Recent advances of metal phosphides for Li–S chemistry

Li–S batteries have been considered as one of advanced next-generation energy storage systems owing to their remarkable theoretical capacity(1672 m Ah g-1) and high energy density(2600 Wh kg-1). However,critical issues, mainly pertaining to lithium polysulfide shuttle and slow sulfur reaction kinetics, have posed a fatal threat to the electrochemical performances of Li–S batteries. The situation is even worse for high sulfur-loaded and flexible cathodes, which are the essential components for practical Li–S batteries. In response, the use of metal compounds as electrocatalysts in Li–S systems have been confirmed as an effective strategy to date. Particularly, recent years have witnessed many progresses in phosphidesoptimized Li–S chemistry. This has been motivated by the superior electron conductivity and high electrocatalytic activity of phosphides. In this tutorial review, we offer a systematic summary of active metal phosphides as promoters for Li–S chemistry, aiming at helping to understanding the working mechanism of phosphide electrocatalysts and guiding the construction of advanced Li–S batteries.