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DOE OSTI · 3385007

Direct Measurement of Cl − Activity in Metal Chloride Molten Salts using a Cl 2 /Cl − Electrode

Maltsev, Dmitry [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000156781465)·Halstenberg, Phillip W. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States)] (ORCID:0000000260304503)·Yuan, Yating [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:000900060632805X)·Kim, Ellie M. [University of Tennessee, Knoxville, TN (United States)] (ORCID:0000000349061261)·Mahurin, Shannon Mark [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000337921631)·Willit, James [Exodys Energy, New York, NY (United States)] (ORCID:0000000322186187)·Dai, Sheng [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States)] (ORCID:0000000280463931)
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Abstract

Molten metal chloride salts are promising candidates for advanced heat transfer fluids in generation IV nuclear reactors and beyond. The activity of the chloride ion in the salt has a large influence on the redox characteristics of the corresponding molten salt. There exists a knowledge gap for the direct measurement of chlorobasicity (Lewis basicity) in molten-salt mixtures. Here, the focus of this work was to develop a Cl 2 /Cl − electrode for the direct measurement of chloride activity in molten metal-chloride salt mixtures. The LiCl–KCl eutectic system was utilized as the reference melt to determine the change in chloride ion activity as increasing concentrations of MgCl 2 are added to the LiCl–KCl eutectic working electrode. The results of the measurements indicated a reduction in chloride ion activity as the concentration of magnesium chloride increased, consistent with the complexation of free chlorides by Lewis acidic magnesium cationic species. The Temkin model was used to estimate the thermodynamic properties of MgCl 4 2− complex.

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ChlorideChloride ActivityChlorineChlorobasicityElectrochemistryLewis AcidityMolten SaltReference Electrode

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Maltsev, Dmitry [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000156781465), Halstenberg, Phillip W. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States)] (ORCID:0000000260304503), Yuan, Yating [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:000900060632805X), Kim, Ellie M. [University of Tennessee, Knoxville, TN (United States)] (ORCID:0000000349061261), Mahurin, Shannon Mark [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000337921631), Willit, James [Exodys Energy, New York, NY (United States)] (ORCID:0000000322186187), Dai, Sheng [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States)] (ORCID:0000000280463931). 2026-01-27. Direct Measurement of Cl − Activity in Metal Chloride Molten Salts using a Cl 2 /Cl − Electrode. https://doi.org/10.1149/1945-7111/ae36fa

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