Fe-doped NaV3O8 thin films as an efficient electrode with enhanced performance for asymmetric supercapacitor device

Abstract

Pure and Fe-doped NaV3O8 films on SS substrates were prepared using the cost-effective spray pyrolysis technique. Fe has been doped into the NaV3O8 at different weight percentages of 1, 3 and 5. Preliminary characterizations like XRD and SEM analysis have been carried out for the deposited films to study the changes that occur in the structural and morphological properties of the films caused by doping. The EDAX analysis determines the elements present in the film, whereas the oxidation states of the elements present were determined by XPS analysis. The surface wettability test reveals the hydrophilic nature of the films. A three-electrode system with 1 M NaNO3 aqueous electrolyte was used to study the electrochemical characteristics of the prepared films. The results have shown that the 3 wt% Fe-doped NaV3O8 film achieved a specific capacitance of 131 F/g at a current density of 0.5 A/g surpassing the performance of pure NaV3O8 film. Subsequently, a 3 wt% Fe-doped NaV3O8 // AC configured asymmetric supercapacitor device was fabricated and it displayed a specific capacitance of 13.4 F/g with a specific energy and power density of 1.86 Wh/kg and 999 W/kg, respectively at a current density of 0.5 A/g. The device obtained a capacitance retention of 70.1 % even after 5000 cycles. Therefore, the present study probes into the impact of incorporating Fe into NaV3O8, by exploring its structural, morphological, and electrochemical characteristics.