Fabricated and improved electrochemical properties of Li2MnSiO4 cathodes by hydrothermal reaction for Li-ion batteries

Li2MnSiO4 cathode materials were hydrothermally synthesized from commercial LiOH, Mn(Ac)2, Si(OC2H5)4 in aqueous solution. The technic factors, such as temperature, time, compactness and molar ratio of Li:Mn:Si, were systematically studied by orthogonal test method. The optimization hydrothermal synthesis of Li2MnSiO4 is determined as the condition of the reaction temperature at 200 °C, the reaction time of 72 h, the compactness of 75 vol% and the molar ratio of Li:Mn:Si as 2:1:1. Among them, the influence of the temperature on the electrochemical performance of the sample is the greatest. An X-ray diffraction pattern confirms the formation of the orthorhombic structure with Pmn21 space group. The Li/Li2MnSiO4 cells delivered an initial discharge capacity of 226 mAh/g for as-synthesized following heat-treated Li2MnSiO4 under the optimized conditions. It is surprising to note that heat-treated Li2MnSiO4 exhibits more stable and superior cycling performance than reported values elsewhere, which is due to the unique morphology as well as well crystallization during high temperature sintering.