We have fabricated a symmetric electrochemical capacitor with high energy and power densities based on a composite of graphene foam (GF) with 80 wt% of manganese oxide (MnO(sub2)) deposited by hydrothermal synthesis. Raman spectroscopy and X-ray diffractionmeasurements showed the presence of nanocrystallineMnO(sub2) on the GF, while scanning and transmission electron microscopies showed needle-like manganese oxide coated and anchored onto the surface of graphene. Electrochemical measurements of the composite electrode gave a specific capacitance of 240 Fg(sup-1) at a current density of 0.1 Ag(sup-1) for symmetric supercapacitors using a two-electrode configuration. A maximum energy density of 8.3 Whkg(sup-1) was obtained, with power density of 20 kWkg(sup-1) and no capacitance loss after 1000 cycles. GF is an excellent support for pseudo-capacitive oxide materials such as MnO(sub2), and the composite electrode provided a high energy density due to a combination of double-layer and redox capacitance mechanisms.
Reference:
Bello, A, Fashedemi, O.O, Lekitima, J.N, Fabiane, M, Dodoo-Arhin, D, Ozoemena, K.I, Gogotsi, Y, Johnson, A.T.C and Manyala, N. 2013. High-performance symmetric electrochemical capacitor based on graphene foam and nanostructured manganese oxide. AIP Advances, vol. 3, pp 1-10
Bello, A., Fashedemi, O., Lekitima, J., Fabiane, M., Dodoo-Arhin, D., Ozoemena, K., ... Manyala, N. (2013). High-performance symmetric electrochemical capacitor based on graphene foam and nanostructured manganese oxide. http://hdl.handle.net/10204/7510
Bello, A, OO Fashedemi, JN Lekitima, M Fabiane, D Dodoo-Arhin, KI Ozoemena, Y Gogotsi, ATC Johnson, and N Manyala "High-performance symmetric electrochemical capacitor based on graphene foam and nanostructured manganese oxide." (2013) http://hdl.handle.net/10204/7510
Bello A, Fashedemi O, Lekitima J, Fabiane M, Dodoo-Arhin D, Ozoemena K, et al. High-performance symmetric electrochemical capacitor based on graphene foam and nanostructured manganese oxide. 2013; http://hdl.handle.net/10204/7510.
Copyright: 2013 American Institute of Physics (AIP): AIP Advances. This is an Open Access journal. The journal authorizes the publication of the information herewith contained. Published in AIP Advances, vol. 3, pp 1-10
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