Enhanced performance of Fe1.5P anode materials by SnO2/Sn modification for lithium-ion batteries

SnC2O4 was prepared facilely from SnCl2·2H2O and H2C2O4·2H2O by a mechanochemical reaction at room temperature, and SnO2/Sn-modified Fe1.5P was synthesized via in situ thermal decomposition of SnC2O4 on the surface of Fe1.5P in Ar. The crystal structure, the surface morphology and the chemical composition of the as-prepared samples were investigated by X-ray diffraction, field-emission scanning electron microscopy, X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy, respectively. The electrochemical performance was evaluated by galvanostatic charge/discharge tests and cyclic voltammetry. As for the as-synthesized SnO2/Sn composite, the 1st and 2nd discharge capacities at 0.1 C current rate are 1616.8 and 1080.5 mAh g−1, respectively, and the discharge capacity remained 531.2 mAh g−1 after 30 cycles at various current rates of 0.1, 0.2 and 0.5 C, which are better than that of the reported porous SnO2 nanospheres. SnO2/Sn-modification greatly enhances the electrochemical performance of Fe1.5P, and the discharge capacity of the SnO2/Sn-modified Fe1.5P retains 96.2 mAh g−1 after 250 cycles at different current rates, which is 46.8% higher than that of the original Fe1.5P, and 450% higher than that of the SnO2/Sn.