forsyth-passivationbehaviourof-2018.pdf (1.86 MB)
Passivation behaviour of aluminium current collector in ionic liquid alkyl carbonate (hybrid) electrolytes
journal contribution
posted on 2018-01-01, 00:00 authored by Sowmiya Theivaprakasam, Gaetan Girard, Patrick HowlettPatrick Howlett, Maria ForsythMaria Forsyth, Sagar Mitra, Douglas MacFarlaneThe compatibility of current collectors with the electrolyte plays a major role in the overall performance of lithium batteries, critical to obtain high storage capacity as well as excellent capacity retention. In lithium-ion batteries, in particular with cathodes that operate at high voltage such as lithium nickel cobalt manganese oxide, the cathodic current collector is aluminium and it is subjected to high oxidation potentials (>4 V vs. Li/Li+). As a result, the composition of the electrolyte needs to be carefully designed in order to stabilise the battery performance as well as to protect the current collectors against corrosion. This study examines the role of a hybrid electrolyte composed of an ionic liquid (N-methyl-N-propyl pyrrolidinium bis(trifluoromethanesulfonyl)imide or N-methyl-N-propyl pyrrolidinium bis(fluorosulfonyl)imide) and a conventional electrolyte mixture (LiPF6 salt and alkyl carbonate solvents) with correlation to their electrochemical behaviour and corrosion inhibition efficiency. The hybrid electrolyte was tested against battery grade aluminium current collectors electrochemically in a three-electrode cell configuration and the treated aluminium surface was characterised by SEM/EDXS, optical profilometry, FTIR, and XPS analysis. Based on the experimental results, the hybrid electrolytes allow an effective and improved passivation of aluminium and lower the extent of aluminium dissolution in comparison with the conventional lithium battery electrolytes and the neat ionic liquids at high anodic potentials (4.7 V vs. Li/Li+). The mechanism of passivation behaviour is also further investigated. These observations provide a potential direction for developing improved hybrid electrolytes, based on ionic liquids, for higher energy density devices.
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Journal
npj Materials DegradationVolume
2Issue
1Article number
13Publisher
Nature Publishing Group [Springer Nature]Location
London, Eng.Publisher DOI
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ISSN
2397-2106eISSN
2397-2106Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2018, The AuthorsUsage metrics
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