The preparation of MnFe2O4 decorated flexible graphene wrapped with PANI and its electrochemical performances for hybrid supercapacitors

Abstract

A modest, cost effective and eco-friendly method is employed for the preparation of MnFe₂O₄ nanocube decorated, flexible graphene sheets, followed by polyaniline (PANI) which is wrapped by an in situ chemical oxidative polymerization method. The formation of the hybrid composites and their individual constituents are realized through X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR) and Raman spectroscopy. The MnFe₂O₄ nanocube decorated flexible graphene and PANI wrapped composite is visualised through transmission electron microscopic (TEM) images. The decorated MnFe₂O₄ particles have sizes in the range of 75–100 nm. The capacitive properties of the ternary composite is investigated and it has the obtained specific capacitance of 338 F g⁻¹ at 0.5 mA cm⁻² in 1 M NaCl aqueous electrolyte, which is 10 times greater than the pristine MnFe₂O₄ (32 F g⁻¹). Similarly, the fabricated hybrid supercapacitor (MGP‖AC) provides the specific capacitance of about 51.87 F g⁻¹ at 5 mV s⁻¹ and its energy density is 10.25 W h kg⁻¹ at 10 mA cm⁻². Thus the obtained significant properties of the ternary composite are due to the distinctive characteristics of the individual constituents which leads to enhanced electrochemical properties like reducing the internal resistance and diffusion path length via the synergistic effect.