On the Mechanism of Ion Transport through Polyphosphazene Solid Polymer Electrolytes 1: NMR, IR, and Raman Spectroscopic Studies and Computational Analysis of 15N Labeled Polyphosphazenes
Comprehensive investigation of lithium ion complexation with 15N-labeled polyphosphazenes- 15N-poly[bis(2-(2-methoxyethoxy)ethoxy)phosphazene] (15N-MEEP) and 15N-poly-[((2-allylphenoxy)0.12(4-methoxyphenoxy)1.02(2-(2-methoxyethoxy)ethoxy)0.86)phosphazene] (15N-HPP)-was performed by NMR, IR, and Raman spectroscopies. Previous studies characterized the ionic transport through the polymer matrix in terms of "jumps" between neighboring polymer strands utilizing the electron lone pairs of the etherial oxygen nuclei with the nitrogen nuclei on the polyphosphazene backbone not involved. However, noteworthy changes were observed in the NMR, IR, and Raman spectra with the addition of lithium trifluoromethanesulfonate (LiOTf) to the polyphosphazenes. The data indicate that the preferred association for the lithium ion with the polymer is with the nitrogen nuclei, resulting in the formation of a "pocket" with the pendant groups folding around the backbone. NMR temperature-dependent spin-lattice relaxation (T1) studies (13C, 31P, and 15N) indicate significant lithium ion interaction with the backbone nitrogen nuclei. These studies are in agreement with molecular dynamics simulations investigating lithium ion movement within the polyphosphazene matrix.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC07-99ID-13727
- OSTI ID:
- 912152
- Report Number(s):
- INEEL/JOU-00-01514; JACSAT; TRN: US0800288
- Journal Information:
- Journal of the American Chemical Society, Vol. 107, Issue 14; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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