Iodine L-Edge X-Ray Absorption Fine Structure Studies of Polymer-Iodide Salt Complexes

Abstract
We report measurements of extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) of the L edge of iodine in the polymer electrolytes PPO8NaI, PPO8LiI, and PEI10NaI. The EXAFS indicates a disordered environment for the iodine, although the PEI complex does exhibit several weak oscillations indicating a significantly less disordered environment of the anion in this complex. The XANES results suggest that the iodine is becoming more covalent in the sequence PPO8LiI-PEI10NaI-PPO8NaI, implying there are substantial interactions between the anions and cations.