Operando Studies of the Evolution of Electrode Inhomogeneities and of Solid Electrolyte Interphase Formation Using Spatial Frequency Heterodyne X-ray Imaging

Stephan, Alexandra Katarina

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Year:: 2019
Contributor:: Stephan, Alexandra Katarina (creator); Rose-Petruck, Christoph (Advisor); Sheldon, Brian (Reader); Rubenstein, Brenda (Reader); Brown University. Department of Chemistry (sponsor)
Genre:: theses
Subject:: Li-ion Batteries; batteries; Lithium ion batteries; X-ray; X-ray imaging
Extent:: xvi, 163 p.
DOI: https://doi.org/10.26300/tje0-x424

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Abstract:: Improvements to lithium-ion battery performance have been hampered by the lack of operando imaging techniques to study electrodes changes in unmodified batteries. In this work, lithium-ion cells are imaged using operando Spatial Frequency Heterodyne X-ray Imaging (SFHXI). SFHXI is a nondestructive, non-synchrotron-based X-ray imaging technique that simultaneously measures the amount of X-rays scattered at hundreds of thousands of points. It is sensitive to the electron density and volume changes that silicon composite electrodes undergo during cycling. Entire cells are imaged during short exposures, allowing for operando quantification of the inhomogeneities that develop during cycling. The lithiation and delithiation of the Si nanoparticles as well as solid electrolyte formation are tracked by the scatter intensity measured by SFHXI. Whether a cell will be high or low capacity can be determined based solely off scatter intensity behavior during the first lithiation. Scatter intensity tracks the thickness of solid electrolyte interphase. The homogeneity of the lithiation and delithiation of Si nanoparticles and of solid electrolyte formation was quantified. Although the solid electrolyte interphase forms relatively uniformly across the electrode, this is not sufficient to result in the uniform lithiation of the silicon. These novel insights into operating lithium-ion cells provided by SFHXI contribute to a better understanding of the complex electrochemical processes and material changes that electrodes undergo during cycling and can subsequently lead to the development of high performance and safe batteries.
Notes:: Thesis (Ph. D.)--Brown University, 2019

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Rights: In Copyright
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Stephan, Alexandra Katarina, "Operando Studies of the Evolution of Electrode Inhomogeneities and of Solid Electrolyte Interphase Formation Using Spatial Frequency Heterodyne X-ray Imaging" (2019). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.26300/tje0-x424

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Chemistry Theses and Dissertations

Theses and Dissertations for the Chemistry department.
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