skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate

Abstract

Network single ion conductors (NSICs) based on comb-branch polyepoxide ethers and lithium bis(allylmalonato) borate have been synthesized and thoroughly characterized by means of ionic conductivity measurements, electrochemical impedance and by dynamic mechanical analysis (DMA). The materials have been tested as battery electrolytes by cycling in symmetrical Li/Li half cells and in Li/V{sub 6}O{sub 13} full cells in which the NSIC was used as both binder and electrolyte in the cathode electrode and as the electrolyte separator membrane,. The substitution of the trimethylene oxide (TMO) unit into the side chains in place of ethylene oxide (EO) units increased the polymerion mobility (lower glass transition temperature). However, the ionic conductivity was nearly one and half orders of magnitude lower than the corresponding pure EO based single ion conductor at the same salt concentration. This effect may be ascribed to the lower dielectric constant of the TMO side chains that result in a lower concentration of free conducting lithium cations. For a highly cross-linked system (EO/Li=20), only 47 wt% plasticizing solvent (ethylene carbonate (EC)/ethyl methyl carbonate (EMC), 1/1 by wt) could be taken up and the ionic conductivity was only increased by one order of magnitude over the dry polyelectrolyte while for amore » less densely crosslinked system (EO/Li=80), up to 75 wt% plasticizer could be taken up and the ionic conductivity was increased by nearly two orders of magnitude. A Li/Li symmetric cell that was cycled at 85 C at a current density of 25{micro}Acm{sup -2} showed no concentration polarization or diffusional relaxation, consistent with a lithium ion transference number of one. However, both the bulk and interfacial impedances increased after 20 cycles, apparently due to continued cross-linking reactions within the membrane and on the surface of the lithium electrodes. A Li/V{sub 6}O{sub 13} full cell constructed using a single ion conductor gel (propylene carbonate (PC)/EMC, 1/1 in wt) was cycled at 25 C at a current density of 25 {micro}A cm{sup -2} and showed an initial capacity of 268 mAh g{sup -1} of V{sub 6}O{sub 13}, which stabilized at around 200 mAh g{sup -1} after the first 20 cycles. In the course of DMA measurements on the network single ion conductors it was found that besides the main glass transition ({alpha} transition) there was a distinct secondary glass transition ({beta} transition ) for network single ion conductors having five EO units in the side chains while this (the secondary transition) was not clearly visible in the network single ion conductors with shorter side chains (two, three and four EO units). The main glass transition ({alpha} transition) was attributed to the backbone network structure of the single ion conductors and secondary glass transition ({beta} transition) appeared to be due to the complexation of lithium by the side-chain chains. Both the main glass transition and the secondary transition were found to shift to higher temperature with increasing salt concentration.« less

Authors:
;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE. Assistant Secretary for Energy Efficiency andRenewable Energy. Office of the FreedomCAR and Vehicle TechnologiesProgram; National Aeronautics and Space Administration. Payload EquipmentRestraint System
OSTI Identifier:
891341
Report Number(s):
LBNL-58602
R&D Project: 473003; BnR: VT0301030; TRN: US0605367
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Macromolecules; Journal Volume: 39; Journal Issue: 1; Related Information: Journal Publication Date: 01/10/2006
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 74 ATOMIC AND MOLECULAR PHYSICS; BORATES; CARBONATES; CATHODES; CATIONS; ELECTRODES; ELECTROLYTES; ETHYLENE; CURRENT DENSITY; ETHERS; IONIC CONDUCTIVITY; LITHIUM; LITHIUM IONS; PERMITTIVITY; PLASTICIZERS; POLARIZATION; PROPYLENE; SOLVENTS; SYNTHESIS

Citation Formats

Sun, Xiao-Guang, and Kerr, John B. Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate. United States: N. p., 2004. Web.
Sun, Xiao-Guang, & Kerr, John B. Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate. United States.
Sun, Xiao-Guang, and Kerr, John B. Sun . "Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate". United States. https://www.osti.gov/servlets/purl/891341.
@article{osti_891341,
title = {Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate},
author = {Sun, Xiao-Guang and Kerr, John B.},
abstractNote = {Network single ion conductors (NSICs) based on comb-branch polyepoxide ethers and lithium bis(allylmalonato) borate have been synthesized and thoroughly characterized by means of ionic conductivity measurements, electrochemical impedance and by dynamic mechanical analysis (DMA). The materials have been tested as battery electrolytes by cycling in symmetrical Li/Li half cells and in Li/V{sub 6}O{sub 13} full cells in which the NSIC was used as both binder and electrolyte in the cathode electrode and as the electrolyte separator membrane,. The substitution of the trimethylene oxide (TMO) unit into the side chains in place of ethylene oxide (EO) units increased the polymerion mobility (lower glass transition temperature). However, the ionic conductivity was nearly one and half orders of magnitude lower than the corresponding pure EO based single ion conductor at the same salt concentration. This effect may be ascribed to the lower dielectric constant of the TMO side chains that result in a lower concentration of free conducting lithium cations. For a highly cross-linked system (EO/Li=20), only 47 wt% plasticizing solvent (ethylene carbonate (EC)/ethyl methyl carbonate (EMC), 1/1 by wt) could be taken up and the ionic conductivity was only increased by one order of magnitude over the dry polyelectrolyte while for a less densely crosslinked system (EO/Li=80), up to 75 wt% plasticizer could be taken up and the ionic conductivity was increased by nearly two orders of magnitude. A Li/Li symmetric cell that was cycled at 85 C at a current density of 25{micro}Acm{sup -2} showed no concentration polarization or diffusional relaxation, consistent with a lithium ion transference number of one. However, both the bulk and interfacial impedances increased after 20 cycles, apparently due to continued cross-linking reactions within the membrane and on the surface of the lithium electrodes. A Li/V{sub 6}O{sub 13} full cell constructed using a single ion conductor gel (propylene carbonate (PC)/EMC, 1/1 in wt) was cycled at 25 C at a current density of 25 {micro}A cm{sup -2} and showed an initial capacity of 268 mAh g{sup -1} of V{sub 6}O{sub 13}, which stabilized at around 200 mAh g{sup -1} after the first 20 cycles. In the course of DMA measurements on the network single ion conductors it was found that besides the main glass transition ({alpha} transition) there was a distinct secondary glass transition ({beta} transition ) for network single ion conductors having five EO units in the side chains while this (the secondary transition) was not clearly visible in the network single ion conductors with shorter side chains (two, three and four EO units). The main glass transition ({alpha} transition) was attributed to the backbone network structure of the single ion conductors and secondary glass transition ({beta} transition) appeared to be due to the complexation of lithium by the side-chain chains. Both the main glass transition and the secondary transition were found to shift to higher temperature with increasing salt concentration.},
doi = {},
journal = {Macromolecules},
number = 1,
volume = 39,
place = {United States},
year = {Sun Jul 11 00:00:00 EDT 2004},
month = {Sun Jul 11 00:00:00 EDT 2004}
}