Nano-porous carbon materials derived from different biomasses for high performance supercapacitors

Nano-porous carbon materials derived from various natural plants are fabricated by a facile, cost-effective and efficient approach. The influence of well-dispersed intrinsic elements in different precursors and chemical activation process under different temperatures on the morphology, surface chemistry, textural structures and electrochemical performance have been studied and analysed in detail. These as-prepared nano-porous carbons possess high accessible surface area (685.75–3143.9 m² g⁻¹), well-developed microporosity and high content of naturally-derived heteroatom functionalities (16.43 wt%). When applied as electrode materials for supercapacitors in a three-electrode system with 6 M KOH, the obtained nano-porous carbons derived from lotus leaves at 700^oC possess a high specific capacitance of 343.1 F g⁻¹ at 0.5 A g⁻¹ and a capacitance retention of 96.2% after 10000 cycles at 5 A g⁻¹. The assembled symmetrical supercapacitor presents a high energy density of 24.4 Wh kg⁻¹ at a power density of 224.6 W kg⁻¹ in Na₂SO₄ gel electrolyte. This work provides guiding function for unified and large-scale utilization of agricultural biomass waste. The obtained sustainable activated carbon products can be used in diverse applications.