Manipulating metal-sulfur interactions for achieving high-performance S cathodes for room temperature Li/Na-sulfur batteries

Rechargeable lithium/sodium-sulfur batteries working at room temperature (RT-Li/S, RT-Na/S) appear to be a promising energy storage system in terms of high theoretical energy density, low cost, and abundant resources in nature. They are, thus, considered as highly attractive candidates for future application in energy storage devices. Nevertheless, the solubility of sulfur species, sluggish kinetics of lithium/sodium sulfide compounds, and high reactivity of metallic anodes render these cells unstable. As a consequence, metal-sulfur batteries present low reversible capacity and quick capacity loss, which hinder their practical application. Investigations to address these issues regarding S cathodes are critical to the increase of their performance and our fundamental understanding of RT-Li/S and RT-Na/S battery systems. Metal-sulfur interactions, recently, have attracted considerable attention, and there have been new insights on pathways to high-performance RT-Li/Na sulfur batteries, due to the following factors: (1) deliberate construction of metal-sulfur interactions can enable a leap in capacity; (2) metal-sulfur interactions can confine S species, as well as sodium sulfide compounds, to stop shuttle effects; (3) traces of metal species can help to encapsulate a high loading mass of sulfur with high-cost efficiency; and (4) metal components make electrodes more conductive. In this review, we highlight the latest progress in sulfide immobilization via constructing metal bonding between various metals and S cathodes. Also, we summarize the storage mechanisms of Li/Na as well as the metal-sulfur interaction mechanisms. Furthermore, the current challenges and future remedies in terms of intact confinement and optimization of the electrochemical performance of RT-Li/Na sulfur systems are discussed in this review.