Operando Probing and Adjusting of the Electrode Process of Multivalent Metals at Extreme Temperature

What is it about?

Nearly half of the elements in the periodic table are extracted, refined, or plated using electrodeposition in high-temperature melts. However, operando observations and tuning of the electrodeposition process during realistic electrolysis operations are extremely difficult due to severe reaction conditions and complicated electrolytic cell, which makes the improvement of the process very blind and inefficient. Here, we developed a multipurpose operando high-temperature electrochemical instrument that combines operando Raman microspectroscopy analysis, optical microscopy imaging, and a tunable magnetic field. Subsequently, the electrodeposition of Ti—which is a typical polyvalent metal and generally shows a very complex electrode process—was used to verify the stability of the instrument. The complex multistep cathodic process of Ti in the molten salt at 823 K was systematically analyzed by a multidimensional operando analysis strategy involving multiple experimental studies, theoretical calculations, etc. The regulatory effect and its corresponding scale-span mechanism of the magnetic field on the electrodeposition process of Ti were also elucidated, which would be inaccessible with existing experimental techniques and is significant for the real-time and rational optimization of the process. Overall, this work established a powerful and universal methodology for in-depth analysis of high-temperature electrochemistry.

Featured Image

Photo by Timo Volz on Unsplash

Photo by Timo Volz on Unsplash

Why is it important?

High-temperature electrochemistry has significant advantages and many applications in a variety of areas (metallurgy, energy, etc.), not only benefiting from the high-temperature characteristic, which can lower the “threshold” of the reaction thermodynamically and increase the reaction rate kinetically, but also arising from the broad employing of inexpensive inorganic salt electrolyte. However, the in-situ and in-depth analysis on HTE is very difficult due to the high temperature itself, strong corrosion, and a complicated reaction cell. Here, we developed a multidimensional instrument that can monitor and adjust the electrode process in a high-temperature and complex operating condition, which will promote the deep understanding on HTE and lay the foundation for real-time and rational process optimization.