High-performance nitrogen-doped porous carbon materials derived from waste biomass for supercapacitors

Abstract

Heteroatom-doped porous carbon materials have gained extensive application as electrode materials for supercapacitors. Nitrogen-doped porous carbon materials (NPPCPC-y) were prepared using dicyandiamide as the nitrogen dopant and the husk of Physalis (Physalis pubescens L.) as the carbon source. NPPCPC-1 exhibits a nitrogen content of 11.28 % and a specific surface area of 1677.19 m²·g⁻¹. Notably, NPPCPC-1 demonstrates excellent capacitance performance of 255.9 F·g⁻¹ at 50 A·g⁻¹ and high rate capability of 387.9 F·g⁻¹ at 0.5 A·g⁻¹. In a two-electrode system, NPPCPC-1//NPPCPC-1 exhibits a wide operating voltage range of 2.2 V in 1 M Na₂SO₄, delivering an energy density exceeding 30 Wh·kg⁻¹ (1100 W·kg⁻¹). Additionally, the NPPCPC-1//NPPCPC-1 undergoes 20,000 continuous charge-discharge cycles (10 A·g⁻¹ in KOH electrolyte) while maintaining a capacitance retention of over 99 %.