Fundamental Understanding and Material Challenges in Rechargeable Magnesium–Sulfur Battery: Current Advances and Perspective

Rechargeable magnesium–sulfur (Mg–S) batteries have recently aroused broad attention due to their large theoretical energy density, low cost and negligible safety concerns compared to lithium–ion and lithium–sulfur counterparts. Great research efforts have been devoted to exploiting and advancing this Mg–S batteries and endowing them as the competitive alternatives for next-generation energy storage systems. However, the insufficient reversible capacity and rapid capacity loss have severely hindered their practical application due to the inevitable Mg-anode passivation, low sulfur utilization efficiency, polysulfide shuttle effect, and electrode-electrolyte incompatibility. Herein, the efficient modification and improvement strategies are highly required to overcome these challenges. Therefore, it seems significantly necessary to afford a systematical and full review about the recent advancements of Mg–S batteries to promote their farther improvements. In this review, the challenges and recent advances of rechargeable Mg–S batteries are outlined mainly focusing on Mg anode, sulfur cathode, electrolyte and separator. This review is expected to open the new horizons of the design principle of electrode materials, electrolyte and separator to develop highly efficient magnesium–sulfur batteries.