Comparison of the ionic conductivity properties of microporous and mesoporous MOFs infiltrated with a Na-ion containing IL mixture
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
IL@MOF (IL: ionic liquid; MOF: metal–organic framework) materials have been proposed as a candidate for solid-state electrolytes, combining the inherent non-flammability and high thermal and chemical stability of the ionic liquid with the host–guest interactions of the MOF. In this work, we compare the structure and ionic conductivity of a sodium ion containing IL@MOF composite formed from a microcrystalline powder of the zeolitic imidazolate framework (ZIF), ZIF-8 with a hierarchically porous sample of ZIF-8 containing both micro- and mesopores from a sol–gel synthesis. Although the crystallographic structures were shown to be the same by X-ray diffraction, significant differences in particle size, packing and morphology were identified by electron microscopy techniques which highlight the origins of the hierarchical porosity. After incorporation of Na0.1EMIM0.9TFSI (abbreviated to NaIL; EMIM = 1-ethyl-3-methylimidazolium; TFSI = bis(trifluoromethylsulfonyl)imide), the hierarchically porous composite exhibited a 40% greater filling capacity than the purely microporous sample which was confirmed by elemental analysis and digestive proton NMR. Finally, the ionic conductivity properties of the composite materials were probed by electrochemical impedance spectroscopy. The results showed that despite the 40% increased loading of NaIL in the NaIL@ZIF-8micro sample, the ionic conductivities at 25 °C were 8.4 × 10−6 and 1.6 × 10−5 S cm−1 for NaIL@ZIF-8meso and NaIL@ZIF-8micro respectively. These results exemplify the importance of the long range, continuous ion pathways contributed by the microcrystalline pores, as well as the limited contribution from the discontinuous mesopores to the overall ionic conductivity.
Date Issued
2020-11-28
Date Acceptance
2020-11-03
Citation
Dalton Transactions: an international journal of inorganic chemistry, 2020, 49 (44), pp.15914-15924
ISSN
1477-9226
Publisher
Royal Society of Chemistry
Start Page
15914
End Page
15924
Journal / Book Title
Dalton Transactions: an international journal of inorganic chemistry
Volume
49
Issue
44
Copyright Statement
© The Royal Society of Chemistry 2020. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.
License URL
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000590136500036&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Chemistry, Inorganic & Nuclear
Chemistry
METAL-ORGANIC FRAMEWORK
ZIF-8
TEMPERATURE
PERFORMANCE
CONDUCTORS
DIFFUSION
LIQUIDS
CO2
CONSEQUENCES
ENHANCEMENT
Publication Status
Published
Date Publish Online
2020-11-03