Synthesis, structural and electrochemical investigations of reduced graphene oxide loaded zinc vanadate nanoparticles for high performance supercapacitors

In this study, supercapacitor performances of reduced graphene oxide-loaded zinc vanadate (Zn3(VO4)2 - ZV) nanoparticles (NPs) were reported. Reduced graphene oxide (rGO) loaded zinc vanadate (Zn3(VO4)2@rGO - ZVR) nanocomposites (NCs) were synthesized through a simple reflux method and their structural, functional group, and morphological properties were analyzed by X-ray diffraction, FT-IR, and electron microscopic analyses. Working electrodes of ZV NPs and ZVR NCs were fabricated using doctor blade technique and their supercapacitor performances were tested with an aqueous KOH electrolyte. Incorporation of rGO greatly enhanced the specific capacitance value of ZV NPs from 104 F g-1 to 1910 F g-1 at 5 mVs- 1 (CV studies). At the same, the highest specific capacitance value from the GCD analysis was found to be 1315 F g-1 for ZVR NCs, which was very much greater than pure ZV NPs (53.7 F g-1). The fabricated asymmetrical supercapacitors using ZVR NCsbased working electrode exhibited the higher power and energy densities of 2050 W kg-1 and 13.13 Wh kg-1, respectively. Furthermore, the fabricated supercapacitors demonstrated an excellent cyclic stability of 95.1 % after 2000 GCD cycles, when compared to ZV NPs (90 %). The electrochemical results proved that the supercapacitor performances of ZV NPs were greatly enhanced by the addition of rGO.