Direct Conversion of Phase-Transition Entropy into Electrochemical Thermopower and the Peltier Effect
© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.
| Veröffentlicht in: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 35(2023), 36 vom: 14. Sept., Seite e2303341 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2023
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| Zugriff auf das übergeordnete Werk: | Advanced materials (Deerfield Beach, Fla.) |
| Schlagworte: | Journal Article NIPAM thermo-electrochemical cells thermocells thermoelectric conversion viologen |
| Zusammenfassung: | © 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH. A thermocell generates thermopower from a temperature difference (ΔT) between two electrodes. The converse process of thermocells is an electrochemical Peltier effect, which creates a ΔT on the electrodes by applying an external current. The Seebeck coefficient (Se ) of the electrochemical system is proportional to the entropy change of the redox reaction; therefore, a redox system having a significant entropy change is expected to increase the Se . In this study, a thermoresponsive polymer having a redox-active moiety, poly(N-isopropyl acrylamide-co-N-(2-acrylamide ethyl)-N'-n-propylviologen) (PNV), is used as the redox species of a thermocell. PNV2+ dication undergoes the coil-globule phase transition upon the reduction to PNV+ cation radical, and a large entropy change is introduced because water molecules are freed from the polymer chains. The Se of PNV thermocell drastically increased to +2.1 mV K-1 at the lower critical solution temperature (LCST) of PNV. The entropy change calculated from the increment of Se agrees with the value evaluated by differential scanning calorimetry. Moreover, the electrochemical Peltier effect is observed when the device temperature is increased above the LCST. This study shows that the large entropy change associated with the coil-globule phase transition can be used in electrochemical thermal management and refrigeration technologies |
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| Beschreibung: | Date Revised 07.09.2023 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.202303341 |