LAUSR

Abstract Iron‑vanadium oxysulfide (Fe-VO-S) nanostructures with different Fe:VO atomic ratios are synthesized by a facile and low cost electrochemical deposition method. The synthesis of the various samples is confirmed by the physicochemical characterizations such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). For different Fe-VO-S nanostructures, the correlation between the physicochemical and the electrochemical properties is investigated. It is found that the Fe:VO atomic ratio has an important effect on the structure and size of the resulted particles. Also, the morphology of Fe-VO-S nanostructures has a remarkable influence on the electrochemical performance of the prepared samples. In addition, ternary Fe-VO-S nanostructures show better electrochemical performances compared to binary VO-S, in terms of high specific capacitance value and good cycling stability, because of the combined contributions from both of Fe and VO elements in the ternary nanostructures. Especially, the as-prepared Fe-VO-S nanostructure with Fe:VO molar ratio of 2:1 shows the highest specific capacitance value of 217 F g −1 at a current density of 3 A g −1 and also exhibits good cycling stability with 92% capacitance retention at a current density of 5 A g −1 after 4000 cycles. In addition, the Fe-VO-S nanostructure with the mentioned molar ratio of Fe:VO can be successfully applied to assemble a symmetric supercapacitor device and achieves good capacitive performances with a high specific capacitance (117 F g −1 at 3 A g −1 ), excellent energy density (9.3 Wh kg −1 at 2200 W kg −1 ) and power density (7200 W kg −1 at 1.2 Wh kg −1 ).