Inertness of titanium dioxide nanofillers in polyethylene oxide and lithium perchlorate polymer electrolytes

Abstract The thermal properties, morphology and dielectric relaxation of poly(ethylene oxide) (PEO) with the incorporation of titanium dioxide (TiO 2 ) nanofiller with and without the addition of lithium perchlorate (LiClO 4 ) systems prepared via solution casting technique were studied. The characteristics were investigated from an empirical perspective by a thorough sample characterisation using differential scanning calorimetry (DSC), polarized optical microscope (POM) and electrochemical impedance spectroscopy (EIS). The results indicate that the incorporation of TiO 2 nanofiller into the PEO and PEO-LiClO 4 systems results in immiscible systems. Although the initial addition of TiO 2 lower the glass transition temperature ( T g ), further increases in TiO 2 content produce negligible changes in T g , change in heat capacity (Δ C P ), crystallinity ( X * ), and the apparent melting temperature ( T m ). This indicates that TiO 2 has only minimal influence on the thermal properties of PEO matrix. The micrographs of POM confirm that the fibrillose structures of PEO spherulites are mostly unaffected by the inclusion of nanofiller in the PEO and PEO-LiClO 4 systems. Besides, the conductivity of the PEO-LiClO 4 -TiO 2 systems also remains consistent with the addition of TiO 2 . This indicates that the incorporation of TiO 2 did not affect the PEO-LiClO 4 matrix. The conductivity of the PEO-LiClO 4 -TiO 2 system is mainly contributed from the molecular interaction of the charged entities of PEO-LiClO 4 rather than from the interaction between TiO 2 and PEO-LiClO 4 . Therefore, under the experimental conditions of this work, the addition of TiO 2 would not provide a significant influence the thermal, morphological and dielectric properties of PEO polymer electrolytes.