Performance Enhancement and Mechanistic Studies of Magnesium–Sulfur Cells with an Advanced Cathode Structure

Magnesium–sulfur cells based on abundant, safe Mg and S are demonstrated with a cathode containing a preactivated carbon nanofiber (CNF) electrode matrix filled with sulfur active material and a CNF-coated separator. The CNF coating on the separator serves as a polysulfide trapper and an upper current collector for facilitating high sulfur utilization and enhancing the cycle life. Mechanisms regarding the performance enhancement and the charge–discharge processes of the Mg–S cells are investigated with spectroscopic, microscopic, and electrochemical analyses.