Abstract:

 With the increasing demand for efficient and economic energy storage, lithium-sulfur (Li-S) batteries have become attractive candidates for the next-generation high-energy rechargeable batteries because of their high theoretical energy density and cost effectiveness. However, practical applications of the Li-S battery are hindered by poor cycle life, low coulombic efficiency, self-discharge, et al. Main reason of these issues is the polysulfide shuttle, which caused by the dissolution of polysulfides into the electrolyte and deposition on the lithium anode. Several strategies have been proposed in order to tackle these issues and improve the overall electrochemical performance of the Li-S batteries. In particular, among them, the preparation of sulfur hybrid materials by different carbon materials or various functional carbon based materials is frequently used. In this review, we present fundamental studies and technological development of various cathode materials for Li-S batteries, including their preparation, structure, morphology and battery performance. Based on the adsorption characteristics between the host and polysulfide, the materials are divided into two types: physical adsorption and chemical adsorption. Adjusting or functionalizing the electrode materials can effectively promote the performance of the Li-S batteries, and the mechanism is further revealed to gain a better understanding of the characteristics between the host and polysulfide. Finally, we give insights on the relation between the structure of the cathode materials and the electrochemical performance of the Li-S batteries and the critical research directions needed for lithium sulfur batteries to be addressed are summarized.