2,6-diaminoanthraquinone-functionalized S,N-codoped graphitic biomass carbon as advanced electrode materials for supercapacitors

Supercapacitors have rapidly become an important electrochemical energy storage system due to their advantages such as fast power delivery, fast charging, and long cycle life, and play a dominant role in the field of high power transmission or absorption. Among various electrode materials, biomass carbon exhibits exciting electrochemical properties and impressive prospects owing to its wide availability, environmentally friendly renewability, and low-cost electricity storage. In this work, we report sulfur/nitrogen-doped biomass carbon with covalently grafted anthraquinone organic small molecules on its surface, derived from banana leaves (DAAQ-S/N-C-850). The prepared DAAQ-S/N-C-850 electrode material exhibits a high specific capacitance value of 355.3 F g−1 at a current density of 5 mV s−1 in three-electrode system. The experimental results show that the double doping of S and N can effectively improve the electrical conductivity of the electrode material, and the synergy between DAAQ organic molecules and double doping can availably improve the pseudocapacitive performance of the electrode material. Moreover, the asymmetric supercapacitor of DAAQ-S/N-C-850//CNT@RGO achieves energy density (30.9 Wh kg−1) and power density (0.714 kW kg−1) in 1 M H2SO4 electrolyte. This article proposes functionalized S/N-doped biomass carbon and provides a novel method for the application of biomass carbon in the field of energy storage.