Sulfur nanocomposite as a positive electrode material for rechargeable potassium–sulfur batteries

A pyrolyzed polyacrylonitrile/sulfur nanocomposite (SPAN) was used as a positive electrode material for a room temperature K–S battery operated in carbonate electrolyte. SPAN presented a high reversible capacity of 270 mA h g−1 (710 mA h gsulfur−1) and excellent rate performance, which demonstrate that it is a promising positive electrode material for K-ion and K-batteries.