▎ 摘　　要

To synthesize graphene built up from fewer layers with more defects, it was grown by chemical vapor deposition (CVD) and cooled to ambient temperatures at different cooling rates with different volume flow rates of hydrogen. Then, to add nitrogen functional groups to the surface of graphene, it was treated by radio frequency (RF) nitrogen plasma at different power levels and periods of time. The faster the cooling rate, the higher the specific capacitance. Furthermore, the specific capacitance reached a maximum (150.5 Fg(-1)) at the nitrogen-plasma treatment conditions (power = 100 W and period of time = 30 min). A longer periods of time and higher power resulted in higher specific capacitance except for 150 W at 30 min. (C) The Electrochemical Society of Japan, All rights reserved.