Preparation of NiCo2O4@CoS heterojunction composite as electrodes for high-performance supercapacitors

It is a preferred method by constructing core - shell structured composites with heterojunctions to enhance the charge transfer and improve electrochemical performances for supercapacitors. In this work, we prepare NiCo2O4@CoS electrode materials on nickel foam via coating n - type CoS on p - type NiCo2O4 to form heterojunctions. The composite shows a synergistic effect from each component and has abundant active sites, as well as outstanding reaction kinetics. Density functional theory (DFT) analysis reveals that the NiCo2O4@CoS composite exhibits higher electronic conductivity than any single component. The NiCo2O4@CoS electrode presents an outstanding capacitance of 1902.5F g(-1) at the current density of 1 A g(-1). A hybrid capacitor with NiCo2O4@CoS as the positive electrode and activated carbon as the negative electrode shows a high energy density of 32.91 Wh kg(-1) at the power density of 425 W kg(-1) and an excellent stability of 81.5% initial capacitance after 5000 cycles at 1 A g(-1). The conclusions indicate that the heterojunction of NiCo2O4@CoS can be a potential electrode for supercapacitors.

Automated summary

Constructing NiCo2O4@CoS composite electrode materials with heterojunctions on nickel foam enhances charge transfer and improves electrochemical performances for supercapacitors. The composite exhibits a synergistic effect and high electronic conductivity, leading to an outstanding capacitance of 1902.5F g(-1) and a high energy density of 32.91 Wh kg(-1) in a hybrid capacitor configuration.