| Electrochemical supercapacitor (EC) has attracted tremendous attention recently for energy storage application because of its great advantages including high power density, long cycle life and so on. Ordered mesoporous carbon (OMC) with tunable mesopore size and regular channels is considered to be a promising electrode material for investigating the effect of pore structure on ion transport behavior. To develop high value added utilization ways of coal liquefaction residue, OMC electrode materials were synthesized from asphaltene and preasphaltene derived from coal liquefaction residue. The effects of microcrystalline structures, pore structures and surface properties of OMCs on the electrochemical performance were investigated systematically by controlling the carbon sources, templates and synthetic processes. The main achievements are briefly summarized as follows:OMCs were synthesized from asphaltene and preasphaltene via a hard template method, and the electrochemical performances of the as-made OMC materials in supercapacitors were investigated. The results show that the capacitors assembled with the as-prepared OMCs exhibit ideal electric double layer behavior, excellent rate ability and long lifetime. The ion transfer behavior and charge storage capacity greatly depend on the carbon sources and the porous structures of OMCs. OMC with3D bicontinuous cubic symmetry prepared from preasphaltene exhibits the best charge storage ability because of the tortuosity of bicontinuous mesostructure. While, in terms of the ion transfer kinetics, OMC with2D hexagonal symmetry has the best ionic diffusion performance and the lowest impedance for the long pore channels. Furthermore, heat treatment could be a useful way to increase the electrical conductivity and decrease the capacitor impedance. The results showed in the present work have demonstrated the potential of producing OMCs from coal liquefaction residue for energy storage devices, which is of significance for improving the coal liquefaction process and making full utilization of resources.Oxygen-containing functional groups were introduced to asphaltene-based ordered mesoporous carbon (OMC-A) by nitric acid oxidation at mild conditions without damaging pore structures dramatically. The improved specific capacitance of OMC-A is originated from the Faradic redox reaction of oxygen-containing functional groups and enhanced wettability of carbon electrode material. For the modified OMC-A, introduction oxygen-containing functional groups could lead to the increase of specific capacitance without decrease the rate capability of EC, which is more suitable for the application of high power density EC.In order to improve the capacitive behavior and increase the operation voltage, a series of NiO-OMC-A composites with different NiO loadings were prepared by impregnation method. The presence of NiO nanocrystallites was expected to increase the specific surface capacitance from12.6μF·cm-2to18.1μF·cm-2. A capacitor-type||capacitor-type asymmetric electrochemical capacitor based on NiO-OMC-A and OMC-A was assembled in the paper to achieve high energy and power densities, and the effect of mass ratio of NiO-OMC-A and OMC-A on the electrochemical performance was further discussed. The asymmetric capacitor of NiO-OMC-A||OMC-A with a mass ratio of1:1can work in a high voltage region of0～1.4V and exhibits a high energy density of7.4Wh·kg-1with a high power density of189W·kg-1at a scanning rate of10mV·s-1Nitrogen-containing phenolic resin-based OMCs were synthesized directly through a one-pot organic-organic cooperative self-assembly approach by introducing urea to the low-molecular-weight phenolic resin and structure directing agent F127, which is a facile procedure for synthesizing OMC-based materials. The enhanced conductivity, increased charge storage ability and decreased equivalent series resistance are mainly attributed to the nitrogen heteroatoms introduced into carbon structures.
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