Inside the Laboratory: The Weker Group at SLAC National Accelerator Laboratory

"Inside the Laboratory" is a joint series with LCGC and Spectroscopy profiling analytical scientists and their research groups at universities worldwide. This series spotlights the current chromatographic and spectroscopic research their groups are conducting and the importance of their research in analytical chemistry and specific industries. In this edition of “Inside the Laboratory,” Johanna Nelson Weker of SLAC National Accelerator Laboratory discusses her laboratory’s work in battery analysis (1,2).

Will Wetzel: Your lab uses synchrotron-based X-ray tools to observe complex, dynamic systems in operando. Can you explain how these tools help uncover failure mechanisms in materials like batteries or electrolyzers?

Johanna Nelson Weker: We use all the different tools that we have. Namely, they're in three categories. Spectroscopy, scattering, and imaging. The spectroscopy tools that we have allow us to look at the chemistry of materials and how the chemistry is changing.

You can also look at the local structure of materials with spectroscopy, even if that local structure isn't crystalline. So, you can look at amorphous materials or materials and liquids. Scattering techniques allow you to look at crystalline structures, for the most part. They always tell you about ordering. So, you can use them to look at how the crystal structure is changing over time. You can also look at local ordering. It's a very complementary technique to some of the spectroscopy we do. And then finally, imaging. We can do that on many different length scales.

We can go up to large length scales of looking at materials that are centimeters in size, and looking at a length scale, a resolution essentially of 50–100 microns. But we can also go very deep and small and go into length scales that are fields of view that are more like tens of microns with resolutions that are in the nanometers, tens of nanometers.

The nice thing about imaging that we can also do is combine imaging with spectroscopy or imaging with diffraction. And so, we can take a small X-ray probe and scan across the sample, and instead of collecting just an intensity at each spot, we can collect a spectrum, or we can collect a diffraction pattern.

And so, it gives us a lot of flexibility. We can look at the average structure of what's going on, what's the crystal change, what's the chemistry changes, and what's the local changes? But we can also get the heterogeneity across samples.

You can watch Part 1 of our interview with Weker below:

This interview segment is part 1 of a four-part interview with Weker.

References

1. SLAC – National Accelerator Laboratory, About Us. Stanford.edu. Available at: https://www6.slac.stanford.edu/about/our-story (accessed 2025-04-25).
2. SLAC – Stanford Battery Center, Johanna Weker. SLAC.Stanford.edu. Available at: https://batterycenter.slac.stanford.edu/person/johanna-weker (accessed 2025-04-25).