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 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≈χhot-χcold.

DDC Class

541.3: Physical Chemistry

530: Physics

Funding(s)

SFB 986: Teilprojekt C01 - Multiskalige photonische Materialien mit anpassbarer Absorption und thermischer Emission

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publishedVersion

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

PhysRevLett.132.186201.pdf

Type

Main Article

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2.11 MB

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Adobe PDF

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Water, not salt, causes most of the Seebeck effect of nonisothermal aqueous electrolytes