Exploration of the Unique Structural Chemistry of Sulfur Cathode for High-Energy Rechargeable Beyond-Li Batteries

The increased demand for energy has prompted users to seek alternative energy storage devices. Post-Li-ion battery chemistries have been considered potential contenders for the development of next-generation battery technologies. The high specific capacity (approximate to 1675 mAh g(-1)) and high natural abundance (approximate to 953 ppm) of sulfur provide opportunities to meet the rigorous requirements of the market's demands, such as high energy density and low cost. When combined with a high capacity metal anode (e.g., Na approximate to 1165 mAh g(-1), Mg approximate to 2205 mAh g(-1), and Al approximate to 2980 mAh g(-1)), it leads to high energy density that can outperform the existing battery technologies, including high-energy Li-ion batteries. Despite the unique attributes of the sulfur-based battery system, it remains in infancy owing to the complex reaction chemistry of sulfur cathode, and the level of complexity increases with an increase in valency of metal ions. This review summarizes the unique aspects of a sulfur cathode essential to stabilizing sulfur cathode-based high-energy rechargeable batteries. Furthermore, deeper insight into the electrochemical performance of various metal-sulfur-based systems has been provided. This review may pave the path for the researchers to accelerate the development of sulfur cathode for post-Li-ion batteries.