Bifunctional biomass-derived 3D nitrogen-doped porous carbon for oxygen reduction reaction and solid-state supercapacitor

Biomass-derived carbon materials have garnered intensive consideration in energy fields, such as fuel cells and supercapacitors, due to their inexpensive precursors, abundant resources and facile synthesis. Herein, we report a facile strategy based on taro stem precursor to synthesize a 3D nitrogen-doped porous carbon (3DNPC) with micropores, mesopores, macropores, large specific surface area (1012 m² g⁻¹) and nitrogen content (4.8 at%), which displays high catalytic activity and stability for oxygen reduction reaction and good electrochemical properties for supercapacitors. Compared with the commercial Pt/C catalysts, the 3DNPC-800 with 3D porous structure, proper total doped N and high graphitic N content, presents brilliant long-term stability (96.5% retention after 20,000 s) and resistance to methanol crossover for oxygen reduction reaction. With respect to electrode material of supercapacitor, the 3DNPC-800 possesses high specific capacitance (236.4F g⁻¹ at 0.1 A g⁻¹) and outstanding long cycle durability (89.3% retention after 10,000 cycles at 20 A g⁻¹). Moreover, the prepared symmetric solid-state supercapacitor devices achieve outstanding power density (5 kW kg⁻¹ at 5.56 Wh kg⁻¹). Consequently, economically and sustainably utilization nature of materials to fabricate heteroatom-doped carbon materials, having great potential in electrochemical applications, is presented.