Impedance, structural and thermal analyses of polyvinyl alcohol/polyvinyl pyrrolidone blend incorporated with Li+ ions for lithium-ion batteries

Abstract

As an attempt to pave the way for developing the lithium polymer batteries, (PVA/PVP) blend filled with different weight percentages of lithium perchlorate (LiClO4) was prepared using solution casting technique. Morphological and microstructural properties of the SPE were studied via SEM, XRD and FT-IR spectroscopy, where its semicrystalline nature was confirmed. Thermal stability, dielectric properties, the relaxation dynamics inside the current system and electrical conduction behavior of the synthesized films were prudently studied. The electrical conduction mechanism inside the samples was interpreted using the Jonscher's double power law. Activation energy was calculated using Coats-Redfern and Broido models. The oblate semicircular arc observed in Nyquist curves indicated the non-Debye behavior of ions relaxation in the present SPE samples. This behavior was assured by the evident decrease in intensity of the M'' relaxation peak. The complex impedance analysis not only verified the dominance of the resistive nature over the capacitance but also demonstrated that the conduction in the SPE was only produced by the induced ions. Mixing LiClO4 filler at 8 wt.% with the PVA/PVP host matrix had a fruitful effect on amelioration in the structural, thermal and dielectric properties of the prepared composite sample. This beneficial enhancement recommends the (PVA/PVP)/LiClO4 composite to be used in fabricating lithium polymer batteries and energy storage devices with high performance.