Structural and electronic properties of nickel doped cobalt oxide electrode for supercapacitors: A first principle study

Abstract

On the basis of ab initio calculation, we reported the structural and electronic properties of the nickel (Ni) substitution on the cobalt oxide (Co3O4) to produce nickel cobaltite (NiCo2O4) using generalized gradient approximation + U parameter (GGA + U) calculation method. The spinel NiCo2O4 with half-metallic behaviour has a relatively small band gap ∼0.64eV which is spotted decreased from pure Co3O4 band gap 1.26eV. This is due to nickel doping decreased the band gap which also implies that an increase in electrical conductivity. Owing to good electrical conductivity, NiCo2O4 thus enables to be considered for application in supercapacitor. Analysis of the partial density of states (PDOS) shows the differences contributions of cobalt (Co) at the tetrahedral site (Td) and Ni at the conduction bands: Co(Td) ions not affected the majority spin which is in contrast with Ni ions.