A composite-hydroxide-activation strategy for the preparation of N/S dual-doped porous carbon materials as advanced supercapacitor electrodes

Nitrogen and sulfur co-doped hierarchical porous carbon has gained enormous attention in energy storage field owing to its high capacitance and chemical stability. Herein, nitrogen and sulfur co-doped hierarchical porous carbon derived from ginkgo leaves is fabricated via carbonization followed by a facile composite-hydroxide-activation (CHA) strategy for supercapacitors application. The resultant carbon features sheet-like structures with hierarchical pores, possessing specific surface area (1975 m² g⁻¹), micropore volume (0.62 cm³ g⁻¹), and higher heteroatom content up to 1.88% (N element) and 1.87% (S element). Due to its compositional and structural advantages, the nitrogen and sulfur co-doped hierarchically porous carbon exhibits a high specific capacitance of 333.4 F g⁻¹ (at 0.1 A g⁻¹) and an excellent rate capability (277.5 F g⁻¹ at 20 A g⁻¹). A superior cycling stability can be obtained as well with 94.4% capacitance retention after 10,000 cycles at 5 A g⁻¹. In addition, the XPS result confirms that CHA strategy could be effective to fix heteroatoms into the primarily aromatic carbon backbone. The present study demonstrates an effective and universal strategy to develop high-performance hierarchical porous carbon from biomass for energy storage devices.