Electrochemical Syntheses Of Polypyrrole And Its Application In Supercapacitor

Polypyrrole (PPy) was synthesized through electropoymerization of pyrrole using Cl- as the dopant in aqueous medium. The capacitive properties of the PPy in 0.5 mol·L-1 H2SO4 or 1 mol·L-1 KCl (pH=6.0) were studied through cyclic voltammetry (CV) and constant current charging-discharging experiments. The PPy was also studied by FT-IR spectroscopy. Symmetric supercapacitor was constructed by using the PPy as the electrode material and 1 mol·L-1 KCl (pH=6.0) as the electrolyte.The PPy displayed better capacitive behaviors in 0.5 mol·L-1 H2SO4 during-0.4～0.6 V (vs. SCE) than in 1 mol·L-1 KCl (pH=6.0) during-0.2～0.6 V (vs. SCE), due to easier doping-dedoping of Cl- into-out of the polymer than that of HSO4-. The specific capacitance of the PPy in 1 mol·L-1 KCl (pH=6.0) increased as the acidity of the electropolymerization media increased up to [H+]=1.0 mol·L-1. The PPy made in the solution of [H+]=1.0 mol·L-1 displayed a specific capacitance of 544.6 F·g-1 when charging-discharging at 1 mA·cm-2. Characteristic vibrations of PPy and doped Cl- appeared at 3443,1623,1430 cm-1 and 625cm-1 on the FT-IR spectrum of PPy. Symmetric supercapacitor constructed by using the PPy as electrode material and 1 mol·L-1 KCl (pH=6.0) as the electrolyte displayed a specific capacitance of 136.4 F·g-1 when charging-discharging at 3 mA·cm-2.