Charge-discharge characteristics of polythiophene as a cathode active material in a rechargeable battery

Abstract

Polythiophene films were electrochemically deposited on glassy carbon substrates under potentiostatic control and used as cathode active material together with a Zn anode in a rechargeable battery with propylene carbonate, Zn(ClO4)2, LiClO4 electrolyte. Charge-discharge characteristics were studied. The average discharge voltage of the polythiophene/Zn cell was 1.25 V. In the low current density region (i.e. 10-50 μA cm-2) the cycling coulombic efficiency was above 95%, but in the fast charge-discharge region, where current densities were 0.1-0.5 mA cm-2, the coulombic efficiency decreased to 55% with increasing discharge rate. Additionally, it was found that the cyclic coulombic efficiency was a function of the charging depth.