Dresden 2017 – wissenschaftliches Programm
CPP 61.5: Vortrag
Donnerstag, 23. März 2017, 16:00–16:15, ZEU 114
1H and 7Li NMR Diffusion and Relaxation measurements of PPG-LiClO4 polymer electrolytes — •Simon Becker and Michael Vogel — Institut für Festkörperphysik, TU Darmstadt, Germany
Polymer electrolytes have been studied since the 1970s as applications for electrical devices because of low costs and mechanical flexibility. To understand effects of polymer-ion couplings on the charge transport in these materials, we use 1 H and 7 Li NMR. Moreover, we employ relaxometry and diffusometry methods to investigate dynamics on local and mesoscopic scales, respectively. We focus on mixtures of poly(propylene) glycol with lithium perchlorate in various concentrations. For these samples 1 H and 7 Li relaxation measurements revealed a strong slow down of segmental motion and ion dynamics with increasing salt concentration. In particular a linear relation between the position of the temperature-dependent 1 H T1 -minimum and the ion:monomer fraction was observed for the polymer backbone protons. The methyl group spin-lattice relaxation was unaffected by the salt content. The diffusion measurements showed a VFT behaviour of the polymer with reduced diffusivity and fragility for high salt concentrations.