Sulfur Copolymer: A New Cathode Structure for Room-Temperature Sodium–Sulfur Batteries

Abstract

High-energy electrochemical storage containing earth abundant materials could be a choice for future battery development. Recent research reports indicated the possibility of room-temperature sodium-ion–sulfur chemistry for large storage including smart grids. Here, we report a room-temperature sodium–sulfur battery cathode that will address the native downsides of a sodium–sulfur battery, such as polysulfide shuttling and low electrical conductivity of elemental sulfur. In this Letter, we use a sustainable route which ensures a large sulfur confinement (i.e., ∼90 wt %) in the cathode structure. The sulfur-embedded polymer is realized via thermal ring-opening polymerization of benzoxazine in the presence of elemental sulfur (CS90) and later composite with reduced graphene oxide (rGO). The resulting CS90 allows a homogeneous distribution of sulfur due to in situ formation of the polymer backbone and allows maximum utilization of sulfur. This unique electrode structure bestows CS90–rGO with an excellent Cou...