In Situ Lab- and Synchrotron-based X-ray Microscopy

X-ray tomography/microscopy allows for 3D, nondestructive imaging of air-sensitive materials used in modern energy devices. The first half of this seminar presents an in situ approach implemented on the ZEISS Xradia Versa laboratory system to observe morphological degradation of glass-ceramic Li3PS4 solid electrolytes during lithium plating. Experiments used a custom-built electrochemical cell to observe that under different lithium deposition rates, multiple different degradation modes are possible. Short circuiting via lithium dendrites occurs with the size of dendritic structures below the resolution of tomography images.

Part 2 of the seminar shifts to synchrotron-based hard X-ray transmission X-ray microscopy (TXM), an ideal tool for in situ and operando studies of next-generation battery operation and failure mechanisms. The high-energy X-rays provide relatively relaxed restrictions on in situ environments, enabling high-resolution 2D microscopy and tomography during battery cycling. The high photon flux of synchrotron-based TXM allows imaging at the sub-second timescale to capture the relevant dynamics during cycling. Moreover, by tuning the incident X-ray energy to specific absorption edges, TXM can capture elemental and chemical (spectromicroscopy) changes at 30 nm resolution within a few minutes. The speakers discuss the use of synchrotron-based TXM to track electrochemical and morphological changes in the electrode materials in real time during typical battery operation.

Key Learnings:

• Understand the signal observed from XCT in the context of lithium metal and solid electrolyte materials.
• Understand the relevant lengthscales involved in solid electrolyte mechanical degradation.
• See how the latest advances in synchrotron TXM are being applied for in operando and chemical imaging.