Impact of shape (nanofiller vs. nanorod) of TiO2 nanoparticle on free-standing solid polymeric separator for energy storage/conversion devices

Abstract

We report the investigation on examining the impact of nanofiller (NF)- versus nanorod (NR)-shaped titanium oxide (TiO2) nanoparticle on the structural, electrochemical, transport, thermal, and dielectric properties of the solid polymer electrolyte (SPE). Thin SPE films comprising of poly(ethylene oxide), sodium hexafluorophosphate, and dispersed with TiO2 NF, TiO2 NR (synthesized by hydrothermal route) has been prepared via solution cast technique. The shape of nanoparticle influences the morphological and structural properties as observed in field emission scanning electron microscope and X-ray diffraction analysis. The highest ionic conductivity was exhibited by the NR dispersed system and is higher than NF dispersed system for all recorded concentration consistently. It is attributed to the formation of the long-range conductive path with NR when compared with NF. In addition, the electrochemical stability window is much higher (~5 V) than the NF-doped system. Furthermore, the dielectric properties of SPE were investigated and fitted in the complete frequency window (1 Hz–1 MHz; T = 40–100 °C @ 10 °C). It is observed that the NR dispersed system shows higher dielectric strength and low relaxation time with respect to NF dispersed system. The results suggest that the NR dispersed SPE possess enhanced properties and is more appropriate for an application in high energy density solid‐state Na ion batteries. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47361.