In situ synthesis of advantageously united copper stannate nanoparticles for a new high powered supercapacitor electrode

Abstract

In this study, we demonstrate the design and fabrication of a novel flexible nanoarchitecture by facile coating ultrathin copper stannate nanoparticles (Cu₂SnO₄ NPs) grown radially on nickel foam (NF) to achieve a high specific capacitance, high-energy density, high-power density, and long-term life for supercapacitor electrode applications. The structural and morphological properties of the material were characterized using different techniques. The Cu₂SnO₄ NPs were used as the active electrode material for supercapacitor applications. The electrochemical properties of the Cu₂SnO₄ NPs as a binder-free electrode for a supercapacitor were examined using cyclic voltammetry (CV), galvanostatic charge and discharge analysis (GCD), electrochemical impedance spectroscopy (EIS), and cycle life measurements in 2 M KOH electrolyte. The GCD analysis exhibited a specific capacitance as high as 2329.68 F g⁻¹ at 1 A g⁻¹ and a good rate capability (1330 F g⁻¹ at 70 A g⁻¹). Moreover, this approach also offers an exceptionally high area-normalized capacitance of 4.66 F cm⁻². This capacitor electrode has excellent cyclic stability with 91.4% capacitance retention after 3000 cycles at 20 A g⁻¹, together with 99.2% Coulomb efficiency in a three-electrode system. The superior electrochemical performance of the Cu₂SnO₄ NPs/NF composites is attributed to the synergistic effects of the hierarchical porosity, Cu₂SnO₄ NPs, and 3D nickel foam network structure, which can effectively accommodate the huge volume change of the Cu₂SnO₄ nanoparticles during cycling and maintain perfect electrical conductivity throughout the electrode. Furthermore, the asymmetric supercapacitors (ASCs) based on the as-obtained Cu₂SnO₄ NPs cathode and activated carbon (AC) anode displayed an excellent electrochemical behavior with a high energy density of 91.04 W h kg⁻¹ at 4.35 kW kg⁻¹ and superior cyclic stability. It also shows a small leakage current. Furthermore, the SC device retains 1.1 V of its initial voltage (1.4 V) after the 8 h self-discharge test, which suggests the good state of health of the SC device. These results demonstrate that Cu₂SnO₄ NPs could be a promising electrode for high-performance energy storage devices.