Engineering cationic vacancies on sphere-like zinc cobaltite microstructures via self-assembly of silkworm-like interconnected nanoparticles for battery-type supercapacitors

In this study, we utilized the solvothermal synthesis method to engender Zn vacancies on spinel ZnCo2O4 microspheres (V-Zn-ZCO), intending to improve their electrochemical performance. X-ray photoelectron spectroscopy was used to quantify the Zn vacancies, and this was supported by Rietveld refinement using X-ray diffraction data and energy-dispersive X-ray analysis. The resulting V-Zn-ZCO material had a high specific area of 53.60 m(2) g(-1) and an average pore diameter of 7.96 nm, which facilitated faster transport paths and greater surface area for rapid charge transfer. In terms of supercapacitor performance, the V-Zn-ZCO electrode exhibited battery-type behavior and achieved a high specific capacity of 367 C g(-1) at 1 A g(-1), as well as excellent rate capability with 82% of capacity retention. Furthermore, it displayed superior cycling stability with 76% retention of the maximum specific capacity after 5000 cycles. Therefore, our findings suggest that producing cationic vacancies is an effective strategy for improving the electrochemical performance of spinels.

Automated summary

In this study, Zn vacancies were generated on spinel ZnCo2O4 microspheres (V-Zn-ZCO) using the solvothermal synthesis method to enhance their electrochemical performance. The Zn vacancies were quantified using X-ray photoelectron spectroscopy, and the results were supported by Rietveld refinement and energy-dispersive X-ray analysis. The resulting V-Zn-ZCO material had a high specific area and an average pore diameter, enabling faster transport paths and greater surface area for rapid charge transfer. The V-Zn-ZCO electrode exhibited battery-type behavior, achieving a high specific capacity and excellent rate capability, as well as superior cycling stability. Therefore, this study demonstrates that producing cationic vacancies is an effective strategy for improving the electrochemical performance of spinels.