Battery-type CuCo2O4/CoS nanograss arrays as a binder-free advanced electrode material for high-performance supercapacitors.

This study uses a facile one-step hydrothermal method to successfully synthesize hierarchical dandelion flower-like CuCo₂O₄/CoS structures on Ni foam. The composite exhibits a unique dandelion flower-like architecture comprising interconnected nanograss arrays (NGAs), resulting in a significantly higher surface area than individual CuCo₂O₄ and CoS electrodes. Electrochemical characterization reveals that the CuCo₂O₄/CoS electrode exhibits superior electrochemical performance, demonstrating battery-type behavior with well-defined redox peaks in cyclic voltammetry and distinct plateaus in galvanostatic charge-discharge curves. The composite electrode delivers a high specific capacity of 217.86 mA h g^-1 at a current density of 6 mA cm^-2, surpassing the performance of individual CuCo₂O₄ (142.54 mA h g^-1) and CoS (160.37 mA h g^-1) electrodes. Moreover, the composite electrodes exhibit outstanding cycling life, retaining 86.23% of their initial capacity in over 3000 cycles. Electrochemical impedance spectroscopy analysis confirms lower charge transfer resistance and solution resistance for the composite electrode, indicating improved charge transfer kinetics and ion diffusion. These findings demonstrate that the hierarchical CuCo₂O₄/CoS composite holds significant promise as a high-performance battery-type electrode material for supercapacitor applications.