Using Asphaltene Supermolecules Derived from Coal for the Preparation of Efficient Carbon Electrodes for Supercapacitors
journal contributionposted on 06.07.2016, 00:00 by Wen-Hui Qu, Yu-Bo Guo, Wen-Zhong Shen, Wen-Cui Li
Asphaltene supermolecules extracted from coal consist of highly condensed polyaromatic units and peripheral aliphatic chains, which is a natural source with high carbon content. In this study, we demonstrate that the asphaltene can be used as an ideal supermolecular carbon precursor for the fabrication of carbon nanosheets by self-assembly via π–π and hydrogen bonding interactions with a sheet-structure-directing agent of graphene oxide. The overall thickness of the obtained asphaltene based carbon nanosheets can be tuned from 13 ± 3 to 41 ± 5 nm. These carbon nanosheets show an electrical conductivity of ca. 450 S m–1. When they are used as electrode materials for supercapacitors, the carbon nanosheets demonstrate a specific capacitance of 163 F g–1 even at a current density of 30 A g–1 tested in a three-electrode system, due to high electrically conductive networks and short diffusive paths. The maximum specific gravimetric capacitance and surface area-normalized capacitance in two-electrode system are 191 F g–1 and 43 μF cm–2, respectively, indicating very high utilization of the available surface area. These results prove that asphaltene is a promising molecular precursor for the preparation of energy materials, further displaying an efficient route for staged conversion of coal that is abundant in nature.