A Facile Molten Salt Method for Diverse TiC/C Hybrid as Effective Polysulfide Confinement toward Stable Lithium–Sulfur Batteries

Abstract

Traditional carbon materials suffer from weak adsorption of lithium polysulfides and excessive consumption of electrolyte. A simple and feasible molten salt method is applied for constructing an active nanocrystalline TiC shell on the surface of porous carbon. The highly active TiC nanoshells endow the core–shell composite with efficient chemical–physical synergistic adsorption, which can effectively confine and convert polysulfides, thereby improving the electrochemical performance of lithium–sulfur batteries. The lithium–sulfur batteries assembled with modified separator deliver a high initial discharge specific capacity of 1396 mAh g−1 at a discharge rate of 0.5 C and a high capacity retention of 747.1 mAh g−1 after 500 cycles, with a high coulombic efficiency of 98% during cycling. Besides, this molten salt method can be applied to modify the porous carbon materials of various composite sulfur cathodes such as graphene, carbon nanotubes, and 3D nonwoven carbon fabrics.