Lithium/sulfur batteries with high specific energy: old challenges and new opportunities.

In this review, we begin with a brief discussion of the operating principles and scientific/technical challenges faced by the development of lithium/sulfur cells. We then introduce some recent progress in exploring cathodes, anodes, and electrolytes for lithium/sulfur cells. In particular, several effective strategies used to enhance energy/power density, obtain good efficiencies, and prolong cycle life will be highlighted. We also discuss recent advancements in techniques for investigating electrode reactions in real time and monitoring structural/morphological changes of electrode materials under cell operating conditions to gain a better understanding of the mechanistic details of electrode processes. Finally, the opportunities and perspective for future research directions will be discussed.