The Study of Supercapacitive Stability of MnO2/MWCNT Nanocomposite Electrodes by Fast Fourier Transformation Continues Cyclic Voltammetry

In this work, the nanostructured MnO2 was uniformly coated on the multi-walled carbon nanotube (MWCNT) by a sonochemical method, and the effect of MWCNT amount on the supercapacitive performance of the nanocomposites were investigated. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), transition electron microscopy (TEM) and scanning electron microscopy (SEM). Also, the specific capacitances (SCs) of the MWCNT/MnO2 electrodes were studied by cyclic voltammetry (CV). The result shows that the loading the nanocomposite with of MnO2 was 65 wt. %, the electrode has a high SC of 394 F g(-1) (at scan rate of 2 mV s(-1) in a 0.5 M Na2SO4) indicating a better performance than that of pristine MnO2 electrodes (289 F g(-1) at scan rate of 2 mV s(-1)). Fast Fourier transformation continuous cyclic voltammetry (FFTCCV) technique was used to study stability and separation of charge and discharge curves of the nanocomposite electrodes, over a large number of cycles (at scan rates 200 mV s(-1)). The results indicated SC that the capacitance of the composite electrode decreases only 3.2% of initial capacitance, after 4000 cycles. Therefore, the prepared composite could be potential electrode materials for supercapacitors.