N-doped porous carbon nanotubes derived from polypyrrole for supercapacitors with high performance

N-doped porous carbon nanotubes (NCNs-A) were successfully prepared by a scalable and straightforward mixed salts (NaCl/ZnCl2) activation method with carbon precursor of polypyrrole (PPy). The independent salt NaCl or ZnCl2, the dosage of mixed salts, and the carbonization temperature all have a strong effect on the final products. ZnCl2 is the key activator for activation, and with an increase of the mixed salts, the surface area of NCNs-A is increased. However, excess salt can lead to a decrease in the surface area. Additionally, a suitable carbonization temperature also increases the surface area. The results indicate that optimal synthesis conditions are a mixed salts mass ratio of 2 and a carbonization temperature at 800℃. During the carbonization process, the mixed salts as combined porogen and template ensure the obtained NCNs-A possesses tubular morphology derived from PPy, abundant porous architecture, a high specific surface area of 1278 m2 g−1 and a high nitrogen doping of 9.26 at%. When used as electrode material for the supercapacitor, the NCNs-A achieved an outstanding electrochemical performance.