Kinetic Study of Lithiation-Induced Phase Transitions in Amorphous Germanium Thin Films
Name
Miao_2020_J._Electrochem._Soc._167_090557.pdf
Description
Published version
Size
1.85 MB
Format
Adobe PDF
Checksum (MD5)
d99c9b80896ec25a334a121635109f71
Author(s)
Miao, Jinghui
Wang, Baoming
Thompson, Carl Vernette
Date Issued
July 2020
Journal
Journal of the Electrochemical Society
Publisher
The Electrochemical Society
Citation
Miao, Jinghui, Baoming Wang, and Carl V. Thompson. “Kinetic Study of Lithiation-Induced Phase Transitions in Amorphous Germanium Thin Films.” Journal of the Electrochemical Society, 167, 9 (July 2020): © 2020 The Author(s)
Version
Final published version
Abstract
Mechanisms of the reversible lithiation of amorphous germanium thin films were studied using electrochemical and structural characterization techniques. Cyclic voltammograms (CV) exhibited major lithiation peaks and delithiation peaks, the latter of which turned out to be highly dependent on the lithiation cutoff voltage and closely associated with the formation of the crystalline phase c-Li15Ge4. Through detailed analyses of CV and potentiostatic tests we demonstrate that the features of electrochemically induced phase transitions vary with lithiation voltage. A surprising finding is that two phase transitions occur simultaneously in the 0.29-0.14 V range. In this regime, three phases, two amorphous phases with different stoichiometries and the crystalline phase, can co-exist. The cycle-number dependence of formation of the crystalline phase as well as structural analyses suggest that crack formation may play an important role in reducing the kinetic barrier associated with crystallization. This study sheds new light on the kinetic constraints on lithiation of a-Ge and yields insight for electrode design and development of cycling schemes for optimized performance and cyclability.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1149/1945-7111/ab9eec
