Dual‐Interface Regulation for High‐Performance Magnesium–Sulfur Batteries

Abstract Magnesium–sulfur (Mg–S) batteries are promising candidates for high‐energy‐density storage systems, but their performance is critically dependent on the interfacial properties of both the anode and cathode. This study explores a dual‐interface regulation strategy to enhance Mg–S battery performance via tailored electrolyte additives. For the anode, tetrabutylammonium bromide (TBABr) is added to commercially available chlorine‐free Mg(TFSI) 2 ‐based electrolytes, forming a robust bromide‐containing solid electrolyte interphase (SEI) that extend the cycle life of Mg//Mg cells. For the cathode, 1,3,5‐benzenetrithiol (BTT) is introduced as a cathode‐electrolyte interface (CEI) modifier to promote the formation of an organopolysulfide interfacial layer that effectively mitigates polysulfide shuttling. This dual‐interface regulation approach greatly increase the cycle lives of the Mg–S cells and the magnesium–selenium (Mg–Se) cells. This work underscores the importance of a holistic interfacial engineering strategy and provides valuable insights for the development of high‐performance Mg–S batteries.