Hierarchical maple leaf-like spinel oxide microarchitectures via a novel eco-friendly approach as a cathode material for aqueous hybrid supercapacitors

The development of three-dimensional (3D) microarchitectures with desirable porous surface morphologies has gained extensive attention in the area of energy storage system due to their superior structural characteristics. The porous morphology consists of high surface area which could be useful for the demonstration of superior energy storage ability to their solid counterpart on account of the easy access of electrolyte ions into the active material. Herein, we designed the 3D flower-like CuCo₂O₄ and 3D maple leaf-like CuCo₂O₄ microarchitectures using a facile and nature-friendly oil-bath (silicone oil) process and subsequent calcination in the ambient atmosphere. The prepared CuCo₂O₄ products revealed 3D flower-like and maple leaf-like microarchitecture morphologies by the exchange of the solvents during synthesis. The synthesized porous materials-based electrodes showed dominant battery-like electrochemical performance in aqueous alkaline media. Interestingly, the 3D maple leaf-like CuCo₂O₄ microarchitectures exhibited a prominent surface area of 153.33 m² g⁻¹ which can empower additional electroactive sites to access more electrolyte ions diffused into the electrode and showed a good specific capacity ~302 mA h g⁻¹ at 1 A g⁻¹ with excellent cycling and rate capability. These superior results are achieved due to the unique 3D maple leaf-like morphological shape and its high porous feature from its surface. Moreover, a pouch-type hybrid supercapacitor was constructed and it showed better energy and power density values of 38.54 Wh kg⁻¹ and 7250 W kg⁻¹, respectively. Finally, the fabricated device was tested for practical usage while operating low-power electronics.