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DY: Fachverband Dynamik und Statistische Physik

DY 49: Statistical Physics: General

DY 49.7: Vortrag

Freitag, 9. September 2022, 11:15–11:30, H20

The reversible heat production during the electric double layer buildup: Analysis with an extension of the primitive model by hydration shells — •Philipp Pelagejcev, Fabian Glatzel, and Andreas Härtel — Albert-Ludwigs-Universität Freiburg

The reversible heat production during the electric double layer (EDL) buildup was measured experimentally [Janssen et al., Phys. Rev. Lett. 119, 166002 (2017)] and in theoretical work [Glatzel et al., J. Chem. Phys. 154, 064901 (2021)], it was found that steric interactions of ions with the flat electrodes, which result in the so-called Stern layer, are sufficient to explain the experimental results. In the latter only symmetric ion sizes in a restricted primitive model were examined.

In this work, I present the impact of ion asymmetry on the reversible heat production for each electrode separately. Additionally, an extension of the primitive model where hydration shells of ions can evade in the vicinity of the electrodes is discussed. With this extended model one can describe situations where one electrode is heated and the other electrode is cooled simultaneously during charging, while both electrodes together behave similarly to the already mentioned experimental results.

Thus, in experiments the heat production should be measured for each electrode separately. By this, the importance of certain ingredients for a primitive model based electrolyte could be evaluated experimentally, finally leading to a deeper understanding of EDLs. (Reference: [Pelagejcev et al., J. Chem. Phys. 156, 034901 (2022)])