Facile synthesis of nitrogen-doped interconnected porous carbons derived from reed and chlorella for high-performance supercapacitors

Three-dimensionally (3D) nitrogen (N)-doped interconnected porous carbons (IPC) derived from cost-effective biomasses were facilely prepared by one-step method and utilized as electrochemical double layer capacitor (EDLC) electrodes. The reed and chlorella derived interconnected porous carbons (denoted as IPC-R and IPC-C) through carbonization with chemical activation both exhibited typical capacitive behaviors; importantly, by introducing N-rich chlorella into N-free reed by interactive‑carbonization, the resultant N-doped interconnected porous carbons (IPC-RC) positively demonstrated a high N content, a large specific surface area and pore volume as well as a high graphitization, which are crucial for fast ion diffusion and thus enhancing the electrochemical properties of supercapacitor. In the three-electrode system, the IPC-RC1.2 showed a superb specific capacitance of 340.4 F/g at a current density of 1 A/g, one of the highest capacitances for biomass derived‑carbon electrodes reported so far. Even at 20 A/g, the capacitance could achieve 265.5 F/g, revealing the superb rate capability. In the symmetric two-electrode system, the maximum power density and energy density reached up to 23.6 Wh/kg and 15,000 W/kg, respectively. Besides, an outstanding cycling stability was observed after 10,000 cycles.