Abstract: Synchrotron-based X-rays are a powerful characterization tool that can probe across many relevant length scales (from atomistic to millimeter) with different techniques that are sensitive to distinct features such as microstructure, chemistry, and morphology. Because of the high flux available and penetrating power of synchrotron-based X-rays, batteries can be probed under realistic (operando) conditions, which enables us to understand and overcome failure mechanisms of the next generation of battery materials. At the Stanford Synchrotron Radiation Lightsource at SLAC National Accelerator Laboratory, we have a suite of advanced X-ray characterization tools and have enabled a robust means of multimodal, operando characterization using a standard pouch cell geometry. With transmission X-ray microscopy (TXM), we capture morphology changes on either the cathode or anode during battery operation. Combined with absorption spectroscopy, the TXM provides maps of the local state of charge of active material particles. With high speed X-ray diffraction and X-ray absorption spectroscopy, we track the changes in crystallographic phases, local coordination, and chemistry. Results from all of these techniques can be combined together to get a more complete picture of the key degradation pathways of active battery materials to develop mitigation strategies for longer lasting energy storage.

Bio: Johanna Nelson Weker is a lead scientist at SLAC National Accelerator Laboratory and the group lead for Hard X-ray Materials Science at Stanford Synchrotron Radiation Lightsource (SSRL). She also holds an adjunct professorship position in the Materials Science and Engineering Department at Stanford University. Her research focuses on synchrotron-based X-ray characterization of materials and systems far from equilibrium. Her work spans a range of topics including electrochemical energy storage, catalysis, and additive manufacturing. Dr. Nelson Weker received a Ph.D. in physics from Stony Brook University in 2010.

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