Precious metal oxygen-evolving anodes for electrolytic reduction of metal oxides in molten LiCl-Li2O electrolyte

Khan, Md Ikram; Asghari-Rad, Peyman; Baldivieso, Stephanie Castro; Moudgal, Aditya; Tripathy, Prabhat K.; Herrmann, Steven D.; Chidambaram, Dev; Kim, Hojong

doi:10.1016/j.jelechem.2026.119798

Precious metal oxygen-evolving anodes for electrolytic reduction of metal oxides in molten LiCl-Li₂O electrolyte

Journal Article · Mon Jan 05 00:00:00 EST 2026 · Journal of Electroanalytical Chemistry

DOI:https://doi.org/10.1016/j.jelechem.2026.119798· OSTI ID:3021263

Khan, Md Ikram ^[1]; Asghari-Rad, Peyman ^[1]; ^[2]; Moudgal, Aditya ^[3]; ^[3]; ^[3]; Chidambaram, Dev ^[4]; Kim, Hojong ^[1]

Pennsylvania State Univ., University Park, PA (United States)
Pennsylvania State Univ., University Park, PA (United States); Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Univ. of Nevada, Reno, NV (United States)

Understanding the electrochemical stability of oxygen-evolving anode materials in molten salt electrolytes is essential to enable decarbonized electrolytic reduction of metal oxides (e.g., used nuclear oxide fuels). Here, this work investigated three precious metals (Ir, Ru, and Pt) as oxygen-evolving anodes in molten LiCl-Li₂O (99.0-1.0 wt%) at 650 °C. For consistent measurements, this work employed a three-electrode cell comprised of a two-phase Li-Bi (65-35 at%) reference electrode and a NiO counter electrode. Anodic polarization behavior of each anode was investigated via cyclic voltammetry (CV) and chronoamperometry. The onset potential for oxygen evolution was observed at E > 2.9 V (vs. Li/Li⁺) for the Ir and Ru anodes and anodic current density was as high as 1.0 A cm^-2 at 3.23 V. The dimensional stability of each anode was evaluated from long-term electrolysis experiments (10.0-32.1 h) at 3.23 V. Rapid consumption of the Pt anode was observed after the application of 26,453 C cm^-2 with a reduction in diameter of about 15.8% due to the formation of a non-protective Li₂PtO₃ compound. The formation of this compound was also observed during CV measurements as additional anodic waves at potentials more negative than that of oxygen evolution. In contrast, both the Ir and Ru anodes exhibited excellent dimensional stability with a reduction in diameter or thickness of less than 1.5% even after applying greater charge density of ~41,100 C cm^-2, demonstrating superior stability during oxygen evolution in the LiCl-Li₂O electrolyte.

View Accepted Manuscript (DOE)

Research Organization:: Idaho National Laboratory (INL), Idaho Falls, ID (United States)

Sponsoring Organization:: USDOE Advanced Research Projects Agency - Energy (ARPA-E); USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Nuclear Energy (NE)

Grant/Contract Number:: AR0001697; AR0001900; EE0011213

OSTI ID:: 3021263

Report Number(s):: INL/JOU--25-87868

Journal Information:: Journal of Electroanalytical Chemistry, Journal Name: Journal of Electroanalytical Chemistry Vol. 1003; ISSN 1572-6657

Publisher:: ElsevierCopyright Statement

Country of Publication:: United States

Language:: English

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