Facile synthesis of a MnFe2O4/rGO nanocomposite for an ultra-stable symmetric supercapacitor
In this paper, a binary MnFe2O4/reduced graphene oxide (MnFe2O4/rGO) nanocomposite is successfully synthesized using a facile approach. To possess larger layer spacing, worm-like expanded graphite (EG) is used instead of graphite for the synthesis of pristine graphene oxide (GO) suspension using the modified Hummer's method. Furthermore, the obtained GO suspension concentrated by Mn2+ ions is utilized to synthesize the MnFe2O4/rGO nanocomposite by precipitation of Mn2+ ions and in situ reduction of GO, simultaneously. The formation of the MnFe2O4/rGO nanocomposite and its individual constituents is confirmed using XRD, FT-IR, Raman, FE-SEM, TEM, BET, and TGA. Moreover, the magnetic properties of the samples are studied using a vibrating sample magnetometer. A hybrid supercapacitor is fabricated using a two-electrode system with a synthesized nanocomposite that demonstrates the specific capacitance of 271 F g−1 at the current density of 0.5 A g−1 in 6 M aqueous KOH electrolyte. It is worth noting that the cycling durability of the symmetric supercapacitor is excellent, in which 104% of primary capacitance is preserved after about 5000 periods. Thus, the obtained extraordinary electrochemical proficiency of the binary composite is a result of the specific construction and the qualified electrical conductivity of the rGO nanosheets.