Polypyrrole/polymer electrolyte composites prepared by in situ electropolymerization of pyrrole as cathode/electrolyte material for facile electron transfer at the solid interface

Polypyrrole (PPy)/ion-conducting polymer electrolyte (PE) composites are prepared by in situ electropolymerization of pyrrole in a solvent-free PE matrix which is formed by photocross-linking of triacrylated poly(ethylene oxide-ca-propylene oxide) (TA). X-ray photoelectron spectroscopy measurements reveal the gradient structure at the PPy/PE interface where PPy is formed with the concentration gradient. For the composite film, a facile electron transfer across the PPy/PE interface is demonstrated by a cyclic voltammogram for the doping-undoping process? and a decrease in the charge-transfer resistance at the interface is proved by an electrochemical impedance analysis. This is in marked contrast to a combined bilayer film of PPy and TA-based PE for which an electron transfer across the interface between two polymer Films is not clearly observed. The composite exhibits charge-discharge performance, which suggests a possibility of fabricating solid-state batteries composed of conductive polymer electrode/ion-conductive PE/Li by one-step electrolysis. (C) 2001 The Electrochemical Society. All rights reserved.