A review of electrolytes for lithium–sulphur batteries

•Review the current trends of research and development of Li/S electrolytes.•Discuss how new concepts and materials contribute to solve Li/S cell problems.•Discuss how the selection of Li-salt should be better motivated.•Suggest/recommend approaches to better understand Li/S electrolyte functionality.

To optimize the electrolyte is one of the most important directions to take in order to improve the Li/S battery in terms of performance – especially cell cyclability, rate capability, safety, and life-span. In this review we examine the state of the art for different choices of electrolytes; concepts, design, and materials, and how the resulting chemical and physical properties of the electrolyte affect the overall Li/S battery performance. The objective is to create an overall assessment of electrolytes in use at present and to provide a thorough basis for rational selection of future electrolytes for Li/S batteries.