Li2Mn1-xMgxSiO4/C锂离子电池正极材料的合成和电化学性能研究

Li2Mn1-xMgxSiO4/C cathode material for lithium-ion batteries has been synthesized by a sol-gel method using LiCH3COOo2H2O, Mn(CH3COO)2o4H2O, Mg(CH3COO)2o4H2O, and Si(OC2H5)4 as starting materials under Ar/H2 atmosphere. Crystal structures and morphology of the as-prepared compounds were characterized by X-ray Powder Diffraction (XRD) and scanning electron microscopy (SEM). The Li2MnSiO4 material maintains orthorhombic structure with up to 10 wt % Mg doping on the Mn sites. Electrochemical tests of the cathode materials reveal that Mg doping can improve the specific capacity of Li2MnSiO4. An initial specific discharge capacity of 229 mAh g-1 can be achieved for the Li2Mn1-xMgxSiO4/C (x=0.1) cathode material at a current density of 16.65 mA g-1. The deterioration mechanism is also discussed based on the XRD and X-Ray Photoelectronic Spectroscopy (XPS) experiments.