Pseudocapacitive Materials for Metal-Sulfur Batteries

Alkali metal-sulfur batteries have developed profound interest among researchers due to their high theoretical energy density (>2500 Wh kg−1). However, their commercial exploitation potential is hindered due to the lower electronic conductivity of sulfur and other discharging products, deteriorating polysulfide shuttling, and substantial volume variations during discharging. Pseudocapacitive materials can address these issues. Their superior intrinsic properties, such as higher electronic conductivity, better ionic conduction, and abundant functional groups that, trap polysulfides and make them suitable candidates for batteries. Pseudocapacitive materials such as layered transition metal oxides (TMOs), phosphides (TMPs), chalcogenides (TMCs), MXenes, etc. have the metal center acting as Lewis’s entity to attract polysulfide anions. In contrast, the anionic species, such as oxides/phosphides and chalcogens, react with metal ions (Li, Na, and K) to provide the synergetic effect. This chapter discusses the benefits of using these materials for metal-sulfur batteries and associated challenges in a detailed manner.