Preparation and electrochemical characterisation of polypyrrole-coated Li2SnO3 anode materials for lithium-ion batteries

Polypyrrole-coated Li2SnO3 (Li2SnO3/PPy) nanocomposite has been prepared by a micro emulsion polymerisation. The X-ray diffraction and transmission electron microscopy analysis reveals that the Li2SnO3 crystal particles with a uniform and block structure are coated by PPy with amorphous behaviour. The particle sizes of Li2SnO3 are in the range from 40 to 50 nm with clear lattice fringes. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis reveals the surface structure and the binding nature of the elements of Li2SnO3/PPy composite. Electrochemical measurement suggests that Li2SnO3/PPy nanocomposite exhibits better cycling properties and lower initial irreversible capacities than Li2SnO3 as anode materials for lithium-ion batteries. At a current density of 60 mA/g in the voltage about 0.01-2.0 V, the first discharge-charge capacities of Li2SnO3/PPy are 1482.2 and 892.1 mAh/g, whereas they are 2104.5 and 1417.0 mAh/g for Li2SnO3. The retention capacity of Li2SnO3/PPy (560.1 mAh/g) is higher than that of Li2SnO3 (510.2 mAh/g) after 50 cycles.