Recent development of metal compound applications in lithium-sulphur batteries

Lithium-sulphur (Li-S) batteries are one of the most promising candidates for the next generation of energy storage systems to alleviate the energy crisis. However, Li-S batteries' commercialization faces the challenges of low active materials utilization, poor cycling life, and low energy density. Recently, tremendous progress has been achieved in improving the electrode performances and tap density by using the nanostructured metal compounds in Li-S batteries. In this review, we not only present the latest various nanostructured metal compounds applications in Li-S batteries, including metal oxides, metal sulphides, metal carbides, metal nitrides, and metal organic frameworks, but also we focus on the interaction mechanisms between these polar metal compounds with polysulphides. The issues and bottlenecks of these metal compounds are concluded and the corresponding available solutions to address these issues are proposed. This systematic discussion and proposed strategies can offer avenues to the practical application of Li-S batteries in the near future.