Self-Assembled N/S Codoped Flexible Graphene Paper for High Performance Energy Storage and Oxygen Reduction Reaction

A novel flexible three-dimensional (3D) architecture of nitrogen and sulfur codoped graphene has been successfully synthesized via thermal treatment of a liquid crystalline graphene oxide–doping agent composition, followed by a soft self-assembly approach. The high temperature process turns the layer-by-layer assembly into a high surface area macro- and nanoporous free-standing material with different atomic configurations of graphene. The interconnected 3D network exhibits excellent charge capacitive performance of 305 F g^–1 (at 100 mV s^–1), an unprecedented volumetric capacitance of 188 F cm^–3 (at 1 A g^–1), and outstanding energy density of 28.44 Wh kg^–1 as well as cycle life of 10 000 cycles as a free-standing electrode for an aqueous electrolyte, symmetric supercapacitor device. Moreover, the resulting nitrogen/sulfur doped graphene architecture shows good electrocatalytic performance, long durability, and high selectivity when they are used as metal-free catalyst for the oxygen reduction reaction. This study demonstrates an efficient approach for the development of multifunctional as well as flexible 3D architectures for a series of heteroatom-doped graphene frameworks for modern energy storage as well as energy source applications