Solid-state C-13 NMR and DFT quantum-chemical study of polymer electrolyte poly(2-ethyl-2-oxazoline)/AgCF3SO3

Abstract

Solid-state C-13 NMR spectra and DFT calculations confirmed that dominant interaction in POZ/AgCF3SO3 polymer electrolyte is coordination between carbonyl groups and silver cation. Lower shielding of POZ carbonyl carbons and to a smaller extent also adjacent methylene carbons was found for the POZ/AgCF3SO3 complex in comparison with neat POZ, both in C-13 NMR spectra and by DFT calculations on model systems. The POZ/AgCF3SO3 complex has a defined stoichiometry: two POZ monomeric units per one AgCF3SO3. A close contact between both components was determined from the Lee-Goldburg cross-polarization H-1 -> C-13 dynamics. The shorter C-13 spin-lattice relaxation times in the stoichiometric POZ/AgCF3SO3 sample in comparison with neat POZ indicate a formation of small amount (similar to 0.1%) of paramagnetic neutral silver.