Hybrid SnO2–Co3O4 nanocubes prepared via a CoSn(OH)6 intermediate through a sonochemical route for energy storage applications

Abstract

A cubic-like nanostructured SnO₂–Co₃O₄ hybrid was sonochemically synthesized via formation of CoSn(OH)₆ nanocubes as an intermediate at room temperature in the presence of stannous and cobalt precursors, without the assistance of any surfactant or template. The obtained hybrid maintained the original frame structure of CoSn(OH)₆ nanocubes. The above samples were characterized by thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The electrochemical performance of the hybrid SnO₂–Co₃O₄ nanocubes was investigated as a supercapacitor electrode material through cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) studies. The cubic-like nanostructured hybrid SnO₂–Co₃O₄ exhibits enhanced supercapacitor performance. The hybrid SnO₂–Co₃O₄ nanocubes delivered a maximum specific capacitance of 484 F g⁻¹, which was more than four-fold higher than bare SnO₂ (101 F g⁻¹) and intermediate CoSn(OH)₆ nanocubes at the same current density of 0.5 mA cm⁻² in the potential range between 0 and +1 V. The enhancement of the overall electrochemical behaviour of the electrode material can be attributed to the synergetic effect between nanostructured SnO₂ and Co₃O₄. About 77% of its initial capacitance was retained after 1000 cycles, which demonstrates its high electrochemical stability and capacitance retention. The obtained results confirmed that this material is a promising candidate for supercapacitor applications.