Enhanced Capacitive Performance of N-Doped Activated Carbon from Petroleum Coke by Combining Ammoxidation with KOH Activation

Low cost with high specific capacitance and energy density is the critical and main requirement for practical supercapacitors. A novel N-doped activated carbon was fabricated by KOH activation of petroleum coke and ammonia treatment. The as-prepared carbon exhibits a high specific surface area (1875 m(2) g(−1)), excellent conductivity (57 S m(−1)), and rich nitrogen level (4.0 wt%). Those outstanding characters result in this porous carbon a hopeful electrode material for electrochemical supercapacitors. It shows high specific capacitance (up to 299 F g(−1)) and superior rate capability (76 % retention ratio at 20 A g(−1)) in 30 wt% KOH aqueous electrolyte. This efficient treatment method ensures its prosperous application in energy storage systems.