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Title: Mixed-salt Effects on the Ionic Conductivity of Lithium-doped PEO-containing Block Copolymers

Abstract

We demonstrate a simple, yet effective, mixed-salt method to increase the room temperature ionic conductivity of lithium-doped block copolymer electrolyte membranes by suppressing the crystalline phases in the conducting block. We examined a mixed-salt system of LiClO{sub 4} and LiN(SO{sub 2}CF{sub 3}){sub 2} (LiTFSI) doped into a lamellae-forming poly(styrene-b-ethylene oxide) (PS-PEO) diblock copolymer. The domain spacings, morphologies, thermal behavior, and crystalline phases of salt-doped PS-PEO samples were characterized, and the ionic conductivities of block copolymer electrolytes were obtained through ac impedance measurements. Comparing the ionic conductivity profiles of salt-doped PS-PEO samples at different mixed-salt ratios and total salt concentrations, we found that the ionic conductivity at room temperature can be improved by more than an order of magnitude when coinhibition of crystallite growth is promoted by the concerted behavior of the PEO:LiClO{sub 4} and PEO:LiTFSI phases. Additionally, we examined the influence of mixed-salt ratio and total salt concentration on copolymer energetics, and we found that the slope of the effective interaction parameter (x{sub eff}) vs salt concentration in our lamellae-forming PS-PEO system was lower than that reported for a cylinder-forming PS-PEO system due to the balance between chain stretching and salt segregation in the PEO domains.

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1041995
Report Number(s):
BNL-97673-2012-JA
Journal ID: ISSN 0024-9297; TRN: US201212%%406
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 44; Journal Issue: 20; Journal ID: ISSN 0024-9297
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPOLYMERS; ELECTROLYTES; IMPEDANCE; IONIC CONDUCTIVITY; MEMBRANES; PLASMA SWITCHES; SEGREGATION

Citation Formats

Young, W, Albert, J, Schantz, A, and Epps, T. Mixed-salt Effects on the Ionic Conductivity of Lithium-doped PEO-containing Block Copolymers. United States: N. p., 2011. Web. doi:10.1021/ma2013157.
Young, W, Albert, J, Schantz, A, & Epps, T. Mixed-salt Effects on the Ionic Conductivity of Lithium-doped PEO-containing Block Copolymers. United States. https://doi.org/10.1021/ma2013157
Young, W, Albert, J, Schantz, A, and Epps, T. Sat . "Mixed-salt Effects on the Ionic Conductivity of Lithium-doped PEO-containing Block Copolymers". United States. https://doi.org/10.1021/ma2013157.
@article{osti_1041995,
title = {Mixed-salt Effects on the Ionic Conductivity of Lithium-doped PEO-containing Block Copolymers},
author = {Young, W and Albert, J and Schantz, A and Epps, T},
abstractNote = {We demonstrate a simple, yet effective, mixed-salt method to increase the room temperature ionic conductivity of lithium-doped block copolymer electrolyte membranes by suppressing the crystalline phases in the conducting block. We examined a mixed-salt system of LiClO{sub 4} and LiN(SO{sub 2}CF{sub 3}){sub 2} (LiTFSI) doped into a lamellae-forming poly(styrene-b-ethylene oxide) (PS-PEO) diblock copolymer. The domain spacings, morphologies, thermal behavior, and crystalline phases of salt-doped PS-PEO samples were characterized, and the ionic conductivities of block copolymer electrolytes were obtained through ac impedance measurements. Comparing the ionic conductivity profiles of salt-doped PS-PEO samples at different mixed-salt ratios and total salt concentrations, we found that the ionic conductivity at room temperature can be improved by more than an order of magnitude when coinhibition of crystallite growth is promoted by the concerted behavior of the PEO:LiClO{sub 4} and PEO:LiTFSI phases. Additionally, we examined the influence of mixed-salt ratio and total salt concentration on copolymer energetics, and we found that the slope of the effective interaction parameter (x{sub eff}) vs salt concentration in our lamellae-forming PS-PEO system was lower than that reported for a cylinder-forming PS-PEO system due to the balance between chain stretching and salt segregation in the PEO domains.},
doi = {10.1021/ma2013157},
url = {https://www.osti.gov/biblio/1041995}, journal = {Macromolecules},
issn = {0024-9297},
number = 20,
volume = 44,
place = {United States},
year = {2011},
month = {12}
}