Preparation and properties of nickel site doped material Ni1-yXyCo2O4 as supercapacitor materials by in-situ growth method

Abstract

Although NiCo2O4 has been widely applied in supercapacitors, its actual capacity has been limited by the low conductivity and reactivity. Due to the relationship between the performance of the spinel-structured NiCo2O4 electrode material and its microstructure, in this paper, in order to modify the nanostructure of NiCo2O4 to improve its electrochemical performance, hydrothermal method is adopted to synthesize Ni0.98X0.02Co2O4(X = Fe, Cu, Mg, V, Ag, Mn, Mo, Ti) grown on nickel foam. After the synthesis, the physical morphology of the selected Ni0.98Mg0.02Co2O4 and Ni0.98Mn0.02Co2O4 are tested and analyzed by XRD, SEM, XPS and FT-IR. According to the characterization results, it can be found that different kinds of metals are doped in the nickel site of NiCo2O4, and the microscopic morphology of materials is different. It can be seen from the SEM figure that Ni0.98Mg0.02Co2O4 is a small nano-scale particle, while Ni0.98Mn0.02Co2O4 presents rod-like braided structure, and doping at the nickel site does not affect the main structure of the material. It can be seen from EDS data that the atomic ratio and weight ratio of nickel and cobalt elements are consistent with the molecular formula. The XPS spectra of the corresponding elements showed that Ni, Co and O elements were corresponding to NiCo2O4 materials. In conclusion, the result of physical morphology characterization analysis shows that the material is still in standard NiCo2O4 spinel structure.