  Herein, we report a improved method for the physical grafting of
1-nitropyrene (Pyr-NO2) onto highly graphitized carbon onion. This is achieved
through a lowering of the onset potential of the pyrene polymerization via in
situ reduction of the NO2 group. The additional redox activity pertaining to
the reduced NO2 enables exceeding the faradaic capacity which is associated
with the p-doping of the grafted pyrene backbone, as observed for pyrene,
1-aminopyrene, and unreduced Pyr- NO2. Theoretical calculations demonstrate the
charge transfer and binding enthalpy capabilities of Pyr-NO2, which are
significantly higher than those of the other two species, and which allow for
improved p-stacking on the carbon surface. Upon 20 wt % grafting of Pyr-NO2,
the capacity of the electrode jumps from 20 mAh g-1 electrode to 38 mAh g-
electrode, which corresponds to 110 mAh g-1 per mass of Pyr-NO2 and the average
potential is increased by 200 mV. Very interestingly, this high performance is
also coupled with outstanding retention with respect to both the initial
capacity for more than 4000 cycles, as well as the power characteristics,
demonstrating the considerable advantages of employing the present in situ
grafting technique.
