Enhanced battery-type supercapacitor performance based on composite structure of nickel cobaltite and cadmium sulfide

In this study, a composite structure based on NiCo2O4/CdS was synthesized on nickel foam using hydrothermal and chemical bath deposition (CBD) methods. An ultrathin nanosheet of NiCo2O4 was coated by CdS nanocrystals by varying the CBD reaction time. Synergistic effects arising from the NiCo2O4 nanosheets and CdS nanocrystals were studied for prospective electrochemical energy storage applications. The NiCo2O4/CdS composite electrode with optimized CBD reaction time of CdS coating exhibited a high specific capacity of 331 mAh g−1 at 30 mA, which is higher than pristine NiCo2O4 (260 mAh g−1). In addition, for practical applications, we fabricated an asymmetric cell based on the NiCo2O4/CdS as positive electrode and activated carbon as negative electrode and its electrochemical performance was studied in detail. This work provides a foundation for different metal-oxide- and metal-sulfide-based composite electrodes for energy storage studies. Synthesis and fabrication of NiCo2O4 and NiCo2O4/CdS electrode by all chemical synthesis route. [Display omitted] •NiCo2O4 electrode is synthesized by hydrothermal technique.•NiCo2O4/CdS composite is synthesized using chemical route.•NiCo2O4/CdS exhibited high specific capacity of 331 mAhg−1.•An excellent cycling stability with a capacity retention of 93.3% is observed.•Efficient energy storage device fabrication by simple and cost-effective chemical approach.