Alloys to Replace Mg Anodes in Efficient and Practical Mg-Ion/Sulfur Batteries

The development of rechargeable Mg/S batteries is driven by the design of reliable electrolytes. To date, they seem not suitable for industrial transfer as they are either corrosive or necessitate a complex formulation. The innovative strategy reported here, which replaces magnesium by Mg alloys at the negative electrode, enables employing facile electrolyte formulations as well as proposes an easier electrode-shaping process. As a proof-of-concept, Mg3Bi2/S cells were evaluated with simple Mg(TFSI)(2)/DME electrolyte. Electrochemical mechanisms including Mg3Bi2 dealloying and sulfur magnesiation were probed by X-ray diffraction and Xray photoelectron spectrocsopy, respectively. In addition, very promising cycling performance at elevated current density is obtained. These preliminary findings pave the way for additional improvements toward further practical applications.