Nano cerium oxide (CeO₂) is gaining a lot of attention as an electrochemical energy storage material. However, the crystal plane effects of CeO₂ on energy storage remain largely unexplored. In this regard, two different CeO₂ nano structures: nanoparticles (CNPs) and nanocubes (CNCs) with specifically exposed crystal planes were synthesized by a simple hydrothermal process. Structural characterization using TEM revealed CNPs were enclosed by {111} and {100} surfaces, and CNCs were enclosed by six {100} surfaces. The specific surface areas analyzed estimated by BET for CNPs and CNCs were 44 m²/g and 38.3 m²/g, respectively. The electrochemical properties of the nanostructures were evaluated using cyclic voltammetry and galvanostatic charge-discharge techniques with 3M KOH electrolyte. The experiments revealed that the exposed crystal planes have a more profound effect on the supercapacitance of the nanostructures than the surface area. Despite the slightly lower specific surface area, CNCs dominated by the high energy surface {100} showed considerably higher (69%) specific capacitance than the low energy {111} dominated CNPs. The difference in charge storage between CNCs and CNPs was increasingly wider with the decrease in scan rate. This suggested that the charge storage in CNCs took places both surface and bulk, but was restricted to the surface in CNPs. The difference in charge storage at the surface and bulk were also quantified using electrochemical analysis. Reactivity maps of the nanostructures, generated using molecular dynamics simulation, were in good agreement with our experimental findings. Thus, this study demonstrates how charge storage in supercapacitors can be improved by selecting redox active nanomaterial with highly exposed redox active crystal planes.