Self-assembly of two dimensional (2-D) Zn0.5Cu0.5Co2O4 quasi-nanosheets for asymmetric supercapacitor and oxygen evolution reaction applications

Abstract

Engineering the nanostructured ternary metal oxides with a high surface area is critical for multifunctional electrochemical applications. Herein, 2-D Zn0.5Cu0.5Co2O4 Quasi-nanosheets are prepared using the facile hydrothermal synthesis method and utilized for asymmetric supercapacitors and oxygen evolution reaction (OER) applications. As a supercapacitor electrode, the (2-D) Zn0.5Cu0.5Co2O4 quasi-nanosheets deliver a specific capacity of 669C g−1 at 1 A g−1 with a good rate capability of 339C g−1 at 30 A g−1 and withstand 96% of initial capacitance after 5000 cycles at 30 A g−1. In addition, the asymmetric supercapacitor Zn0.5Cu0.5Co2O4//AC (activated carbon) exhibits a high energy density of 55.1 W h kg−1 at a power density of 1280 W kg−1 and excellent cyclic stability of 94.9% capacity retention after 10000 charge/discharge cycles at 30 A g−1. In the OER process, the Zn0.5Cu0.5Co2O4 shows a low overpotential (160 mV at 20 mA cm−2), low Tafel slope (114.7 mV/dec), and high electrochemically active surface area. Moreover, the stability feature sustains for long-term use of 24 h. The post-physicochemical characterization techniques reveal the stability and mechanism of the supercapacitor electrode. The proposed approaches are significant for preparing various nanostructured ternary metal oxides for supercapacitors and water-splitting applications.