A 4D x-ray computer microtomography for high-temperature electrochemistry

Abstract

High-temperature electrochemistry is widely used in many fields. However, real-time observations and an in-depth understanding of the inside evolution of this system from an experimental perspective remain limited because of harsh reaction conditions and multiphysics fields. Here, we tackled this challenge with a high-temperature electrolysis facility developed in-house. This facility permits in situ x-ray computer microtomography (μ-CT) for nondestructive and quantitative three-dimensional (3D) imaging. In an electrorefining system, the μ-CT probed the dynamic evolution of 3D morphology and components of electrodes (4D). Subsequently, this 4D process was visually presented via reconstructed images. The results monitor the efficiency of the process, explore the dynamic mechanisms, and even offer real-time optimization. This 4D analysis platform is notable for in-depth combinations of traditional electrochemistry with digital twin technologies owing to its multiscale visualization and high efficiency of data extraction.

Upcycling of Titanium by Molten Salt Electrorefining

“…For comparison, the curvature visualization results in the titanium anode are presented at different electrolysis stages. The curvature nicely shows that the local roughness and the zone with high roughness is commonly regarded as an active zone where the dissolution occurs more easily . The comparison results, especially those in Figure b,d, suggest that the congruent relationship between the roughness and the dissolution thickness is not as solid as we thought.…”

“…The electrorefining experiment was conducted in a homemade high-temperature electrochemical instrument that permits in situ X-ray computer tomography (CT) for quantitative 3D imaging of the electrodes. 27 With the help of this device, we can in situ and non-destructively monitor the dynamic behavior of the dissolution of the anode and the deposition of titanium at the cathode.…”

“…To close to the real electrorefining process of titanium, the anode with irregularly shaped apertures and the surface was prepared by compressing titanium sponge granules in this work. The electrorefining experiment was conducted in a homemade high-temperature electrochemical instrument that permits in situ X-ray computer tomography (CT) for quantitative 3D imaging of the electrodes . With the help of this device, we can in situ and non-destructively monitor the dynamic behavior of the dissolution of the anode and the deposition of titanium at the cathode.…”

“…The in situ 3D imaging instrument of the high-temperature electrolytic cell was fixed vertically to the X-ray system, and for more detail on this instrument, please see our previous work. 27 The scan of electrodes before electrolysis and during electrolysis was conducted by rotating the cell under high-temperature operating conditions. The 3D results were obtained in 1200−2000 cross-sectional slices.…”

Dynamic evolution of high-temperature molten salt electrolysis of titanium under different operational conditions

“…18 Moreover, we successfully combined in situ analysis by X-ray computer microtomography with high-temperature molten salt electrolysis and preliminarily verified the feasibility of the in situ analysis of the electrochemical process, which lays the groundwork for this study. 19,20 The electrochemical reactions in this work were carried out in crucibles by X-ray computer microtomography. This enables real-time capture of 3D images of electrode reactions under extreme reaction conditions, such as the processes of cathodic deposition and anodic dissolution.…”