N, S co-doped biomass derived carbon with sheet-like microstructures for supercapacitors

In this study, N, S co-doped bamboo fiber derived carbon has been prepared when K₃Fe(CN)₆ and thiourea are selected as graphitization catalysis and dopant, respectively. The derived carbon possesses a large S_BET, suitable graphitization degree, excellent conductivity and wettability of electrolyte, and particularly, it exhibits a unique sheet-like microstructure derived from the layer stripping of gas produced by thiourea pyrolysis, and these microstructure features are very beneficial for energy storage. Typically, the derived carbon displays a high specific capacitance of 328 F/g and an acceptable rate capability of 61.3% at 15 A g⁻¹ in three-electrode systems. Meanwhile, the derived carbon-based coin-type symmetric supercapacitors are assembled in an aqueous electrolyte and an ionic liquid electrolyte, respectively, and they all show a considerable synergetic energy-power output performance (21.2 Wh kg⁻¹ at 454 W kg⁻¹ in aqueous electrolyte, and 61.6 Wh kg⁻¹ at 300 W kg⁻¹ in ionic liquid electrolyte), indicating the potential application of the derived carbon in supercapacitors.