Large‐Scale Synthesis of Nitrogen‐Doped Activated Carbon Fibers with High Specific Surface Area for High‐Performance Supercapacitors

Activated carbon nanofibers (ACFs) with high specific surface area, excellent conductivity, and narrow pore‐size distribution, are regarded as a promising electrode material for high‐performance supercapacitors (SCs). Herein, a facile route to synthesize large‐scale amorphous CF (a‐CF) using catalytic pyrolysis of acetylene (C2H2) at 260 °C over copper catalysts is reported. The conversion rate of acetylene into a‐CF is estimated as high as 72.05 wt%. Subsequently, the as‐prepared a‐CF is transformed into ACFs by potassium hydroxide (KOH) at 800 °C with high specific surface area and porous structures. Moreover, nitrogen‐doped ACFs are conducted in the activation step through a physical mixing of a‐CF/KOH/melamine with various ratios. For SCs, the as‐prepared N‐ACFs display excellent specific capacitance and cycle stability. In the three‐electrode system, the N‐ACF (CF‐03) demonstrates a specific capacitance value of 227 F g−1 at 0.5 A g−1, and shows a 94% capacitance retention after a long cycle (10 000 cycles) at 2 A g−1. Moreover, the CF‐03‐based two‐electrode SC demonstrates a high energy density of 14.30 Wh kg−1 and a high power density of 79.88 W kg−1 in 1 m Na2SO4 electrolyte. Herein, a simple and promising way to prepare large‐scale a‐CF, ACF, and N‐doped ACFs is demonstrated.