Synthesis and supercapacitor performance of Sm₃RuO₇ nanorods and Sm₃RuO₇/MnO₂ nanocomposite

In this work, we report the synthesis of Samarium ruthenate (Sm₃RuO₇) in the form of nanorods for the first time using the hydrothermal method, and Sm₃RuO₇-MnO₂ nanocomposite using the physical blending approach. To ascertain the materials´ phase formation, crystallinity, and average crystallite size, Powder X-ray diffraction (PXRD) analysis was used. The presences of vibrational modes in the samples were identified by Fourier transform infrared (FTIR) spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to identify the oxidation states and chemical elements that were present on the surface of the samples. The surface morphology of the samples was tested using Field emission scanning electron microscopy (FESEM). Along with XRD analyses, the crystalline nature of the samples and d-spacing were further confirmed using Transmission Electron Microscopy (TEM) images with selected area electron diffraction (SAED). The electrochemical behaviour of the samples was examined using cyclic voltammetry and chronopotentiometry techniques. The maximum specific capacitance of Sm₃RuO₇/MnO₂ was determined by cyclic voltammetry to be 805 F/g at a scan rate of 5 mV/s, which is higher than the 326 F/g of pure Sm₃RuO₇ at the same scan rate. At a current density of 1 A/g, the charge–discharge analysis of Sm₃RuO₇/MnO₂ produced a high specific capacitance of 802 F/g. The fast charge transfer kinetics of the materials was noticeable in the electrochemical impedance spectra. The incorporation MnO₂ in Sm₃RuO₇ provided extra interfacial sites, which led to the superior supercapacitive behaviour of the composite Sm₃RuO₇/MnO₂.