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Laws K, Buckingham MA, Aldous L. Self-assembled monolayers for electrostatic electrocatalysis and enhanced electrode stability in thermogalvanic cells. Chem Sci 2024; 15:6958-6964. [PMID: 38725507 PMCID: PMC11077577 DOI: 10.1039/d3sc06766a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 04/02/2024] [Indexed: 05/12/2024] Open
Abstract
Waste heat is ubiquitous; as such, sustainable and long-lasting devices are required to convert it into more useful forms of energy that can make use of this abundant potential resource. Thermogalvanic cells (or thermocells) can use the thermoelectrochemical properties of redox couples to achieve this; entropy-driven redox reactions allow them to act as liquid thermoelectrics. However, excellent electrocatalysis at the electrode surface is required for optimum conversion efficiency. Serendipitous observation of Nafion-based electrocatalysis prompted the exploration of electrostatically charged self-assembled monolayers (SAMs) inside a thermocell. Both electrostatic electrocatalysis and improved electrode stability were observed; in an aqueous K3[Fe(CN)6]/K4[Fe(CN)6]-based cell, modification with (3-trimethylammonium bromide)thiopropane resulted in higher electrical power, and protection against [Fe(CN)6]3-/4--induced gold passivation, relative to bare gold. Molecular-based electrostatic electrocatalysis could be an alternative to precious metal-based nanomaterial electrocatalysis, and could be integrated with (nano)carbon-based electrodes to further enhance the ability of thermogalvanic and other electrochemical energy conversion devices, e.g. redox flow batteries.
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Affiliation(s)
- Kristine Laws
- Department of Chemistry, Britannia House, King's College London London SE1 1DB UK
| | - Mark A Buckingham
- Department of Chemistry, Britannia House, King's College London London SE1 1DB UK
| | - Leigh Aldous
- Department of Chemistry, Britannia House, King's College London London SE1 1DB UK
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2
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Laws K, Buckingham MA, Farleigh M, Ma M, Aldous L. High Seebeck coefficient thermogalvanic cells via the solvent-sensitive charge additivity of cobalt 1,8-diaminosarcophagine. Chem Commun (Camb) 2023; 59:2323-2326. [PMID: 36752070 DOI: 10.1039/d2cc05413b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Thermogalvanic devices can chemically convert low grade (<200 °C) waste thermal energy into electrical energy. A temperature gradient across the device drives an entropically favourable electrochemical redox reaction, resulting in continuous current production. The voltage correlates with the entropy change during the redox reaction, which favours high valence metal complexes with high charge densities. Here we investigate cobalt (II/III) sarcophagine ([Co(SAR)]2+/3+) for application in thermogalvanic cells, as a function of solvent; the two uncoordinated amine groups 1,8-diaminosarcophagine are typically protonated to form tetracationic/pentacationic [Co(SARH2)]4+/5+. In water, [Co(SARH2)]4+/5+ gave a thermogalvanic Seebeck coefficient (Se) of +0.43 mV K-1, which is entropically consistent with just the Co2+/3+ core valence, whereas DMSO and ionic liquid solvents gave Se values of +1.84 and +2.04 mV K-1, respectively, in line with the 'Co4+/5+' overall complex. This work proves how the ionic charge on pendant moieties can undergo charge-additivity with the metal core to significantly boost entropically-driven processes, but only in suitably low dielectric and bulky solvents.
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Affiliation(s)
- Kristine Laws
- Department of Chemistry, King's College London, London, SE1 1DB, UK.
| | - Mark A Buckingham
- Department of Chemistry, King's College London, London, SE1 1DB, UK.
| | - Matthew Farleigh
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, SE1 7EH, UK
| | - Michelle Ma
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, SE1 7EH, UK
| | - Leigh Aldous
- Department of Chemistry, King's College London, London, SE1 1DB, UK.
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3
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Zhou H, Inoue H, Ujita M, Yamada T. Advancement of Electrochemical Thermoelectric Conversion with Molecular Technology. Angew Chem Int Ed Engl 2023; 62:e202213449. [PMID: 36239979 DOI: 10.1002/anie.202213449] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Indexed: 11/24/2022]
Abstract
Thermocells are a thermoelectric conversion technology that utilizes the shift in an electrochemical equilibrium arising from a temperature difference. This technology has a long history; however, its low conversion efficiency impedes its practical usage. Recently, an increasing number of reports have shown drastic improvements in thermoelectric conversion efficiency, and thermocells could arguably represent an alternative to solid thermoelectric devices. In this Minireview, we regard thermocells as molecular systems consisting of successive molecular processes responding to a temperature change to achieve energy generation. Various molecular technologies have been applied to thermocells in recent years, and could stimulate diverse research fields, including supramolecular chemistry, physical chemistry, electrochemistry, and solid-state ionics. These research approaches will also provide novel methods for achieving a sustainable society in the future.
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Affiliation(s)
- Hongyao Zhou
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hirotaka Inoue
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Mizuha Ujita
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Teppei Yamada
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
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Bodin C, Gelinas B, Deng J, Pithaksinsakul K, Zhu Y, Rochefort D, Fontaine O. Describing the unsuspected advantage of redox ionic liquids applied to electrochemical energy storage. Curr Opin Colloid Interface Sci 2023. [DOI: 10.1016/j.cocis.2023.101677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Aidoudi FH, Sinopoli A, Arunachalam M, Merzougui B, Aïssa B. Synthesis and Characterization of a Novel Hydroquinone Sulfonate-Based Redox Active Ionic Liquid. MATERIALS 2021; 14:ma14123259. [PMID: 34204769 PMCID: PMC8231554 DOI: 10.3390/ma14123259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 11/22/2022]
Abstract
Introducing redox-active moieties into an ionic liquid (IL) structure is an exciting and attractive approach that has received increasing interest over recent years for a various range of energy applications. The so-called redox-active ionic liquids (RAILs) provide a highly versatile platform to potentially create multifunctional electroactive materials. Ionic liquids are molten salts consisting of ionic species, often having a melting point lower than 100 °C. Such liquids are obtained by combining a bulky asymmetric organic cation and a small anion. Here, we report on the synthesis of a novel RAIL, namely 1-butyl-3-methylimidazolium hydroquinone sulfonate ((BMIM)(HQS)). (BMIM)(HQS) was synthesized in a two-step procedure, starting by the quaternization of methylimidazole using butylchloride to produce 1-butyl-3-methylimidazolium chloride ((BMIM)(Cl)), and followed by the anion exchange reaction, where the chloride anion is exchanged with hydroquinone sulfonate. The resulting product was characterized by 1H NMR, 13C NMR, FT-IR spectroscopy, themogravimetric analysis, and differential scanning calorimetry, and shows a high stability up to 340 °C. Its electrochemical behavior was investigated using cyclic voltammetry at different temperatures and its viscosity analysis was also performed at variable temperatures. The electrochemical response of the presented RAIL was found to be temperature dependent and diffusion controlled. Overall, our results demonstrated that (BMIM)(mix of HQS and HSQ) is redox active and possesses high stability and low volatility, leading to the employment of this RAIL without any additional supporting electrolyte or additives.
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Matsubara Y. Solvent Effect on Ferrocenium/Ferrocene Redox Couple as an Internal Standard in Acetonitrile and a Room-temperature Ionic Liquid. CHEM LETT 2020. [DOI: 10.1246/cl.190722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yasuo Matsubara
- Department of Material and Life Chemistry, Kanagawa University, Rokkakubashi, Yokohama, Kanagawa 221-8686, Japan
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Ikeda Y, Fukui K, Murakami Y. Integration of thermo-electrochemical conversion into forced convection cooling. Phys Chem Chem Phys 2019; 21:25838-25848. [PMID: 31729518 DOI: 10.1039/c9cp05028k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Forced convection cooling is important in numerous technologies ranging from microprocessors in data centers to turbines and engines, and active cooling is essential in these situations. However, active transfer of heat or thermal energy under a large temperature difference promptly destroys the exergy, which is the free-energy component of the thermal energy. In this study, to partially recover presently lost exergy in such situations, thermo-electrochemical conversion is integrated into forced convection cooling. We design and fabricate a test cell in which an electrolyte liquid is forced through a channel formed between two parallel electrodes and the hot-side electrode simulates an object to be cooled. Our experimental investigations show that the narrower interelectrode channels afford higher cooling and power generation performances. The mass transfer resistance is the most dominant type of resistance for all the conditions tested and the charge transfer kinetics is found to be controlled by the electrolyte viscosity. The dependence of the generated power on the flow rate is caused by the change in the diffusion coefficient of redox species with temperature. As an evaluation measure for such forced-flow thermo-electrochemical cells, the gain (Λ)-defined as the ratio of the generated power to the hydrodynamic pumping work required to force the liquid through the cell-is introduced. Λ is above unity in a certain flow rate region. This demonstrates that such a system can generate more electric power than the hydrodynamic pump work required to drive the liquid through the cell.
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Affiliation(s)
- Yutaka Ikeda
- School of Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
| | - Kazuki Fukui
- School of Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
| | - Yoichi Murakami
- School of Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
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Megat Hasnan MMI, Mohd Said S, Mohd Sabri MF, Mat Hussin SA, Abdullah N, Nik Ibrahim NMJ, Miyazaki Y, Mohd Salleh MF, Mohd Shah N. Optimised thermally driven molecular stability of an SCO metal complex for TEC Seebeck generation enhancement. RSC Adv 2019; 9:10626-10634. [PMID: 35515272 PMCID: PMC9062524 DOI: 10.1039/c9ra00779b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 03/20/2019] [Indexed: 01/02/2023] Open
Abstract
The thermoelectricity effect allows the generation of electrical potential in an electrolyte upon application of a thermal gradient. In the previous work, the spin crossover effect in metal complexes was shown to be beneficial for generating a high Seebeck coefficient due to the high entropy associated with the conformational change accompanying the spin state change. In this study, we examine the diamagnetic stability of a spin crossover material through optimisation of the ligand chain length. We show that the diamagnetic stability of the spin crossover material can enhance the thermoelectrochemical Seebeck effect through ligand optimisation of the octahedral structure. The increase of carbon chain length from C14 to C16 in the long alkyl chain of the N-donor ligand increased Seebeck generation in a Co(iii)L16 complex to 1.94-fold that of a previously studied paramagnetic Co complex, and in a Fe(iii)L16 complex to 3.43-fold that of a less diamagnetic Fe complex. We show with DSC studies of an Fe based octahedral complex that an endothermic absorption accompanies the spin crossover transition, which enhances the Seebeck coefficient of this metal complex. Thus, we can correlate the diamagnetic stabilisation with temperature. We therefore indicate a molecular design strategy for optimisation of a spin crossover metal complex. Highly stable reversible spin crossover electrolyte transition of Fe2+ to Fe3+ for high Seebeck generation.![]()
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Affiliation(s)
| | - Suhana Mohd Said
- Electrical Engineering Department, Engineering Faculty, Universiti Malaya 50603 Kuala Lumpur Malaysia
| | - Mohd Faizul Mohd Sabri
- Mechanical Engineering Department, Engineering Faculty, Universiti Malaya 50603 Kuala Lumpur Malaysia
| | - Siti Amira Mat Hussin
- Chemistry Department, Science Faculty, Universiti Malaya 50603 Kuala Lumpur Malaysia
| | - Norbani Abdullah
- Chemistry Department, Science Faculty, Universiti Malaya 50603 Kuala Lumpur Malaysia
| | | | - Yuzuru Miyazaki
- Department of Applied Physic, Graduate School of Engineering, Tohoku University 6-6-04, Aramaki Aza Aoba Aoba-ku Sendai Miyagi 980-8579 Japan
| | - Mohd Faiz Mohd Salleh
- Electrical Engineering Department, Engineering Faculty, Universiti Malaya 50603 Kuala Lumpur Malaysia
| | - Noraisyah Mohd Shah
- Electrical Engineering Department, Engineering Faculty, Universiti Malaya 50603 Kuala Lumpur Malaysia
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Thermoelectricity and Thermodiffusion in Magnetic Nanofluids: Entropic Analysis. ENTROPY 2018; 20:e20060405. [PMID: 33265495 PMCID: PMC7512924 DOI: 10.3390/e20060405] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 05/04/2018] [Accepted: 05/16/2018] [Indexed: 11/17/2022]
Abstract
An analytical model describing the thermoelectric potential production in magnetic nanofluids (dispersions of magnetic and charged colloidal particles in liquid media) is presented. The two major entropy sources, the thermogalvanic and thermodiffusion processes are considered. The thermodiffusion term is described in terms of three physical parameters; the diffusion coefficient, the Eastman entropy of transfer and the electrophoretic charge number of colloidal particles, which all depend on the particle concentration and the applied magnetic field strength and direction. The results are combined with well-known formulation of thermoelectric potential in thermogalvanic cells and compared to the recent observation of Seebeck coefficient enhancement/diminution in magnetic nanofluids in polar media.
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Black JJ, Dolan A, Harper JB, Aldous L. Kamlet–Taft solvent parameters, NMR spectroscopic analysis and thermoelectrochemistry of lithium–glyme solvate ionic liquids and their dilute solutions. Phys Chem Chem Phys 2018; 20:16558-16567. [DOI: 10.1039/c8cp02527d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
NMR, thermoelectrochemical and Kamlet–Taft solvochromatic analyses provide insight into the coordination of lithium in both dilute and concentrated lithium–glyme solutions.
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Affiliation(s)
| | - Andrew Dolan
- School of Chemistry
- UNSW Australia
- Sydney
- Australia
| | | | - Leigh Aldous
- School of Chemistry
- UNSW Australia
- Sydney
- Australia
- Department of Chemistry
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