Supercapacitive studies on electropolymerized natural organic phosphate doped polypyrrole thin films
We report the electropolymerization of phytic acid (PA) doped polypyrrole (PPy) thin film for supercapacitor application. The surface morphology and presence of various functional groups in PA doped PPy films were analyzed using scanning electron microscopy, FTIR and Raman spectroscopy. The electrochemical properties and supercapacitor behavior of the PA/PPy thin films were performed using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge techniques in 1 M H2SO4 electrolyte. The effect of various experimental conditions such as concentration of pyrrole monomer, phytic acid and deposition time have been studied to affirm the optimized electropolymerization of PA doped PPy thin film. Among these, 0.1 M PA doped 0.6 M of pyrrole thin film deposited on stainless steel (SS) substrate for 10 min exhibited a maximum specific capacitance of 297 Fg¿1 and energy density 41.25 Whkg¿1 at 5 mVs¿1 scan rate. In addition, the same optimum condition have been extended for electropolymerization of PA/PPy thin film on titanium (Ti) substrate and achieved a maximum specific capacitance of 343 Fg¿1 with high energy density 47.64 Whkg¿1 at 5 mVs¿1 scan rate. Moreover, SS and Ti substrate coated PA/PPy electrodes show high charge/discharge efficiency at 10 Ag¿1 current density with ¿91% and 77% of specific capacitance retention after 4000 cycles, which indicates good electrochemical reversibility and cycling stability of the fabricated electrodes.