2 D amorphous frameworks of NiMoO4 for supercapacitors: defining the role of surface and bulk controlled diffusion processes

This study demonstrates a novel approach by which amorphous nickel molybdate nanoflakes were processed into high surface area electrodes for supercapacitors. Time dependent studies showed evolution of flake-like morphology from anisotropic nuclei particles exhibiting high redox activity. An intrinsic correlation between the surface area, specific capacitance and the internal resistance has been deduced and explained on the basis of relative contributions from the faradic reactions of NiMoO4. Relative contributions from the bulk and surface processes were mathematically modeled. The electrodes exhibited specific mass capacitance values as high as 1650 F g−1 which is the highest reported value so far. Coin cells employing these rechargeable electrodes were also demonstrated exhibiting an energy and power density of 92 W h kg−1 and 23 kW kg−1, respectively, with excellent cyclic stability.