In-situ synthesis of sulfur-TiO2 hollow shell materials for high-performance lithium-sulfur batteries

Abstract

Lithium-sulfur batteries with higher energy density are highly attractive, but the practical applications have been greatly affected by their poor cycle performance. Despite much effort has been devoted to design the structure of sulfur cathode to suppress polysulfide dissolution, relatively little emphasis has been placed on in-situ immobilizing the sulfur atoms. Herein, we demonstrate a new approach of in-situ immobilizing the sulfur atoms into the TiO2 host, in which, the polysulphides can localized in the cathode side and efficiently reused during cycling due to the novel S-TiO2 hollow shell structure. The battery based on the well-designed S-TiO2 cathode can deliver a discharge capacity of 601 mA h g-1 at 0.5 C after 100 cycles. The good electrochemical performance could be attributed to the homogeneous dispersing of sulfur in the TiO2 host in the in-situ formation process, and the hollow structure of the S-TiO2 materials. The economical and simple strategy to overcome the polysulfide dissolution issues provides a commercially feasible way for the construction of lithium-sulfur batteries.