On the ionic diffusive motion in some fluoride doped polymer electrolytes

The ionic diffusive motion (translational and rotational) of cations (NH4+ / H+) and anions (F−/BF4−) in polyethylene oxide (PEO) based polymer electrolytes containing ammonium fluoride (NH4F) and ammonium tetrafluoroborate (NH4BF4) has been studied by 1H and 19F NMR. Long range protonic translational motion has been observed at temperatures above the glass transition temperature (Tg) whereas rotational diffusion of fluoride has been observed in PEO–NH4BF4 at temperatures below Tg. In PEO–NH4BF4, both cations and anions have been found to show translational motion above Tg.