Aqueous electrolyte polypyrrole | zinc cell with supercapattery performance

Abstract

Electrochemical oxidative polymerization at constant current density was used to produce polypyrrole (PPY) at graphite electrode from aqueous acidic electrolyte containing 0,1 mol dm-3 pyrrole and 1,0 mol dm-3 HCl. PPY electrode was than used as cathode while zinc electrode served as anode in electrochemical cell with an aqueous electrolyte containing 2,0 mol dm-3 NH4Cl and 1,1 mol dm-3 ZnCl2. The relevant electrochemical parameters of this cell were evaluated from electrochemical experiments. It was observed that charge of Zn|PPY cell started at voltage between 0,5 and 0,7 V and proceeded up to 1,5 V. Charge/discharge of the cell was dependent on charge/discharge current density with open circuit voltage of the fully discharged cell around 1,3 V. The estimated values of specific energy were between 46 and 68 W h kg-1 while specific power values were between 125 and 380 W kg-1, which suggested that Zn|PPY cell had “supercapaterry” behavior.

Elektroda na bazi polipirola (PPY) dobijena je elektrohemijskom oksidativnom polimerizacijom na grafitnoj elektrodi u uslovima konstantne gustine struje. Kao elektrolit za sintezu, korišćen je vodeni rastvor 0,1 mol dm-3 pirola i 1,0 mol dm-3 HCl. Formirana je elektrohemijska ćelija u kojoj je elektroda na bazi PPY korišćena kao katoda dok je anoda bila elektroda od cinka, a elektrolit se sastojao od vodenog rastvora 2,0 mol dm-3 NH4Cl i 1,1 mol dm-3 ZnCl2. Procena relevantnih elektrohemijskih i električnih parametara ove ćelije bazirana je na elektrohemijskim eksperimentima. Utvrđeno je da je proces punjenja/pražnjenja zavisio od struje punjenja/pražnjenja, punejnje ćelije započinje na naponu između 0,5 i 0,7 V, a završava se na naponu od oko 1,3 V. Procenjene vrednosti energije bile su između 46 i 68 W h kg-1, dok se za specifičnu snagu dobijaju vrednosti između 125 i 380 W kg-1, što ukazuje na superkapabaterijska svojstva Zn|PPY ćelije.