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Title: Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes

Abstract

The quest for the development of rechargeable lithium-metal batteries has attracted vigorous worldwide research efforts because this system offers the highest theoretical specific energy [1]. For this to be achieved, the repetitive deposition and stripping of lithium must be close to fully reversible. Thus, alternative electrolytes have been investigated, such as the room-temperature ionic liquid (RTILs). Lithium can be cycled with a high degree of reversibility with efficiencies exceeding 99% using systems based on N-methyl N-alkyl pyrrolidinium (P{sub 1X}{sup +}) combined with the TFSI anion [2]. More recent efforts have been directed towards systems based on P{sub 1X}{sup +} cations with the FSI anion and appear to be even more promising [3,4]. In this work, we discuss to what extent RTILs based on P{sub 1X}{sup +} cations with TFSI or FSI anions can be used as electrolytes for rechargeable Li batteries. In particular, their physical and chemical properties are thoroughly discussed so as to explain the difference observed in their electrochemical behavior. Although these two systems seem to be stable against lithium, their compatibilities with cathode materials require full assessment as well. Thus, various manganese oxide cathodes are investigated in this study. Strategies to minimize cathode dissolution are also debated,more » such as the substitution of part of the manganese for titanium.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE. Assistant Secretary for Energy Efficiency andRenewable VehicleTechnologies
OSTI Identifier:
929488
Report Number(s):
LBNL-63000-Ext.-Abs.
R&D Project: 500302; BnR: VT0301030; TRN: US200813%%212
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: 212th Electrochemical Society Meeting,Washington, DC, Oct 7-12, 2007
Country of Publication:
United States
Language:
English
Subject:
25; ANIONS; CATHODES; CATIONS; CHEMICAL PROPERTIES; COMPATIBILITY; DEPOSITION; DISSOLUTION; ELECTRODES; ELECTROLYTES; LITHIUM; MANGANESE; MANGANESE OXIDES; TITANIUM

Citation Formats

Saint, Juliette A., Shin, Joon-Ho, Best, Adam, Hollenkamp,Anthony, Kerr, John, and Doeff, Marca M. Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes. United States: N. p., 2007. Web.
Saint, Juliette A., Shin, Joon-Ho, Best, Adam, Hollenkamp,Anthony, Kerr, John, & Doeff, Marca M. Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes. United States.
Saint, Juliette A., Shin, Joon-Ho, Best, Adam, Hollenkamp,Anthony, Kerr, John, and Doeff, Marca M. Wed . "Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes". United States. doi:. https://www.osti.gov/servlets/purl/929488.
@article{osti_929488,
title = {Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes},
author = {Saint, Juliette A. and Shin, Joon-Ho and Best, Adam and Hollenkamp,Anthony and Kerr, John and Doeff, Marca M.},
abstractNote = {The quest for the development of rechargeable lithium-metal batteries has attracted vigorous worldwide research efforts because this system offers the highest theoretical specific energy [1]. For this to be achieved, the repetitive deposition and stripping of lithium must be close to fully reversible. Thus, alternative electrolytes have been investigated, such as the room-temperature ionic liquid (RTILs). Lithium can be cycled with a high degree of reversibility with efficiencies exceeding 99% using systems based on N-methyl N-alkyl pyrrolidinium (P{sub 1X}{sup +}) combined with the TFSI anion [2]. More recent efforts have been directed towards systems based on P{sub 1X}{sup +} cations with the FSI anion and appear to be even more promising [3,4]. In this work, we discuss to what extent RTILs based on P{sub 1X}{sup +} cations with TFSI or FSI anions can be used as electrolytes for rechargeable Li batteries. In particular, their physical and chemical properties are thoroughly discussed so as to explain the difference observed in their electrochemical behavior. Although these two systems seem to be stable against lithium, their compatibilities with cathode materials require full assessment as well. Thus, various manganese oxide cathodes are investigated in this study. Strategies to minimize cathode dissolution are also debated, such as the substitution of part of the manganese for titanium.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 16 00:00:00 EDT 2007},
month = {Wed May 16 00:00:00 EDT 2007}
}

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  • The possibility of using electrolyte systems based on roomtemperature ionic liquids (RTILs) in lithium battery configurations isdiscussed. The nonflammability and wide voltage windows of RTIL-basedsystems are attractive potential advantages, which may ultimately lead tothe development of safer, higher energy density devices than arecurrently available. An evaluation of the compatibility of theseelectrolyte systems with candidate electrodes is critical for furtherprogress. A comparison of the electrochemical behavior of Li/RTIL/LixMnO2and LixTi0.11Mn0.89O2 cells with those containing conventional carbonatesolutions is presented and discussed in terms of the physical propertiesof two RTIL systems and their interactions with the cathodes. Strategiesto improve performance and minimize cathode dissolutionmore » arepresented.« less
  • Large gold nanosheets and small gold polyhedra have been successfully synthesized in room-temperature ionic liquids (ILs) by an ionothermal reduction of HAuCl{sub 4} under N{sub 2} atmosphere, without using any additives. The effect of the organic cation on the final morphologies of the gold particles has been studied, and a series of pyrrolidinium-, imidazolium-, and quaternary amine-based ionic liquids have been investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements. Our results show that these ILs favor the anisotropic growth of gold by acting as template agents and that only gold microspheres can be obtained with the ILmore » containing a reductive functionality.« less
  • Using molecular dynamics simulations, the melting points and liquid phase dynamic properties were studied for four alkyl-imidazolium-based ionic liquids, 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-n-butyl-2,3-dimethylimidazolium hexafluorophosphate ([BMMIM][PF6]), 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIM][PF6]), and 1-ethyl-2,3-dimethylimidazolium hexafluorophosphate ([EMMIM][PF6]), respectively. Experimentally it has been observed that the substitution of a methyl group for a hydrogen at the C2 position of the cation ring leads to an increase in both the melting point and liquid phase viscosity, contrary to arguments that had been made regarding associations between the ions. The melting points of the four ionic liquids were accurately predicted using simulations, as were the trends in viscosity.more » The simulation results show that the origin of the effect is mainly entropic, although enthalpy also plays an important role.« less
  • A new series of ten different asymmetrical 1-dodecyl-3-alkyl-triazolium bromides, [C 12C nTr][Br], has been synthesized and their mesomorphic behavior studied by DSC (differential scanning calorimetry), POM (polarizing optical microscopy) and SAXS (small angle X-ray scattering). The influence of the chain length of the triazolium salts is investigated to explore the effect of asymmetric substitution on the phase behaviour of these compounds. For that reason, the length of one alkyl chain was varied from 14 to 1 carbon atoms (n = 14, 12, 10, 8–4, 2, 1) while the other alkyl chain was kept at 12 carbon. Single crystal X-ray structuremore » analysis of compounds [C 12C 12Tr][Br] and [C 12C 5Tr][Br] reveal that the cations adopt a U-shaped conformation with head-to-head arranged triazolium cores. In contrast, for [C 12C 1Tr][Br], a rod like shape of the cation with interdigitated alkyl chains is found. All investigated compounds are thermotropic liquid crystals. Higher ordered smectic phases, smectic C as well as smectic A phases were found depending on the chain length of the cation. Moreover, the clearing point temperature decreases with decreasing chain length with exception for the n-dodecyl-3-alkyltrizoliumbromides with the two shortest alkyl chains, [C 12C 2Tr][Br] and [C 12C 1Tr][Br], which present higher clearing temperatures (86 and 156 °C) and are structurally distinctly different.« less
  • The room-temperature molten salts possess a number of unique properties that make them ideal battery electrolytes. In particular, they are nonflammable, nonvolatile, and chemically inert, and they display wide electrochemical windows, high inherent conductivities, and wide thermal operating ranges. Although the ionic liquids have excellent characteristics, the chemical and electrochemical properties of desirable battery electrode materials are not well understood in these electrolytes. The research has focused on rechargeable electrodes and has included work on metallic lithium and sodium anodes in buffered neutral chloroaluminate melts, graphite-intercalation electrodes in neutral chloroaluminate and non-chloroaluminate melts, and silane-imidazole polymeric cathodes in acidic chloroaluminatemore » melts. This paper will provide an overview of the research in these areas.« less