A honeycomb-like ZnO/SnO2 nanocomposite on nickel foam for high-performance asymmetric supercapacitors

Abstract

In this work, a honeycomb-like ZnO/SnO₂ nanocomposite was synthesized on nickel foam (NF) using a single-step hydrothermal route for achieving good electrochemical performance. The as-prepared electrode showed an excellent electrochemical performance in 3 M KOH electrolyte, a superior specific capacitance (C_s) of 2307 F g⁻¹ and good stability, 78.8% retention of its initial value after 7000 galvanic charge–discharge (GCD) cycles in a three electrode system. An asymmetric supercapacitor (ASC, ZnO/SnO₂@NF//AC@NF) exhibited a maximum C_s of 133 F g⁻¹ with 92.8% retention after 4000 GCD cycles. The calculated energy and power density were 47.28 W h kg⁻¹ and 10.4 kW kg⁻¹ respectively. Our investigations demonstrate that the as-synthesized ZnO/SnO₂ nanocomposite could be a good competitor as an electrode material in high-performance electrochemical energy storage applications.