A First Principle Study of Graphene/Metal-Oxides as Nano-Composite Electrode Materials for Supercapacitors

The present study is about diamond shaped clusters (quantum dots) of CuO and Fe2O3, which are adsorbed physically on graphene substrates to develop electrode materials for supercapacitor applications. Density functional theory (DFT) calculations based on the generalized gradient approximation, of Perdew, Burke and Ernzerhof, along with a hybrid functional have been performed to investigate formation energy, electronic structure parameters and isosurface electronic charge density of CuO/graphene and Fe2O3/graphene composite systems. The calculated values of formation energy for CuO/graphene and Fe2O3/graphene composite systems are 0.14eV and 3.7eV, respectively. Isosurface electronic charge density calculations depict the charge transfer mechanism between cluster structure and the graphene substrate. Electronic properties and isosurface electronic charge density results confirm more conducting behavior of CuO/graphene in comparison with the Fe2O3/graphene composite system. From this DFT study, it is inferred that CuO/graphene provides an extra scaffold for electrochemical performance.