Single crystalline TiO2 nanorods as effective fillers for lithium ion conducting PVdF-HFP based composite polymer electrolytes

Abstract

Phase pure single crystalline TiO₂ nanorods were prepared by a hydrothermal route and characterized by XRD, SEM and HRTEM techniques. Comparative studies were made between the PVdF-HFP based composite electrolytes doped with as prepared TiO₂ nanorods (PT) and commercial TiO₂ sub-microns (PTC) as fillers. The 5 wt% of TiO₂ nanorods added composite electrolyte (PT-5) was found to exhibit an electrical conductivity of ∼1.11 × 10⁻² S cm⁻¹ which was two orders higher than the 5 wt% of commercial TiO₂ added system (PTC-5) exhibiting conductivity of ∼1.72 × 10⁻⁴ S cm⁻¹. A temperature dependent conductivity study shows film PT-5 to exhibit an activation energy of 0.26 eV, whereas the film PTC-5 exhibits a higher value of 0.45 eV. The influences of the filler size/morphology on the structural and electrical properties of the electrolytes were explored through XRD, FTIR, AC impedance, thermal and mechanical stability studies. A significant enhancement in the mechanical stability of the membrane was achieved by using nanofillers.