Gelatinization assisted synthesis of multi-heteroatoms enriched 3D honeycomb-like porous carbon for high-voltage supercapacitor device

Developing high-performance supercapacitors with low-cost electrode materials that possess high power energy while maintaining high specific energy is highly desirable and remains a major challenge. Herein, we report an N, S, P-multi-heteroatom co-doped three-dimensional (3D) honeycomb-like porous carbon nanosheets from garden cress seeds via facile two-step synthesis strategy involving gelatinization accompanied by KOH activation. The large specific surface area (1302.3 m(2) g(-1)) and hierarchical porous structure has advantages of a well-balanced 3D interconnected micro-/meso-/ and macropores for shorter ion pathway and provide rapid electrolyte penetration. When the as-obtained doped porous carbon is used as a supercapacitor electrode, it delivered high specific capacitance of 409 F g(-1) and 279 F g(-1) in aqueous three and two-electrode configuration, respectively. In addition, the device shows high cyclic stability of 93% even after 10,000 cycles. More importantly, the assembled symmetric supercapacitor device using 1 M tetraethylammonium tetrafluoroborate (TEABF4) as organic electrolyte (2.8 V) delivered outstanding specific energy of 31 Wh kg(-1) (6.2 Wh L-1) at a specific power of 1300 W kg(-1) (260 W L-1) and retained 25 Wh kg(-1) even at a high specific power of 3000 W kg(-1). Notably, the high voltage fabricated supercapacitor was able to power up various light-emitting diodes of voltage range from 1.8 to 3.8 V demonstrating its potential towards powering electronic devices. The strategy to employ cost-effective renewable garden cress seeds as biomass precursors to achieve hierarchical porous multi-heteroatom doped 3D carbon is of great interest for high-performance energy storage applications.

Automated summary

The study introduces a strategy involving garden cress seeds to create N, S, P-multi-heteroatom co-doped 3D porous carbon nanosheets with high specific surface area and hierarchical porous structure for supercapacitor electrodes. The resulting supercapacitor device exhibits high specific energy, specific power, and cycling stability, showing great potential for powering electronic devices.