Ionic conduction and phase separation studies in PEO-P(VdF-HFP)-LiClO₄-dedoped polyaniline nanofiber composite polymer electrolytes — I

摘要

In the present work, dispersion of dedoped polyaniline nanofibers into PEO-LiClO₄ blended with P(VdF-HFP) has been discussed. Polyaniline nanofibres have been synthesized by a gentle interfacial polymerization route. The nanofibers are dedoped with base NaOH and films of PEO-P(VdF-HFP)-LiClO₄-dedoped polyaniline nanofibres are prepared by solution casting method with varying concentration of dedoped (insulating) nanofibers (from 5 wt. % to 25 wt. %). The synthesized polymer electrolyte films have been characterized by ac impedance analysis, XRD and SEM. The ionic conductivity of PEO-P(VdF-HFP)-LiClO₄ electrolyte system increases with increase in concentration of dedoped polyaniline nanofibers. The high aspect ratio (> 50) nanofibres prevent PEO-P(VdF-HFP)-LiClO₄ electrolyte matrix from reorganization resulting in increase in amorphicity that leads to enhancement in ionic conductivity. However, the XRD results show that at higher concentration (> 15 wt. %) the nanofibres get phase separated out from the polymer electrolyte phase and start forming insulating clusters which impedes the ion motion. SEM studies confirm the formation of domain like structure of nanofibres at higher concentration, which act as physical barrier for the conduction of Li+ ions.