Classifying Electrolyte Solutions by Comparing Charge and Mass Transport
Berhard Roling
Vendredi 10 Fevrier 2023 à 11h (salle 32-42.101)
Abstract
Electrolyte solutions play an important role in many scientific fields, such as electrochemistry, energy research, chemical synthesis, biochemistry and pharmaceutical research [1-4]. The conventional classification of electrolyte solutions as “strong” or “weak” accounts for their charge transport properties, but neglects their mass transport properties, and is not readily applicable to highly concentrated solutions.
Here we use the Onsager transport formalism in combination with linear response theory to attain a more general classification, which is based on a comparison of charge and mass transport [5, 6]. Charge transport is characterized by the ionic conductivity σ??? and mass transport by the neutral salt transport coefficient σ????. Three classes of electrolyte solutions are then distinguished [5,6]: (i) “Strong electrolytes” with σ???≈σ????; (ii) “weak charge transport electrolytes” with σ???≪σ????; and (iii) “weak mass transport electrolytes” with σ????≪σ???. While classes (i) and (ii) encompass the classical “strong” and “weak” electrolytes, respectively, many highly concentrated electrolytes fall into class (iii) and thus exhibit transport properties clearly distinct from classical strong and weak electrolytes.
References:
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[2] Z. Zhang, J. Song, and B. Han, Chem. Rev. 2017, 117, 6834.
[3] M. Watanabe, M. L. Thomas, S. Zhang, K. Ueno, T. Yasuda, K. Dokko, Chem. Rev. 2017, 117, 7190.
[4] M. Li, C. Wang, Z. Chen, K. Xu, J. Lu, Chem. Rev. 2020, 120, 6783.
[5] B. Roling, J. Kettner, V. Miß, Energy Environ. Mater. 2022, 5, 6.
[6] B. Roling, V. Miß, J. Kettner, Energy Environ. Mater. 2022, e12533.
doi: 10.1002/eem.12553
