Potassium-sulfur batteries: Status and perspectives

This review article aims to provide insight into the research status of the potassium-sulfur (K-S) system, feature the challenges facing this technology, and present possible research directions for the realization of its practical applications. We begin with an introduction to the fundamental electrochemistry of K-S batteries and emphasize the distinctions between K-S technology and the well-established lithium-sulfur (Li-S) system. Then, we focus on the development of the materials involved in K-S batteries in terms of cathodes, K anodes, and various electrolyte systems. Finally, we provide several possible research directions to make the K-S system a reality, with the emphasis, from our point of view, on the attempts to construct practical parameters for K-S batteries by adopting the critical metrics of the current Li-S system.