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MSE Thesis Defense: “Cryogenic Microscopies of Energy Storage Materials: Insights into Metal Anodes, Solid-Electrolyte Interfaces, and Mxenes”

February 7 at 11:30 AM - 1:00 PM

The growing global energy demand has driven the development of advanced batteries, particularly lithium metal anodes and anode-free systems, due to their potential for higher energy density at reduced costs. However, characterizing the interfaces within these systems presents a critical challenge due to their susceptibility to decomposition during conventional atomic-resolution analysis. The emergence of Cryogenic Electron Microscopy (cryo-EM), recognized by the 2017 Nobel Prize in Chemistry, has revolutionized structural characterization by enabling near-atomic resolution imaging at liquid nitrogen temperatures. Originally transforming biomolecule imaging, this technique has now extended to materials science, making it ideal for investigating degradation-prone battery components and other sensitive materials while significantly reducing beam-induced damage.
In this work, we developed and implemented an integrated characterization approach combining multiple advanced techniques. Our methodology merges aberration-corrected (Scanning) Transmission Electron Microscopy ((S)TEM) with spectroscopic tools including
Energy-Dispersive X-ray Spectroscopy (EDS) and Electron Energy Loss Spectroscopy (EELS) for atomic-level structural and chemical analysis. For sample preparation and protection, we pioneered a novel approach combining Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) with cryogenic Focused Ion Beam (cryo-FIB), enabling robust detection and mapping of degradation-prone materials such as lithium hydride in battery anodes. Our systematic investigation revealed crucial insights into battery interfaces and materials. Using an integration of cryo-FIB-SEM, cryo-(S)TEM, EDS, and 4D-STEM, we uncovered the unique characteristics of solid-electrolyte interfaces (SEI) in sodium metal batteries with solid polymer electrolytes. The analysis revealed a distinctive thin SEI layer with reduced carbon content, resulting in favorable “round” sodium nucleation patterns that contrast with the dendritic formations typical in liquid electrolyte systems. We extended this approach to examine electron beam-induced defects in titanium carbides and carbonitrides MXenes, where our observations led to implementing cryo-STEM as a solution for preserving the pristine material structure and exam it as a potential current collector for the batteries.
This comprehensive study demonstrates the transformative potential of cryogenic electron microscopy techniques in advancing our understanding of sensitive battery materials and interfaces, thereby contributing to the development of next-generation energy storage solutions.

Yihui Zhang

PhD Candidate - Department of Materials Science and Engineering

Details

Date:
February 7
Time:
11:30 AM - 1:00 PM
Event Category:
Event Tags:
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Website:
Zoom: https://upenn.zoom.us/j/92183728423?pwd=qMHbQPpZgMzvfjpxjBYlKDYvsZpYQz.1

Organizer

Materials Science and Engineering
Phone
215-898-2462
Email
johnruss@seas.upenn.edu
View Organizer Website

Venue

LRSM Reading Room
3231 Walnut St.
Philadelphia, PA 19104 United States
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