Electrochemical performances of CoFe2O4 nanoparticles and a rGO based asymmetric supercapacitor
CoFe2O4 nanoparticles were prepared using a polyethylene glycol (PEG) assisted solution combustion method. The X-ray diffraction pattern, Fourier transform infrared and Raman spectra revealed the single phase formation of CoFe2O4 particles. Transmission electron microscopy (TEM) images revealed nanosized particles less than 10 nm in size. The calculated voltammetry specific capacitance of the CoFe2O4 electrode was 195 F g−1 at 1 mV s−1. The Power's law suggests the capacitive mechanism is dominant over an intercalation mechanism, while the maximum number of charges accommodated in the inner surface of the electrode, is given by the Trasatti plot. The fabricated rGO based hybrid supercapacitor (CoFe2O4‖rGO) provides a good specific capacitance (38 F g−1) and energy density (12.14 W h kg−1) at 3 mA with good cycle life, and the serially connected asymmetric supercapacitor device powers the light emitting diode for 10 minutes.