A novel pressurized operando battery cell for laboratory X-ray computed tomography

Abstract Battery research relies on microscopy techniques for their microstructure characterizations and operando mechanism investigations. Such techniques include scanning electron microscopy (SEM) or X-ray computed tomography (XCT). The latter one plays a special role due to its ability to visualize a sample or even a whole cell completely in three dimensions. Additionally, imaging is conducted without destructing the investigated sample enabling the possibility of operando measurements. Therefore, XCT advances to a highly valuable method for investigating battery components and interfaces in the pristine, intermediate and post-mortem state or while operating the battery. Despite the evident advantages, XCT of certain battery types such as lithium metal are challenging due to the combination of low and high attenuating materials and air sensitive elements. This work presents the development of a pressurized operando battery cell for laboratory X-ray computed tomography. The developed cell makes the investigation of air sensitive and for XCT challenging battery systems possible. It is resistant to various chemicals and air-tight, thus suitable for different battery types. A dynamic sealing via a metal bellow allows to set and change the stack pressure during operation and after assembly, respectively. The design is optimized for maintaining a high photon flux without neglecting a reliable long-term sealing and practical handling. Initial measurements of a symmetric lithium metal cell with hybrid solid electrolyte demonstrate the capabilities of the developed cell holder.