Significance of Redox Additive Electrolyte over Energy and Power Densities of Mixed Metal Vanadate-Based Supercapattery Device
S. Arunpandiyan, G. Hariharan, A. Raja, R. Packiaraj, S. T. Bharathi, A. Arivarasan
Abstract
The energy demand of the current era suggests the need for the advancement of smart and efficient energy conversion/storage technologies. Thereby, a BiVO4/FeVO4:rGO nanocomposite-based supercapattery device was fabricated, and its electrochemical performances were reported. A BiVO4/FeVO4:rGO nanocomposite was synthesized through a hydrothermal route. The synthesized samples were characterized using XRD, FT-IR, Raman, UV, SEM, and HR-TEM analyses to study their structural, functional, optical, and morphological characteristics, respectively. In a three-electrode setup, the electrochemical properties of the produced samples were investigated using 1 M KOH and 0.1 M K4[Fe(CN)6] mixed with 1 M KOH redox additive electrolytes, respectively. With the redox additive electrolyte, a maximum specific capacitance of 1343.6 F g–1 was achieved for the BiVO4/FeVO4:rGO nanocomposite-modified working electrode. Further, the supercapattery device was fabricated by assembling a BiVO4/FeVO4:rGO-modified working electrode as the cathode and rGO deposited Ni foam as an anode in an asymmetrical cell configuration. The supercapattery device performance was also tested in pure and redox-additive-based KOH electrolytes, similar to the three-electrode system. The fabricated device exhibited a maximum energy density and power density of 29.7 W h kg–1 and 3780 W kg–1, respectively, in 1 M KOH electrolyte. The energy and power densities were improved to 70.5 W h kg–1 and 6300 W kg–1, respectively, by the inclusion of 0.1 M K4[Fe(CN)6] in 1 M KOH.