Electrical transport in PEO-NaI-NASICON nanocomposites: An assessment using impedance and X-Ray absorption spectroscopy

Abstract

Present investigation focuses on conductivity-structure correlation in NaTi2(PO4)3 (NTP) embedded novel hybrid solid polymer composites prepared in a wide range of composition 10NaI-90(PEO1-xNTPx) (wt%), for 0 ≤ x ≤ 0.7. A maximum ionic conductivity of ˜ 4 × 10-5 Ω-1 cm-1 has been achieved with x = 0.7 at 40 °C that is higher than that of the host PEO-NaI (⁓ 5 × 10-7 Ω-1 cm-1) system by at least two orders of magnitude. Elemental mapping during field emission scanning electron microscopy suggests homogeneous distribution of NTP in the compositions. Trends of K-edge energies of oxygen in the X-Ray absorption near edge structure spectra have been found to be useful in proposing a tentative mechanism for ionic transport. Structural and impedance spectroscopy investigations suggest that for low NTP content, salt ions prefer to move through polymer. However, for higher content, surface states of NASICON at polymer-NTP interface facilitate the ionic conduction.