Lithium ion conduction and ion-polymer interaction in poly(vinyl pyrrolidone) based electrolytes blended with different plasticizers

Poly(ethylene oxide), poly(vinyl pyrrolidone) (PEO/PVP), lithium perchlorate salt (LiClO4) and different plasticizer based, gel polymer electrolytes were prepared by the solvent casting technique. XRD results show that the crystallinity decreases with the addition of different plasticizers. Consequently, there is an enhancement in the amorphousity of the samples responsible for the process of ion transport. FTIR spectroscopy is used to characterize the structure of the polymer and confirms the complexation of plasticizer with host polymer matrix. The ionic conductivity has been calculated using the bulk impedance obtained through impedance spectroscopy. Among the various plasticizers, the ethylene carbonate (EC) based complex exhibits a maximum ionic conductivity value of the order of 2.7279 × 10−4 S cm−1. Thermal stability of the prepared electrolyte films shows that they can be used in batteries at elevated temperatures. PEO (72%)/PVP (8%)/LiClO4 (8%)/EC (12%) has the maximum ionic conductivity value which is supported by the lowest optical band gap and lowest intensity in photoluminescence spectroscopy near 400–450 nm. Two and three dimensional topographic images of the sample having a maximum ionic conductivity show the presence of micropores.

Graphical abstractThis paper reports on the gel polymer electrolytes based on the PEO/PVP/LiClO4 complex by the addition of different plasticizers using a well known solvent casting technique.Figure optionsDownload full-size imageDownload as PowerPoint slide