Nitrogen-doped mesoporous carbon/poly-o-phenylenediamine composites for high-performance hybrid supercapacitor electrodes

Nitrogen-doped mesoporous carbon/poly-o-phenylenediamine composites (denoted as N-MC/PoPD) were successfully synthesized by sacrificial hard template method followed by in situ oxidation polymerization initiated by FeCl3. It is revealed that the resultant N-MC/PoPD composites still remained original graphitization structure and narrow pore size distributions (centered at similar to 3.8 nm) but suffered visibly monotonical decrease in specific surface area after oPD was increasingly polymerized onto N-MC with an increase of the mass ratio of PoPD to N-MC from 1:1 to 5:1. As supercapacitor electrode measured by galvanostatic charge-discharge in 6 mol L-1 KOH, a volcano curve was found when plotting specific capacitance of the N-MC/PoPD versus the mass ratio of N-MC to oPD; the N-MC/PoPD(2:1) with moderate surface area and the highest electrochemical conductivity delivered the highest specific capacitance of 229 F g(-1) at a current density of 1 A g(-1), which is twice of that obtained on the single N-MC with the maximum surface area. The remarkable enhancement in specific capacitance could be ascribed to the synergistic effect between two components of N-MC and PoPD.