In Situ Synthesis of a Polyaniline/ Fe-Ni Codoped CoO Composite for the Electrode Material of Supercapacitors with Improved Cyclic Stability.

Conductive polymers have become a remarkable candidate for electrode materials of supercapacitors. Polyaniline (PANI) is the most promising contender for supercapacitors because of its easy method of synthesis, low cost, and higher choice in the improvement of energy storage applications. The main issue in the use of PANI in supercapacitors is its lower stability. In this work, PANI@Fe-Ni codoped CoO (PANI@FNCO) nanocomposite has been prepared by in situ addition of 10 wt % FNCO as fillers in the PANI matrix. The nanocomposites were then characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry to observe the morphology, crystal structure, functional groups, and thermal stability of samples, respectively. SEM results showed that FNCO was fairly dispersed in the PANI matrix, while XRD results showed a broad peak for nanocomposites because of the semicrystalline nature of polymers. The electrochemical properties of the samples were analyzed via cyclic voltammetry, galvanostatic charge and discharge, and electrochemical impedance spectroscopy. PANI@FNCO nanowires are found to overcome the shortcomings in electrochemical energy storage devices by exhibiting a higher value of specific capacitance of 1171 F g and energy density of 144 W h kg at a current density of 1 A g. Moreover, the FNCO nanowires also showed a cyclic charge/discharge stability of 84% for 2000 cycles.