Synthesis of nitrogen-doped plasma treated carbon nanofiber as an efficient electrode for symmetric supercapacitor

A nitrogen-doped plasma treated carbon nanofiber is prepared by using melamine and ambient plasma for supercapacitor applications. Nitrogen of 11 wt% was doped, and electrochemical active surface area increased by almost four times, compared to precursor CNF, resulting that high specific capacitance of 495 Fg−1 at 0.5 Ag−1, which is more than six times larger than 73 Fg−1 of CNF, with remarkable rate capability and cyclic stability was obtained. Electrochemical impedance is also dramatically reduced from 249 to 24 Ω at 100 Hz. Specific energies of 21 Whkg−1 and 12.2 Whkg−1 at the specific power of 200 Wkg−1 and 4,000 Wkg−1, respectively, were obtained with high capacitance retention (94%) and coulombic efficiency (92%) after 10,000 cycles. The results demonstrate that the as-prepared electrode can be a good alternative electrode material for stable and reliable supercapacitors.