Facile synthesis of hollow carbonized polyaniline spheres to encapsulate selenium for advanced rechargeable lithium–selenium batteries

A hollow carbonized polyaniline spheres/selenium (HCPS/Se) composite was prepared by a simple combination method of a self-assembly method, pyrolysis and vapor phase infusion process as a cathode material for Li–Se rechargeable batteries. The composites were characterized and examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, the X-ray photoelectron spectroscopy and electrochemical methods, such as cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge tests. The HCPS/Se composite cathode can deliver relative high capacity, high Coulombic efficiency and good cycling performance. The electrochemical results show that the HCPS/Se composite cathode exhibits an initial discharge specific capacity of 571.5   mA   h   g −1 and retains 298.7   mA   h   g −1 with high Coulombic efficiency after 100 cycles at a high rate of 0.5   C (337.5   mA   h   g −1 ), which are higher than that of the pristine selenium cathode. The excellent electrochemical properties benefit from the high conductivity and the hollow structures of the carbonized polyaniline spheres.