High-performance N-doped activated carbon derived from walnut green peel for supercapacitors.

Activated carbon materials derived from biomass for supercapacitors have received great attention due to their natural abundance and low cost. The agricultural waste walnut green peel can be a promising activated carbon electrode material and resource utilization of it would effectively alleviate the environmental pollution problem. Here we reported the N-doped activated carbon materials (N/ACs) from walnut green peel using melamine as the nitrogen source. N/ACs showed obvious pore structure, high specific surface area, low resistance, and fast charge transfer rate. Thereinto, the optimized N/AC-2 showed the most excellent and better capacitive performance, with the specific capacitance of 304.5 F g⁻¹ at 0.5 A g⁻¹. N/AC-2 exhibited high energy density (40.05 W h kg⁻¹) and power density (22.5 kW kg⁻¹) as the supercapacitor electrode. In addition, the capacitance retention rate of N/AC-2 remained 95.2% after 3000 cycles at 10 A g⁻¹. Our work demonstrated that the prepared N/ACs would be more promising electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]