Sulfonated porous carbon nanosheets derived from oak nutshell based high-performance supercapacitor for powering electronic devices

In this work, we report sulfonated porous carbon nanosheets (SPC) derived from waste oak nutshell withered from acorn trees for supercapacitor electrodes. The SPC is synthesized via facile acidic hydrothermal pre-carbonization to retain robust carbon network followed by KOH activation to achieve porous carbon. The detailed material characterization reveals that the optimized SPC possesses micro-mesopores distribution with sulfur doping and partially graphitized carbon. The optimized SPC as a supercapacitor electrode delivers excellent specific capacitance of 398 F g−1 (0.4 A g−1) in a three-cell electrode and exhibits an outstanding energy density of 17 Wh Kg−1 (200 W kg−1) with remarkable 97% capacitance retention after 10000 cycles in symmetric supercapacitor cell. The superior performance is ascribed to the heteroatom doping, interconnected porous carbon network, and mesopore inclusion. Moreover, the symmetric cell exhibits 98.5% retention of capacitance after 10000 cycles in the neutral electrolyte, indicating its high electrochemical stability of carbon framework. Also, it can power a 3.5 V commercial green light-emitting diode (LED) for 5 min successfully. The sustainable strategy of producing doped porous carbon with impressive specific capacitance, outstanding cyclic stability, and capability of powering electronic device demonstrates its promising potential towards high-valued energy storage material