Carbon materials for Na-S and K-S batteries

Global energy demand is rapidly increasing, and it undoubtedly reflects the importance of high-capacity energy storage systems based on Earth’s abundant resources. The practicality of lithium-ion batteries for large-scale energy storage is less likely to be viable due to the limited sources of lithium and their uneven geographical distribution. Because of the Earth’s abundance of sodium and potassium as well as rich sulfur electrochemistry involving multi-electron transfer, sodium-sulfur (Na-S) and potassium-sulfur (K-S) batteries are promising candidates for large-scale energy storage applications. This review highlights the fundamental battery chemistries and challenges of Na-S and K-S batteries. It discusses the design strategies of cathode, anode, and separator with a focus on the utilization of carbon materials, highlighting the crucial role of carbon in tackling the challenges. Finally, future perspectives are provided, and plausible directions are outlined for the further advancement of Na-S and K-S batteries.