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.