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Title: Interfacial behavior of polymer electrolytes

Abstract

Evidence is presented concerning the effect of surfaces on the segmental motion of PEO-based polymer electrolytes in lithium batteries. For dry systems with no moisture the effect of surfaces of nano-particle fillers is to inhibit the segmental motion and to reduce the lithium ion transport. These effects also occur at the surfaces in composite electrodes that contain considerable quantities of carbon black nano-particles for electronic connection. The problem of reduced polymer mobility is compounded by the generation of salt concentration gradients within the composite electrode. Highly concentrated polymer electrolytes have reduced transport properties due to the increased ionic cross-linking. Combined with the interfacial interactions this leads to the generation of low mobility electrolyte layers within the electrode and to loss of capacity and power capability. It is shown that even with planar lithium metal electrodes the concentration gradients can significantly impact the interfacial impedance. The interfacial impedance of lithium/PEO-LiTFSI cells varies depending upon the time elapsed since current was turned off after polarization. The behavior is consistent with relaxation of the salt concentration gradients and indicates that a portion of the interfacial impedance usually attributed to the SEI layer is due to concentrated salt solutions next to the electrode surfacesmore » that are very resistive. These resistive layers may undergo actual phase changes in a non-uniform manner and the possible role of the reduced mobility polymer layers in dendrite initiation and growth is also explored. It is concluded that PEO and ethylene oxide-based polymers are less than ideal with respect to this interfacial behavior.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Environmental Energy Technologies Division
OSTI Identifier:
925749
Report Number(s):
LBNL-53141
Journal ID: ISSN 0013-4686; ELCAAV; TRN: US200810%%97
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Electrochimica Acta
Additional Journal Information:
Journal Volume: 50; Journal Issue: 2-3 SI; Related Information: Journal Publication Date: 12/30/2004; Journal ID: ISSN 0013-4686
Country of Publication:
United States
Language:
English
Subject:
25; CAPACITY; CARBON BLACK; DENDRITES; ELECTRODES; ELECTROLYTES; ETHYLENE; FILLERS; IMPEDANCE; LITHIUM; LITHIUM IONS; MOISTURE; PLASMA SWITCHES; POLARIZATION; POLYMERS; RELAXATION; TRANSPORT

Citation Formats

Kerr, John, Kerr, John B, Han, Yong Bong, Liu, Gao, Reeder, Craig, Xie, Jiangbing, and Sun, Xiaoguang. Interfacial behavior of polymer electrolytes. United States: N. p., 2003. Web.
Kerr, John, Kerr, John B, Han, Yong Bong, Liu, Gao, Reeder, Craig, Xie, Jiangbing, & Sun, Xiaoguang. Interfacial behavior of polymer electrolytes. United States.
Kerr, John, Kerr, John B, Han, Yong Bong, Liu, Gao, Reeder, Craig, Xie, Jiangbing, and Sun, Xiaoguang. 2003. "Interfacial behavior of polymer electrolytes". United States. https://www.osti.gov/servlets/purl/925749.
@article{osti_925749,
title = {Interfacial behavior of polymer electrolytes},
author = {Kerr, John and Kerr, John B and Han, Yong Bong and Liu, Gao and Reeder, Craig and Xie, Jiangbing and Sun, Xiaoguang},
abstractNote = {Evidence is presented concerning the effect of surfaces on the segmental motion of PEO-based polymer electrolytes in lithium batteries. For dry systems with no moisture the effect of surfaces of nano-particle fillers is to inhibit the segmental motion and to reduce the lithium ion transport. These effects also occur at the surfaces in composite electrodes that contain considerable quantities of carbon black nano-particles for electronic connection. The problem of reduced polymer mobility is compounded by the generation of salt concentration gradients within the composite electrode. Highly concentrated polymer electrolytes have reduced transport properties due to the increased ionic cross-linking. Combined with the interfacial interactions this leads to the generation of low mobility electrolyte layers within the electrode and to loss of capacity and power capability. It is shown that even with planar lithium metal electrodes the concentration gradients can significantly impact the interfacial impedance. The interfacial impedance of lithium/PEO-LiTFSI cells varies depending upon the time elapsed since current was turned off after polarization. The behavior is consistent with relaxation of the salt concentration gradients and indicates that a portion of the interfacial impedance usually attributed to the SEI layer is due to concentrated salt solutions next to the electrode surfaces that are very resistive. These resistive layers may undergo actual phase changes in a non-uniform manner and the possible role of the reduced mobility polymer layers in dendrite initiation and growth is also explored. It is concluded that PEO and ethylene oxide-based polymers are less than ideal with respect to this interfacial behavior.},
doi = {},
url = {https://www.osti.gov/biblio/925749}, journal = {Electrochimica Acta},
issn = {0013-4686},
number = 2-3 SI,
volume = 50,
place = {United States},
year = {Tue Jun 03 00:00:00 EDT 2003},
month = {Tue Jun 03 00:00:00 EDT 2003}
}