Synergistic effect of heteroatom-doped activated carbon for ultrafast charge storage kinetics

Providing a crystallographic and electronic modification of carbon-based materials in electrical double-layer capacitors (EDLCs) is an essential technology needed to improve the charge storage kinetics and to enhance ultrafast cycling performances. However, despite numerous structural composite and morphological modification efforts focused on active materials, ultrafast charge storage kinetics still indicated a poor ultrafast capacitance and low cycling stability. To solve these problems, in the present study, we propose a novel heteroatom (N, P, and B)-doped activated carbon (AC) that has the synergistic effects of N-, P-, and B-doping using the one-pot doping calcination process. Compared to the bare-AC, N-doped AC, P-doped AC, and B-doped AC, the novel heteroatom-doped AC indicates an improved ultrafast charge storage kinetics, such as high specific capacitance (243.9 F g ⁻¹ at the scan rate of 10 mV s ⁻¹ ), good cycling stability (216.7 F g ⁻¹ at 100 mV s ⁻¹ after 500 cycles), and superb ultrafast cycling capacitance (199.7 F g ⁻¹ at 300 mV s ⁻¹ ). These superb electrochemical performances can be attributed by synergistic effects of increased active sites by N-doping related to a high charge storage area, improved functional groups by P-doping related to an excellent wettability between the electrode and the electrolyte, and enhanced electrical properties by B-doping related to a good electron acceptability.