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Clarke OJR, Rowley A, Fox RV, Burgess IJ, Atifi A. Nano-Plasticity of an Electrified Ionic Liquid/Electrode Interface: Uncovering Hard-Soft Structuring via Controlled Metal Fill Factor. ACS NANO 2024; 18:14716-14725. [PMID: 38774972 DOI: 10.1021/acsnano.4c03617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Ionic liquids (ILs) nanostructuring at electrified interfaces is of both fundamental and practical interest as these materials are increasingly gaining prominence in energy storage and conversion processes. However, much remains unresolved about IL potential-controlled (re)organization under highly polarized interfaces, mostly due to the difficulty of selectively probing both the distal and proximal surface layers of adsorbed ions. In this work, the structural dynamics of the innermost layer (<10 nm from the surface) were independently interrogated from that of the ionic layers in the sub-surface region (>100 nm from the surface), using an infrared (IR) spectroscopy approach. By tuning the metal fill factor of gold films deposited on conductive metal oxide-modified IR internal reflection elements, the charge-driven (re)structuring of the inner and distal layers of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate is unveiled. Within a relatively wide potential region (∼±1 V) bounding the potential of zero charges, the ionic liquid is shown to undergo a reversible (i.e., soft) reorganization whereby the innermost layer of anions (cations) is exchanged by a layer of cations (anions). Kinetically unhindered changes in the number density of constituent cations and anions largely follow electrostatic expectations in the subsurface region, whereas the innermost layer exhibits a pronounced hysteresis and very slow relaxation. Under larger negative potential bias, IL restructuring is characterized by a highly irreversible (i.e., hard) and intense interfacial densification of the BMPy+ cations, consistent with the formation of nanoscale segregated liquids. The outcomes of this work reveal a plastic IL nanostructuring under a strong electric field.
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Affiliation(s)
- Osai J R Clarke
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Annabel Rowley
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Robert V Fox
- Chemical Systems Department, Idaho National Laboratory, Idaho Falls, Idaho 83415, United States
| | - Ian J Burgess
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Abderrahman Atifi
- Chemical Systems Department, Idaho National Laboratory, Idaho Falls, Idaho 83415, United States
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Mahapatra A, Samantara AK, Barik S, Sahoo MK, Behera JN, Sarkar M. Insight into the structure and transport properties of pyrrolidinium-based geminal dicationic-organic ionic crystals: inravelling the role of alkyl-chain length. SOFT MATTER 2023; 19:3510-3518. [PMID: 37145490 DOI: 10.1039/d3sm00040k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The present study has been undertaken with an aim to design and develop safer and more efficient all solid-state electrolytes, so that the issues associated with the use of conventional room temperature ionic liquid-based electrolytes can be tackled. To fulfil this objective, a series of geminal di-cationic Organic Ionic Crystals (OICs), based on C3-, C6-, C8- and C9-alkylbridged bis-(methylpyrrolidinium)bromide are synthesized, and the structural features, thermal properties and phase behaviours of these as synthesized OICs have been investigated. Additionally, a number of electro-analytical techniques have been employed to assess their suitability as an efficient electrolyte composite (OIC:I2:TBAI) for all solid-state dye sensitised solar cells (DSSCs). The structural analysis has revealed that along with excellent thermal stability and well-defined surface morphology, all thsese OICs exhibit a well-ordered three-dimensional network of cations and anions that can serve as a conducting channel for the diffusion of iodide ions. Electrochemical investigations have shown that OICs with an intermediate length of alkyl bridge (C6- and C8-alkyl bridged) show better electrolytic performance than those that are based on OICs with a relatively shorter (C3-) or longer (C9-) alkyl-bridge chain. A careful analysis of the above data has essentially demonstrated that the length of the alkyl bridge chain plays a significant role in determining the structural organisation, morphology and eventually the ionic conductivity of OICs. Overall, the comprehensive knowledge on OICs that has been extracted from the current study is expected to be helpful to explore further new types of OIC-based all solid-state electrolytes with improved electrolytic performance for targeted applications.
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Affiliation(s)
- Amita Mahapatra
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Jatani, Khurda, Bhubaneswar 752050, Odisha, India.
- An OCC of Homi Bhabha National Institute (HBNI), Mumbai 400094, India
- Centre for Interdisciplinary Sciences (CIS), NISER, Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Aneeya K Samantara
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Jatani, Khurda, Bhubaneswar 752050, Odisha, India.
- An OCC of Homi Bhabha National Institute (HBNI), Mumbai 400094, India
- Centre for Interdisciplinary Sciences (CIS), NISER, Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Sahadev Barik
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Jatani, Khurda, Bhubaneswar 752050, Odisha, India.
- An OCC of Homi Bhabha National Institute (HBNI), Mumbai 400094, India
- Centre for Interdisciplinary Sciences (CIS), NISER, Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Malaya K Sahoo
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Jatani, Khurda, Bhubaneswar 752050, Odisha, India.
- An OCC of Homi Bhabha National Institute (HBNI), Mumbai 400094, India
- Centre for Interdisciplinary Sciences (CIS), NISER, Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - J N Behera
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Jatani, Khurda, Bhubaneswar 752050, Odisha, India.
- An OCC of Homi Bhabha National Institute (HBNI), Mumbai 400094, India
- Centre for Interdisciplinary Sciences (CIS), NISER, Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Moloy Sarkar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Jatani, Khurda, Bhubaneswar 752050, Odisha, India.
- An OCC of Homi Bhabha National Institute (HBNI), Mumbai 400094, India
- Centre for Interdisciplinary Sciences (CIS), NISER, Jatni, Khurda, Bhubaneswar 752050, Odisha, India
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