Flower-like ZnO@MnCo2O4 nanosheet structures on nickel foam as novel electrode material for high-performance supercapacitors

Abstract

Hierarchical flower-like ZnO@MnCo₂O₄ nanosheets and dandelion-like MnCo₂O₄ were synthesized on nickel foam using a facile and cost-effective hydrothermal approach combined with a short post-annealing treatment. The surface properties, crystalline phase, and electrochemical properties of the flower-like and dandelion-like electrodes were studied by field emission scanning electron microscopy, X-ray diffraction, cyclic voltammetry, galvanostatic charge–discharge cycling, and electrochemical impedance spectroscopy. The flower-like ZnO@MnCo₂O₄ nanosheet electrode exhibited high specific capacitance of 631.2 F g⁻¹ and a high energy density of 56.10 W h kg⁻¹ at a current density of 1 A g⁻¹, which is higher than that of the dandelion-like MnCo₂O₄ electrode (452.5 F g⁻¹). Impressively, as an electrode material for supercapacitors, the flower-like ZnO@MnCo₂O₄ also shows exceptional cycling performance over 1000 charge/discharge cycles, indicating good long-term cycling stability. These results highlight the unique ZnO@MnCo₂O₄ electrode as a promising electrode for energy storage applications in supercapacitors.