The first-principles study of CoSb2O4 and its electrochemical properties for supercapacitors. (1st September 2018)

• Record Type: Journal Article
• Authors: Shanmugavani, Amirthalingam; Lalitha, Murugan; Narayanan Kutty, Rajeesh Kumar; Vasylechko, Leonid; Lee, Yun Sung; Lakshmipathi, Senthilkumar; Kalai Selvan, Ramakrishnan
• Is Part Of: Electrochimica acta. Volume 283(2018)
• Page Start: 949
• Page End: 958
• Publication Date: 2018-09-01
• Subjects: First principle study -- Cobalt antimonite -- Hydrothermal synthesis -- A hybrid capacitor; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2018.06.193
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: By varying Co:Sb molar ratio, crystalline CoSb2 O4 was synthesized through surfactant free hydrothermal method. The tetragonal crystal structure and phase composition of cobalt antimonate were obtained through XRD Rietveld refinement method. CoSb2 O4 exhibits a direct band gap of 2.89 eV was computed using First-principle density functional theory (DFT) calculations. Here, the Fermi energy level is upshifted to conduction band region, representing the n-type behaviour of the CoSb2 O4 unit cell. The oxidation state of +2 and + 3 of Co was identified through X-ray photoelectron spectroscopy analysis (XPS). Formation of submicron size, rod shape particles was confirmed by Transmission electron microscopic (TEM) images. Cyclic voltammogram exhibits a specific capacitance of 598 F g −1 at 2 mV s −1 in 1 M KOH. More importantly, Galvanostatic charge-discharge analysis (GCD) delivered the specific capacitance of 382 F g −1 at 1 mA cm −2 . For practical application, an asymmetric supercapacitor is constructed using Ni3 (Fe(CN)6 )2 (H2 O) as a positive electrode and synthesized one-dimensional CoSb2 O4 as a negative electrode, which offered a maximum specific capacitance of 279 Fg -1 at 1 mV s −1 . Cycling stability of the fabricated device demonstrated the retention of almost 100% and hence depicts its promising nature as an efficient electrode for supercapacitor application.