Advanced NiCo2O4 /ZnO-CuO/NF composite for high-performance asymmetric supercapacitor and efficient oxygen evolution reaction applications
Muhammad Ali Bhatti, Shusheel Kumar, Aneela Tahira, Adeel Liaquat Bhatti, Zaheer Ahmed Ujjan, Mansab Ali Jakhrani, Umair Aftab, Riyadh H. Alshammari, Ayman Nafady, Elmuez A. Dawi, Mélanie Emo, Brigitte Vigolo, Antonia Infantes‐Molina, Zafar Hussain Ibupoto
Abstract
Abstract It is imperative that composite systems with high performance, low-cost, enhanced simplicity, and scalability be developed in order to convert and store energy. This, however, has been a challenging endeavor throughout the years. In this study, we present a cost-effective, efficient, scale-up-friendly, and environmentally friendly method of producing in situ sandwich layers of ZnO-CuO composite between NiCo 2 O 4 nanostructures and nickel foam using lemon peel extract (LPE) during hydrothermal processes. NiCo 2 O 4 /ZnO-CuO/nickel foam was analyzed using powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). According to XRD and HRTEM studies of NiCo 2 O 4 /ZnO-CuO/nickel foam, NiCo 2 O 4 , ZnO, and CuO exhibit cubic, hexagonal, and monoclinic phases, respectively. With NiCo 2 O 4 /ZnO-CuO/nickel foam as the active anode electrode, an asymmetric supercapacitor has been developed in an alkaline solution of 3 M KOH. At a low current density of 2 Ag −1 , the asymmetric supercapacitor exhibited a high specific capacitance of 3614.8 F g −1 , a power density of 1549.2 W kg −1 , and an energy density of 75.3 Wh kg −1 . Upon repeatable 40,000 galvanic charge–discharge cycles, the asymmetric device demonstrated a high specific capacitance retention percentage of approximately 100 to 95 and a columbic efficiency of 98%. Moreover, NiCo 2 O 4 /ZnO-CuO/nickel foam composite had a low overpotential of 210 mV at 40 mA cm −2 and a Tafel slope of 70 mV dec −1 for OER in 1 M KOH. During continuous OER measurements over a period of 40 h, NiCo 2 O 4 /ZnO-CuO/nickel foam composites demonstrated high durability and stability. NiCo 2 O 4 /ZnO-CuO/nickel foam exhibits good electrochemical performance as a result of its synergetic effects, its high conductivity, its abundant exposed catalytic sites, its oxygen vacancies, and its high durability. Graphical Abstract The illustration for the synthesis of high-performance in situ NiCo 2 O 4 /ZnO-CuO/nickel foam composite for OER and supercapacitor application.