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-co-propylene oxide) (TA). X-ray photoelectron spectroscopy measuremenls 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 interlace 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.