Effect of Cerium Oxide and rGO Conjugation on the Electrochemical Energy Storage Traits of V 2 O 5 Nanomaterials

Vanadium-based hybrid capacitors are highly promising and emerging candidates for energy storage and battery applications on a pilot scale owing to collective complementary advantages. In this study, vanadium pentoxide (V 2 O 5 ) and its composites with reduced graphene oxide (rGO) and cerium oxide (CeO 2 ) were successfully synthesized by employing the hydrothermal method. The structural, morphological, and optical characteristics were investigated by X-ray diffraction (XRD), scanning electron microscopy, and photoluminescence, respectively. The crystallite size calculated from the XRD pattern was found in the range of 17 nm to 20 nm approximately. X-ray photoelectron spectroscopy (XPS) analysis indicated the existence of variable oxidation states of Ce (+3 and +4) in the V 2 O 5 /CeO 2 composite materials. The V 2 O 5 /CeO 2 nanocomposite material showed excellent electrochemical response as compared to V 2 O 5 /rGO and bare V 2 O 5 . The V 2 O 5 /CeO 2 materials demonstrated a higher specific capacity ( Q s ) of 308 C/g as compared to V 2 O 5 /rGO (200 C/g) and V 2 O 5 (190 C/g) at the current density of 1 A/g. Theoretical investigations using Dunn’s model showed that the capacitive behavior of pristine V 2 O 5 was changed into a hybrid (capacitive and battery) and battery type when blended with rGO and CeO 2 , respectively. Graphical Abstract