Water, Not Salt, Causes Most of the Seebeck Effect of Nonisothermal Aqueous Electrolytes

A temperature difference between two electrolyte-immersed electrodes often yields a voltage Δψ between them. This electrolyte Seebeck effect is usually explained by cations and anions flowing differently in thermal gradients. However, using molecular simulations, we found almost the same Δψ for cell...

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Bibliographic Details
Published in:Physical review letters 2024-05, Vol.132 (18), p.186201-186201, Article 186201
Main Authors: Nickel, Ole, Ahrens-Iwers, Ludwig J V, Meißner, Robert H, Janssen, Mathijs
Format: Article
Language:English
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Summary:A temperature difference between two electrolyte-immersed electrodes often yields a voltage Δψ between them. This electrolyte Seebeck effect is usually explained by cations and anions flowing differently in thermal gradients. However, using molecular simulations, we found almost the same Δψ for cells filled with pure water as with aqueous alkali halides. Water layering and orientation near polarizable electrodes cause a large temperature-dependent potential drop χ there. The difference in χ of hot and cold electrodes captures most of the thermovoltage, Δψ≈χ_{hot}-χ_{cold}.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.132.186201