Effects of Li2O on the thermodynamic properties of LiCl-UCl3 molten salt: A first-principles molecular dynamics study

doi:10.1016/j.cjche.2025.06.035

中国化学工程学报 ›› 2025, Vol. 88 ›› Issue (12): 133-141.DOI: 10.1016/j.cjche.2025.06.035

Effects of Li₂O on the thermodynamic properties of LiCl-UCl₃ molten salt: A first-principles molecular dynamics study

Wentao Zhou, Lve Lin, Yuan Yin, Jia Song, Xinyu Zhang, Yafei Wang

School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

收稿日期:2025-04-20 修回日期:2025-05-24 接受日期:2025-06-11 出版日期:2026-02-09 发布日期:2025-09-17
通讯作者: Yafei Wang,E-mail:itsme@sjtu.edu.cn
基金资助:
The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (22476130 and 12205190).

Effects of Li₂O on the thermodynamic properties of LiCl-UCl₃ molten salt: A first-principles molecular dynamics study

Wentao Zhou, Lve Lin, Yuan Yin, Jia Song, Xinyu Zhang, Yafei Wang

School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

Received:2025-04-20 Revised:2025-05-24 Accepted:2025-06-11 Online:2026-02-09 Published:2025-09-17
Contact: Yafei Wang,E-mail:itsme@sjtu.edu.cn
Supported by:
The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (22476130 and 12205190).

摘要/Abstract

摘要： Electrolytic reduction is a crucial process during the pyroprocessing of oxide spent fuel. This paper investigates the effects of different concentrations of Li₂O on the properties of the LiCl-UCl₃-Li₂O molten salt system during electrolytic reduction using first-principles molecular dynamics simulations. The study reveals that increasing Li₂O concentration lowers the ion diffusion coefficients of Li⁺, Cl^-, and O^2- in the electrolyte, which has negative effect on the transport property of the system. A thorough analysis of the ligand structures formed by various components in the molten salt was conducted, including radial distribution functions and angular distribution functions. The analysis reveals that oxygen ions compete with chloride ions for coordination with cations. This competitive interaction has a significant impact on the coordination between Li-Cl and U-Cl elements, thereby influencing the microstructure. The analysis of electronic structures shows that the addition of Li₂O affects the charge transfer among lithium, uranium, and chlorine, impacting the bond strength between anions and cations. Finally, the calculation of redox potential shows that an appropriate concentration of Li₂O is beneficial to the electrochemical reduction process. The research results provide a theoretical basis for the design of molten salts in the electrolytic reduction process.

关键词: First-principle, Molecular dynamics, LiCl-UCl₃-Li₂O, Electrolytic reduction

Abstract: Electrolytic reduction is a crucial process during the pyroprocessing of oxide spent fuel. This paper investigates the effects of different concentrations of Li₂O on the properties of the LiCl-UCl₃-Li₂O molten salt system during electrolytic reduction using first-principles molecular dynamics simulations. The study reveals that increasing Li₂O concentration lowers the ion diffusion coefficients of Li⁺, Cl^-, and O^2- in the electrolyte, which has negative effect on the transport property of the system. A thorough analysis of the ligand structures formed by various components in the molten salt was conducted, including radial distribution functions and angular distribution functions. The analysis reveals that oxygen ions compete with chloride ions for coordination with cations. This competitive interaction has a significant impact on the coordination between Li-Cl and U-Cl elements, thereby influencing the microstructure. The analysis of electronic structures shows that the addition of Li₂O affects the charge transfer among lithium, uranium, and chlorine, impacting the bond strength between anions and cations. Finally, the calculation of redox potential shows that an appropriate concentration of Li₂O is beneficial to the electrochemical reduction process. The research results provide a theoretical basis for the design of molten salts in the electrolytic reduction process.

Key words: First-principle, Molecular dynamics, LiCl-UCl₃-Li₂O, Electrolytic reduction

Wentao Zhou, Lve Lin, Yuan Yin, Jia Song, Xinyu Zhang, Yafei Wang. Effects of Li₂O on the thermodynamic properties of LiCl-UCl₃ molten salt: A first-principles molecular dynamics study[J]. 中国化学工程学报, 2025, 88(12): 133-141.

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Effects of Li₂O on the thermodynamic properties of LiCl-UCl₃ molten salt: A first-principles molecular dynamics study

Effects of Li₂O on the thermodynamic properties of LiCl-UCl₃ molten salt: A first-principles molecular dynamics study

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