Browsing by Subject "nanopore"

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    In Situ Focused Ion Beam-Scanning Electron Microscope Study of Crack and Nanopore Formation in Germanium Particle During (De)lithiation
    (ACS, 2019-04) Zhou, Xinwei; Li, Tianyi; Cui, Yi; Meyerson, Melissa L.; Mullins, C. Buddie; Liu, Yuzi; Zhu, Likun; Mechanical and Energy Engineering, School of Engineering and Technology
    Germanium has emerged as a promising high-capacity anode material for lithium ion batteries. To understand the microstructure evolution of germanium under different cycling rates, we monitored single germanium particle batteries using an in situ focused ion beam-scanning electron microscope. Our results show that both the lithium concentration and delithiation rate have an impact on nanopore formation. This study reveals that germanium electrodes with low and high cycling rates have better microstructure integrity, which leads to better cycling performance. The nanopores tend to aggregate into large porous structures during cycling which leads to particle pulverization and capacity fading of the electrode.
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    Lithium trapping in germanium nanopores during delithiation process
    (Elsevier, 2021-09) Zhou, Xinwei; Li, Tianyi; Cui, Yi; Meyerson, Melissa L.; Weeks, Jason A.; Mullins, C. Buddie; Yang , Shengfeng; Liu, Yuzi; Zhu, Likun; Mechanical and Energy Engineering, School of Engineering and Technology
    Irreversible capacity loss is a critical problem in high capacity anode materials of Li-ion batteries, such as silicon, germanium, and tin. In addition to solid electrolyte interface formation and active material loss, Li trapping in high capacity anode materials during cycling has been considered a new mechanism of capacity loss but received less attention. In this study, we used single particle battery-based in situ focused ion beam-scanning electron microscopy, transmission electron microscopy (TEM), and scanning TEM to investigate the microstructure and composition of germanium nanopores formed at the end of delithiation. Our results show that a significant amount of Li accumulates inside the nanopores.