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

• Published in: Energy technology (Weinheim, Germany) Germany), 2020-05, Vol.8 (5), p.n/a
• Main Authors: Liao, Ming Dong, Peng, Chuan, Hou, Sheng Ping, Chen, Jian, Zeng, Xian Guang, Wang, Hao-Lun, Lin, Jarrn-Horng
• Format: Article
• Language: English
• Subjects: Acetylene; Activated carbon; activated carbon fibers; Capacitance; Carbon fibers; Catalysts; Copper converters; Electrode materials; Electrodes; Flux density; Melamine; Nanofibers; Nitrogen; nitrogen doped; Potassium; Potassium hydroxides; Pyrolysis; Size distribution; Sodium sulfate; Specific surface; Supercapacitors; Surface area
• ISSN: 2194-4288; 2194-4296
• DOI: 10.1002/ente.201901477

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. Nitrogen‐doped activated carbon nanofibers (N‐ACF) demonstrate excellent electrochemical performance with a specific capacitance value of 227 F g−1 at 0.5 A g−1, and show a 94% capacitance retention after 10 000 cycles at 2 A g−1. Moreover, N‐ACF‐based electrode displays a high energy density of 14.30 Wh kg−1 and a high power density of 79.88 W kg−1.