Figure 5: FeOx/graphene hybrid as an anode material for the ultra-Ni–Fe battery.

(a) CV curves of FeOx/graphene hybrid at various scan rates in 1 M KOH. (b) Average specific capacity of FeOx nanoparticles grown on graphene at various scan rates based on CV data in (a). (c) Average specific capacitance within a voltage range of 1.2 V (from −0.2 V to −1.4 V vs SCE) of FeOx nanoparticles grown on graphene at various scan rates based on CV data in (a). (d) Cycling stability of the FeOx/graphene hybrid over 300 CV cycles at 40 mV s−1. Loading of FeOx/graphene was ~0.7 mg cm−2 for the electrode.