Efficient energy storage performance of in situ grown Co₃V₂O₈-RGO composite nanostructure for high performance asymmetric Co₃V₂O₈-RGO//RGO supercapacitors and consequence of magnetic field induced enhanced capacity

In this work, cobalt vanadate/reduced graphene oxide (Co₃V₂O₈/RGO) composite nanostructure has been synthesized via in-situ reduction of graphene oxide (GO) in the presence of cobalt chloride and sodium metavanadate through hydrothermal following post calcinations treatment. Characterizations through various techniques have been performed to probe the physicochemical properties of Co₃V₂O₈/RGO, RGO and Co₃V₂O₈ nanostructures. Our Results show that because of the synergistic effect, Co₃V₂O₈/RGO composite nanostructure exhibits superior electrochemical properties as compared to bare RGO and Co₃V₂O₈. At a current density of 0.5 A/g the specific capacity has been recorded to be 118.82, ∼179, and ∼241.67 Cg^-1 in case of Co₃V₂O₈, RGO and Co₃V₂O₈/RGO nanostructures, respectively. Moreover, Co₃V₂O₈/RGO composite nanostructure (positive electrode) and RGO (negative electrode) have been employed to prepare the asymmetric supercapacitor, exhibited high specific capacity (127.62Cg^-1), energy density (28.36 Whkg⁻¹), and power density (400 Wkg^-1) at a current density 0.5 A/g. This asymmetric supercapacitor shows excellent capacity retention (∼91.64%) and columbic efficiency (∼98.61%) measured at a current density of 5 A/g after 10,000 charge/discharge cycles. More importantly, a dramatic increase ∼170% (344 Cg^-1) and ∼67% (185 Cg^-1) in the specific capacity have been recorded at a current density of 0.5 A/g and 1.0 A/g, respectively when asymmetric supercapacitor device is subjected to an external magnetic field of strength of 0.5 T. Additionally, under the applied magnetic field, capacity retention ∼97.75% and columbic efficiency ∼98.84% has been recorded at a current density of 5 A/g after 10,000 cycles.