Effects of transition metal doping and surface treatment to improve the electrochemical performance of Li2MnO3

A novel strategy to improve the electrochemical performance of Li2MnO3 using transition metal doping by the mechanochemical process is proposed. Li2MnO3 precursors are treated with transition metal containing chemicals in the mechanochemical process, followed by heat treatment. Cr containing Li2MnO3, with only 1 mol% Cr doping, exhibits unique electrochemical properties with a large initial discharge capacity of 234.9 mAh g(-1), which is superior to the 205.0 mAh g(-1) of pristine Li2MnO3, and all other transition-metal containing oxides. The structures of Li2MnO3 and Li2MnO3 with the transition metal element doping (TM-Li2MnO3) are studied by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and the electrochemical characteristics are further investigated using electrochemical impedance spectroscopy (EIS) measurements.