Hot-press synthesized polyethylene oxide based proton conducting nanocomposite polymer electrolyte dispersed with SiO 2 nanoparticles

Abstract

Ion transport studies on polyethylene oxide (PEO) based nanocomposite polymer electrolyte (NCPE) membranes (PEO: NH 4HSO 4) dispersed with nanosized SiO 2 particle in varying wt.(%) have been reported. NCPE films have been cast by a novel hot-press (extrusion) technique. Scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infra-red (FTIR) spectroscopy, ionic transport number ( t ion) and electrical conductivity ( σ) studies have been carried out on hot-press films and the results have been compared with NCPE films prepared by the standard solution cast technique. As a consequence of dispersion of a fractional amount of nanosized SiO 2 filler particles into the polymer-salt complex (PEO: NH 4HSO 4) host matrix, an enhancement of approximately an order of magnitude in the room temperature conductivity resulted. NCPE membranes with SiO 2 content: 5 wt.% (Solution cast) and 15 wt.% (hot-press) exhibited optimum room temperature conductivity ( σ) values ~ 2.5 × 10 − 4 S cm − 1 and ~ 1.4 × 10 − 4 S cm − 1 , respectively. Two maxima appeared in the SiO 2 concentration dependent conductivity plot for hot-pressed NCPE films which are discussed in the light of an existing two percolation threshold model.