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Preparation and characterization of gel polymer electrolytes using poly(ionic liquids) and high lithium salt concentration ionic liquids

journal contribution
posted on 01.01.2017, 00:00 authored by Xiaoen WangXiaoen Wang, Haijin Zhu, Gaetan Girard, Ruhamah Yunis, D R Macfarlane, D Mecerreyes, A J Bhattacharyya, Patrick HowlettPatrick Howlett, Maria ForsythMaria Forsyth
© 2017 The Royal Society of Chemistry. Polymerized ionic liquids or poly(ionic liquids) (polyILs) have been considered as promising hosts for fabrication of gel polymer electrolytes (GPEs) containing ionic liquids. In this work, a novel GPE based on a polyIL, poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMA TFSI), and a high lithium-concentration phosphonium ionic liquid, trimethyl(isobutyl)phosphonium bis(fluorosulfonyl)imide (P 111i4 FSI), is prepared. The composition-dependent behaviour of the GPEs is investigated by differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS) and solid-state nuclear magnetic resonance (solid-state NMR). The effects of Al 2 O 3 nano-particles on the polymer electrolyte properties are also discussed. It is shown that the introduction of high lithium-concentration ionic liquids into the polyIL can effectively decrease the glass transition temperature (T g ) of the resulting GPE, leading to improved ion dynamics and higher ionic conductivity. The Al 2 O 3 nano-particles effectively enhanced the mechanical stability of the GPEs. Most importantly, although adding PDADMA TFSI to the ionic liquids decreases the diffusion coefficient of both Li + and anions, a greater decrease in the anion diffusion is observed, resulting in a higher Li + transport number (as evaluated by NMR) than that seen in the original ILs. Finally, a highly conductive free-standing GPE membrane is fabricated, and extremely stable lithium symmetrical cell performance is demonstrated.

History

Journal

Journal of Materials Chemistry A

Volume

5

Issue

45

Pagination

23844 - 23852

Publisher

Royal Society of Chemistry

Location

Cambridge, Eng.

ISSN

2050-7488

eISSN

2050-7496

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2017, The Royal Society of Chemistry