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Title: Relaxation in polymer electrolytes on the nanosecond timescale.

Abstract

The relation between mechanical and electrical relaxation in polymer/lithium-salt complexes is a fascinating and still unresolved problem in condensed-matter physics, yet has an important bearing on the viability of such materials for use as electrolytes in lithium batteries. At room temperature, these materials are biphasic: they consist of both fluid amorphous regions and salt-enriched crystalline regions. Ionic conduction is known to occur predominantly in the amorphous fluid regions. Although the conduction mechanisms are not yet fully understood, it is widely accepted that lithium ions, coordinated with groups of ether oxygen atoms on single or perhaps double polymer chains, move through re-coordination with other oxygen-bearing groups. The formation and disruption of these coordination bonds must be accompanied by strong relaxation of the local chain structure. Here we probe the relaxation on a nanosecond timescale using quasielastic neutron scattering, and we show that at least two processes are involved: a slow process with a translational character and one or two fast processes with a rotational character. Whereas the former reflects the slowing-down of the translational relaxation commonly observed in polyethylene oxide and other polymer melts, the latter appears to be unique to the polymer electrolytes and has not (to our knowledge) beenmore » observed before. A clear picture emerges of the lithium cations forming crosslinks between chain segments and thereby profoundly altering the dynamics of the polymer network.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
942878
Report Number(s):
ANL/MSD/JA-35534
Journal ID: ISSN 0028-0836; TRN: US0904494
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Nature
Additional Journal Information:
Journal Volume: 405; Journal Issue: 6783 ; May 11, 2000; Journal ID: ISSN 0028-0836
Country of Publication:
United States
Language:
ENGLISH
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ELECTROLYTES; LITHIUM; LITHIUM IONS; POLYETHYLENE GLYCOLS; POLYMERS; RELAXATION

Citation Formats

Mao, G., Fernandez-Perea, R., Price, D. L., Saboungi, M.-L., Howells, W. S., Materials Science Division, and Rutherford-Appleton Lab. Relaxation in polymer electrolytes on the nanosecond timescale.. United States: N. p., 2000. Web. doi:10.1038/35012032.
Mao, G., Fernandez-Perea, R., Price, D. L., Saboungi, M.-L., Howells, W. S., Materials Science Division, & Rutherford-Appleton Lab. Relaxation in polymer electrolytes on the nanosecond timescale.. United States. doi:10.1038/35012032.
Mao, G., Fernandez-Perea, R., Price, D. L., Saboungi, M.-L., Howells, W. S., Materials Science Division, and Rutherford-Appleton Lab. Thu . "Relaxation in polymer electrolytes on the nanosecond timescale.". United States. doi:10.1038/35012032.
@article{osti_942878,
title = {Relaxation in polymer electrolytes on the nanosecond timescale.},
author = {Mao, G. and Fernandez-Perea, R. and Price, D. L. and Saboungi, M.-L. and Howells, W. S. and Materials Science Division and Rutherford-Appleton Lab.},
abstractNote = {The relation between mechanical and electrical relaxation in polymer/lithium-salt complexes is a fascinating and still unresolved problem in condensed-matter physics, yet has an important bearing on the viability of such materials for use as electrolytes in lithium batteries. At room temperature, these materials are biphasic: they consist of both fluid amorphous regions and salt-enriched crystalline regions. Ionic conduction is known to occur predominantly in the amorphous fluid regions. Although the conduction mechanisms are not yet fully understood, it is widely accepted that lithium ions, coordinated with groups of ether oxygen atoms on single or perhaps double polymer chains, move through re-coordination with other oxygen-bearing groups. The formation and disruption of these coordination bonds must be accompanied by strong relaxation of the local chain structure. Here we probe the relaxation on a nanosecond timescale using quasielastic neutron scattering, and we show that at least two processes are involved: a slow process with a translational character and one or two fast processes with a rotational character. Whereas the former reflects the slowing-down of the translational relaxation commonly observed in polyethylene oxide and other polymer melts, the latter appears to be unique to the polymer electrolytes and has not (to our knowledge) been observed before. A clear picture emerges of the lithium cations forming crosslinks between chain segments and thereby profoundly altering the dynamics of the polymer network.},
doi = {10.1038/35012032},
journal = {Nature},
issn = {0028-0836},
number = 6783 ; May 11, 2000,
volume = 405,
place = {United States},
year = {2000},
month = {5}
}