Oxygen–nitrogen–sulfur self-doping hierarchical porous carbon derived from lotus leaves for high-performance supercapacitor electrodes

3D porous carbon is successfully fabricated from lotus leaves, an abundant and renewable biomass, via a facile and easy-scale up route of carbonization and successive activation by mechanically mixing with KOH. The as-prepared carbon possesses high surface area (3601 m2/g), hierarchical porous structure with interconnected micro/meso/macropores and good level of O–N–S heteroatoms doping. These admirable features endow beneficial multiple synergistic effects for high-performance supercapacitor electrode. The as-obtained carbon exhibit an ultra-high specific capacitance of 523 F/g at 1 A/g in a three-electrode system and 294 F/g at 1.0 A/g in a two-electrode system in 6 mol/L KOH electrolyte with high rate performance of ~85% retention from 1 to 10 A/g and outstanding cycling stability of ~99% capacitance retention after 10000 cycles. These values indicate a high-performance biomass-derived carbon as supercapacitor electrode and may boost the large-scale application of 3D porous carbons doped by heteroatoms for energy storage.