Enhancement of Ionic Conductivity of PEO Based Polymer Electrolyte by the Addition of Nanosize Ceramic Powders

The ionic conductivity of polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) has been improved by the addition of nanosize ceramic powders (TiO₂ and Al₂O₃). The PEO based solid polymer electrolytes were prepared by the solution-casting method. Electrochemical measurement shows that the 10 wt% TiO₂ PEO-LiClO₄ polymer electrolyte has the best ionic conductivity (about 10⁻⁴ S cm⁻¹ at 40–60 °C). The lithium transference number of the 10 wt% TiO₂ PEO-LiClO₄ polymer electrolyte was measured to be 0.47, which is much higher than that of bare PEO polymer electrolyte. Ac impedance testing shows that the interface resistance of ceramic-added PEO polymer electrolyte is stable. Linear sweep voltammetry measurement shows that the PEO polymer electrolytes are electrochemically stable in the voltage range of 2.0–5.0 V versus a Li/Li⁺ reference electrode.