Low-temperature Ni particle-templated chemical vapor deposition growth of curved graphene for supercapacitor applications

Atmospheric pressure chemical vapor deposition (APCVD) using gas phase carbon sources, e.g. methane, has been shown to yield high-quality graphene with excellent reproducibility. So far high temperatures, typically between 900 and 1000 degrees C, are widely adopted for such deposition process. In this work, we demonstrated that the deposition temperature can be reduced to 650 degrees C when using micron-sized Ni particles as the template/catalyst to produce curved graphene. The effects of growth temperature and particle size were systematically studied and correlated with previous theoretical models on graphene growth. The results suggest that the low temperature growth is enabled by the large amount of atomic step edges present at the Ni particle surface, which facilitate methane decomposition, graphene formation and defect healing. The curved graphene was used as an electrode material and demonstrated a specific capacitance of 203.4 F g(-1) in KOH electrolyte. Two-electrode supercapacitor constructed with the curved graphene also showed outstanding electrochemical properties, such as high energy density (40.9 Wh kg (1)) and power density (70 kW kg (1)), as well as long-term stability. (C) 2015 Elsevier Ltd. All rights reserved.