Redox‐Active Organic Sodium Anthraquinone‐2‐Sulfonate (AQS) Anchored on Reduced Graphene Oxide for High‐Performance Supercapacitors

Abstract Redox active organic quinones are potentially low cost, sustainable, and high‐energy pseudocapacitive materials due to their fast and reversible redox reactivity. However, their electrically insulating nature prevents any practical application. Herein, for the first time, sodium anthraquinone‐2‐sulfonate (AQS) is examined as an organic redox‐active compound and highly conductive graphene nanosheets are incorporated to enhance the electronic conductivity. The SO 3 − functional group of AQS offers excellent hydrophilicity, which promotes the molecular level binding of AQS with reduced graphene oxide (rGO) and leads to a 3D interconnected xerogel (AQS@rGO). The composite exhibits a high specific capacitance of 567.1 F g −1 at 1 A g −1 with a stable capacity retention of 89.1% over 10 000 cycles at 10 A g −1 . More importantly, the optimized composite maintains a high capacitance of 315.1 F g −1 even at 30 A g −1 due to the high pseudocapacitance of AQS and the capacitive contribution of rGO. First‐principles calculations further elucidate that AQS offers strong adhesion to rGO sheets with the formation of a space‐charge layer, which is favorable for the pseudocapacitance of AQS. This work opens a new avenue for developing high‐performance supercapacitors though rational combination of redox organic molecules with highly conductive graphene.