Three dimensional vanadium pentoxide/graphene foam composite as positive electrode for high performance asymmetric electrochemical supercapacitor

• Published in: Journal of colloid and interface science 2018-12, Vol.532, p.395-406
• Main Authors: Ndiaye, Ndeye M., Ngom, Balla D., Sylla, Ndeye F., Masikhwa, Tshifhiwa M., Madito, Moshawe J., Momodu, Damilola, Ntsoane, Tshepo, Manyala, Ncholu
• Format: Article
• Language: English
• Subjects: 3D V2O5; Asymmetric supercapacitors; C-Fe/PANI; Composite; Graphene foam
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2018.08.010

Schematic illustration of the synthesized V2O5/GF-150 mg composite and Ragone plot of asymmetric cell. [Display omitted] The electrochemical performance of hydrothermal synthesized three dimensional (3D) orthorhombic vanadium pentoxide (V2O5) nanosheets and vanadium pentoxide/graphene foam (V2O5/GF) composites at different mass loading of GF were successfully studied. The optimized V2O5/GF-150 mg composite provided a high specific capacity of 73 mA h g−1, which was much higher than that the pristine V2O5 (60 mA h g−1) nanosheets at a specific current of 1 A g−1. A hybrid capacitor was also fabricated by adopting a carbon-based negative electrode obtained from the pyrolysis of an iron-PANI polymer (C-Fe/PANI) mixture and the 3D V2O5/GF-150 mg composite as the positive electrode in 6 M KOH electrolyte. The hybrid device of V2O5/GF-150 mg//C-Fe/PANI demonstrated a high energy density of 39 W h kg−1 with a corresponding high power density of 947 W kg−1 at a specific current of 1 A g−1 in an operating voltage window of 0.0–1.6 V. The hybrid device also exhibited an excellent cycling stability with 74% capacity retention recorded for up to 10,000 constant charging–discharge cycles and an excellent ageing test at a specific current of 10 A g−1.