Hydrothermal Synthesis of Li2MnSiO4 Powders as a Cathode Material for Lithium Ion Cells

Li2MnSiO4 cathode materials were prepared by hydrothermal reaction at 150 degrees C using LiOH, Si(OC2H5)(4) and Mn(Ac)(2)center dot 4H(2)O as raw materials followed by a low temperature heat annealing at 650 degrees C. The samples were characterized by XRD, SEM and FTIR. The powders electrochemical performance was investigated in terms of cycling behavior. Nanometer-sized flake crystalline particles of Li2MnSiO4 are obtained with some degree of agglomeration and little impure phases are detected after annealing. The charge capacity of the Li2MnSiO4 samples is 306 mAh/g (about 1.84 Li+ per unit formula extracted), and the discharge capacity is 114 mAh/g (about 0.68 Li+ per unit formula inserted) in the first cycle in the voltage range of 1.5 similar to 4.8 V under a rate of C/20. With increasing cycle number, the cell exhibits a well cycle performance with more than 95% coulombic efficiency and the maintenance of 61% of its discharge capacity after 50 cycles.