Temperature-influenced synthesis of copper cobaltite electrodes for high-performance and sustainable asymmetric supercapacitor applications

Abstract

Transition metal oxides (TMOs) are widely regarded as potential electrode material for high-performance supercapacitors. In this study, CuCo₂O₄ was synthesised by a facile solvothermal route using ethanol as green solvent. A systematic study was conducted to assess the impact of solvothermal temperature on the morphological and electrochemical performance of CuCo₂O₄. The variation in solvothermal temperature resulted in the formation of distinct morphologies, such as microspheres at 120˚C, urchin-like structures at 150˚C, and flower-like architectures at 180˚C, as confirmed by FE-SEM and HR-TEM analyses. Among the synthesized samples, the material prepared at 150˚C (denoted as C-5) with urchin-like morphology exhibited the highest specific surface area of about 75.5 m²g^− 1. The electrochemical measurements also revealed that CuCo₂O₄(C-5) exhibits a maximum specific capacitance of 1133 F g^− 1 at a current density of 1 A g^− 1 and a capacitance retention of 82% after 8000 cycles in a three-electrode setup. The fabricated CuCo₂O₄(C-5)@NF // AC@NF-ASC device delivers a C_sp value of 156 F g^− 1 at 1 A g^− 1, retaining 80% initial capacitance over 8000 cycles. The device also exhibited a high energy density of 76 Wh kg^− 1 at a power density of 2040 W kg^− 1. In addition, the ASC device was powered a red LED, demonstrating its practical applicability for energy storage applications.