ZOYC Online

Johanna Nelson Weker graduated in 2005 with a B.S. in mathematics and physics from Muhlenberg College, Allentown, PA. In 2010, she received a Ph.D. in physics from Stony Brook University, NY, where she studied coherent diffractive imaging (CDI) with X-rays, a microscopy technique that eliminates the need for X-rays lenses, which are both inefficient and difficult to fabricate. Much of her graduate research was performed at the Advanced Lightsource in Berkeley, CA. In 2010, she accepted a postdoctoral position at Stanford University working at the Stanford Synchrotron Lightsource at SLAC National Laboratory. With the move across the country, she transitioned to using X-rays to study energy storage materials such as Li-ion batteries under operating conditions. In 2013, she became an associate staff scientist in the Materials Science Division at SLAC, and in 2015, she became a staff scientist within the same division. In addition to a vibrant research group, she helps run the transmission X-ray microscopy on beamline 6-2 at SSRL.

Geoff McConohy is a Ph.D. candidate working under William Chueh at Stanford University. He studies the interfaces of solid electrolytes for application to high-energy-density batteries. He holds a B.S. in engineering physics from the University of Wisconsin-Madison and completed two internships at Sandia National Laboratories, Livermore, CA.

This live event is presented by Dr. Johanna Nelson & Geoff McConohy

In Situ Lab- and Synchrotron-based X-ray Microscopy Applied to Next-generation Battery Development

November 18, 2020 | 2:00 pm EST

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