TiO2–Se composites as cathode material for rechargeable lithium–selenium batteries

Titania-selenium (TiO2–Se) composite cathode materials were successfully synthesized by a simple melt-diffusion method for lithium–selenium batteries. The composites were characterized and examined by X-ray diffraction, nitrogen adsorption/desorption measurements, scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge tests. It is found that selenium particles and TiO2 are well-distributed in the composites. The TiO2–Se composite cathode can deliver relative high capacity and good cycling performance. The electrochemical results showed that the TiO2–Se composite cathode exhibits an initial discharge specific capacity of 481 mAh/g and 158 mAh/g over 50 cycles at 0.1 C, which are higher than that of pristine selenium. The improvements of electrochemical performances were due to the good dispersion of selenium in the pores of TiO2 particles and the excellent adsorbing effect on polyselenides of TiO2.