Self-templated preparation of hollow mesoporous TiN microspheres as sulfur host materials for advanced lithium–sulfur batteries

Although lithium–sulfur (Li–S) batteries are an advanced energy storage system, their development has been impeded due to poor cycling stability and low sulfur utilization. Hollow TiN microspheres with a porous shell were prepared to host sulfur (TiN-S) for use as a Li–S battery cathode. The TiN-S electrode delivered a high capacity of 1206.1 mA h/g at 0.1 C, and a narrow value domain of 1218.2 ± 17.7 mA h/g was obtained from initial discharge capacities of 9 cells. Furthermore, a capacity of 623.3 mA h/g (with a retention of 67.5%) was maintained after 300 progressive cycles at 1 C. The superior cycling performance of the TiN-based cathode can be ascribed to the following: (1) TiN improved the electrical conductivity of the cathode, effectively increasing the active sulfur utilization; (2) the hollow TiN microspheres with pores restricted the soluble polysulfides by both chemical and physical interactions; (3) the large void of the spherical cavity in TiN could accommodate the change in volume of the cathode during the discharge–charge processes.