Work

High-speed in situ observation of transient bubble dynamics during molten salt electrolysis using laser Shadowgraphy

Year: 2026

Type: article

Abstract: High-speed in situ observation of transient product evolution during high-temperature molten-salt electrolysis is essential for understanding and controlling electrochemical materials processing. However, the observation with sufficient temporal resolution remains limited by thermal radiation, optical distortion, and corrosive environments. In this research, we developed a high-speed laser shadowgraph system enabling short-exposure imaging of both electrode regions during electrolysis in molten LiCl–KCl at 723 K. Imaging with a temporal resolution of 0.0005 s simultaneously resolved anodic bubble evolution and a metal-fog region near the cathode. The anodic bubbles underwent recurrent growth, coalescence, collective detachment, transient clearing of the visible electrode surface, and regeneration. Quantification of the projected bubble area fraction revealed gradual accumulation followed by abrupt decreases associated with collective detachment, demonstrating pulsatile gas release under steady current. Moreover, detached large bubbles deformed the metal-fog boundary, indicating hydrodynamic coupling between products at opposing electrodes. The high-speed in situ observation system reveals transient product-formation and transport dynamics inaccessible to time-averaged measurements.

Source: Electrochemistry Communications

DOI: 10.1016/j.elecom.2026.108263