Progress and Prospects of Emerging Potassium-Sulfur Batteries

The potassium-sulfur battery (K-S battery) as an innovative battery technology is a promising candidate for large-scale applications, due to its high energy density and the low cost of both K and S. The development of the K-S technology is, however, inhibited by its low reversible capacity and the safety issues related to the K metal anode. Here, the review starts by discussing the mechanism of the redox reactions for the K-S batteries and emphasizes the challenges for this battery system based on its current research status. Furthermore, the current improvement strategies for the K-S system in terms of the sulfur cathode, electrolyte, separator, and K metal anode are summarized. Finally, future perspectives on the development of the K-S system are proposed.