According to co-indexed electron diffraction patterns and HRTEM images, Li[Cr{sub 0.211}Li{sub 0.268}Mn{sub 0.520}]O{sub 2} was found to be composed of solid solution powders and Li[Cr{sub 0.290}Li{sub 0.240}Mn{sub 0.470}]O{sub 2} and Li[Cr{sub 0.338}Li{sub 0.225}Mn{sub 0.436}]O{sub 2} of nanocomposite powders indexed in monoclinic and hexagonal structure. Among the three compounds, the nanocomposite Li[Cr{sub 0.290}Li{sub 0.240}Mn{sub 0.470}]O{sub 2} cathode prevented spinel-like structural transformation during cycling and delivered a good reversible capacity of about 195 mAh/g.