Electrochemical and structural characteristics of metal oxide-coated lithium manganese oxide (spinel type): Part I. In the range of 2.5–4.2 V

The electrochemical and structural characteristics of the metal oxide-coated spinel were investigated in the range of 2.5–4.2 V. Metal oxide coating on commercial spinel powder (LiMn2−xMxO4, M=Zr, Nikki, Japan) was carried out using the sol–gel method. Al2O3/(PtOx or CuOx)-coated spinel exhibited improved cyclability compared to bare spinel. Impedance analysis results indicated that electrochemical resistance value was not consistent with cycle performance. The improved cycle performance of metal oxide-coated spinel may be due to formation of a new Li2Mn4O9, Li2MnO3 phase, which is expected to have stability to phase transition (Jahn–Teller distortion).