Synthesis and Electrochemical Performance of Li2Mn1-xMgxSiO4 Cathode Materials for Li-ion Battery

A kind of doped-type cathode materials of Li2Mn1-xMgxSiO4 for Li-ion batteries has been prepared by solid-state calcination method in nitrogen. The samples were characterized by TG-DTA, XRD, SEM and electrochemical performance measurement. The TG-DTA curves and XRD patterns of precursor show that the Li2MnSiO4 can be obtained at 750 degrees C. The XRD patterns indicate that the Li2MnSiO4 crystallized in an orthorhombic structure with a space group of Pmn2(1). The XRD patterns of doped samples indicate that the crystallinity of Li2MnSiO4 is improved. Doped-Mg markedly affects the microscopic morphology of samples. The uniform particle size and little agglomerated sub-micron powder can be obtained by proper doping quantity. The electrochemical test demonstrates that the Li2Mn0.98Mg0.02SiO4 shows the best electrochemical performance with an initial discharge capacity of 124.6 mAh.g(-1), 38% of the theoretical capacity, and retains a discharge capacity of 60 mAh.g(-1) after 20 cycles.