Optimizing the preparation conditions of polypyrrole electrodes for enhanced electrochemical capacitive performances

Abstract

Here, we put forward an optimum proposal to prepare high-performance polypyrrole (PPy) electrodes for supercapacitor applications. A detailed study regarding the effects of different preparation conditions including electropolymerized mode, parameter, and current collector on the electrochemical capacitive performances of PPy electrodes is carried out. Fourier transform infrared spectroscopy and X-ray diffraction tests indicate the above preparation conditions have no effect on the component and crystal structure of PPy prepared. Electrochemical measurements manifest a significant effect of current collector on supercapacitive properties of PPy electrodes. Graphite foil as the current collector with low resistance shows remarkably superior capacitive performances compared with FTO-conducting glass and ITO conductive plastic. SEM characterizations show galvanostatically polymerized PPy particles have obviously smaller aggregation degree than potentiostatically polymerized PPy particles, which results in better electrochemical properties for former. Among different preparation conditions, the PPy deposited on graphite foil under galvanostatic mode with 2 mA cm−2 shows the best electrochemical capacitive properties. The optimized PPy/graphite electrodes show a high specific capacitance of 173.0 mF cm−2 at 0.2 mA cm−2, superior rate capability, and outstanding cycling stability (retaining 90.5% of initial capacitance for 5000 cycles).