Improved electrochemical supercapacitive properties of CuO-Ni(OH)2 nanocomposites by eco-friendly low-temperature synthesis

Due to its impressive electrochemical supercapacitive behavior, low-temperature processed CuO-Ni(OH)2 nanocomposite-based electrode materials have gained much attention. In the present study, a facile, low temperature chemical precipitation technique was employed using polyvinylpyrrolidone (PVP) as a surfactant for the synthesis of CuO-Ni(OH)2 nanocomposite. To examine the structure and phase purity of the prepared nanocomposite, XRD is carried out. FT-IR analysis confirms the presence of functional groups related to the bare CuO, and Ni(OH)2, as well as the CuO-Ni(OH)2. The CuO-Ni(OH)2 nanocomposite formation and surface chemical properties is examined by FE-SEM, TEM and XPS analyses. The obtained UV result reveals a narrow band gap of ∼1.47 eV for CuO-Ni(OH)2. In this study, the developed electrodes show a specific capacitance of 151 F g-1 for CuO, 180 F g-1 for Ni(OH)2, and 436 F g-1 for the CuO-Ni(OH)2 electrode, which is two-fold greater than that of pristine sample. Additionally, the CuO-Ni(OH)2 electrode’s capacitive and diffusive charge contributions are investigated using Dunn’s method, which shows 90.52% of capacitive and 9.48% diffusive contributions at 20 mV s− 1. Charge-discharge profiles reveal a symmetrical and non-linear trend, confirming the electrodes' pseudo-capacitive behavior. Furthermore, after 3000 cycles, the CuO-Ni(OH)2 composite electrode reaches maximum efficiency of ∼89%. Results demonstrate that the developed CuO-Ni(OH)2 composite proves to be a promising alternative electrode for energy storage devices. Additionally, the synthesized CuO-Ni(OH)2 composite electrode demonstrates a better OER performance (overpotential: 0.396 V at 10 mA cm-2) compared to the reference catalysts. Due to its superior OER and supercapacitive properties, CuO-Ni(OH)2 based composite electrodes are envisaged to be used in next-generation electrochemical energy devices.