Abstract
We report hydrothermal synthesis of Lanthanum tungstate (La-2(WO4)(3)) as an electrode materials for supercapacitor applications. The electrochemical properties of the nanoparticles were investigated using cyclic voltammetry galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy in 2.0 M KOH solution as an aqueous electrolyte. The highest specific capacitance of 920.1 F/g was achieved at a scan rate of 5.0 mV/s. A discharging time of 370.43 s was also recorded. La-2(WO4)(3) shows excellent electrochemical performance with power density of 1876.9 Wkg(-1) and energy density of 19.5 Whkg(1). La-2(WO4)(3) is employed as a positive and graphite as a negative electrode in a two-electrode system. The outstanding energy density of 77.7 Wh/kg and power density of 562.7 W/kg was achieved at a current density of 1.0 A/g while a high power density of 4028.8 W/kg is attained with energy density of 39.79 Wh/kg at a current density of 7.0 A/g. The device shows the outstanding capacity retention of 83.8% after 2000 GCD cycles. Additionally, the charge storage mechanism is analyzed for the asymmetric supercapacitor using Dunn's model. The capacitive and diffusive behavior of whole nanomaterials was examined in detail; also the exponent law is utilized to ascertain the asymmetric nature of the fabricated material, determined through b values. This favorable behavior of La-2(WO4)(3) suggest potential candidature for electrode in asymmetric supercapacitor application.