Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes
Name
CurrentInducedManuscript.pdf
Size
2.44 MB
Format
Adobe PDF
Checksum (MD5)
bc38276db2192debe9384477c9aabd4a
Author(s)
Li, Yiyang
El Gabaly, Farid
Bartelt, Norman C.
Sugar, Joshua D.
Fenton, Kyle R.
Cogswell, Daniel A.
Kilcoyne, A. L. David
Tyliszczak, Tolek
Chueh, William C.
Ferguson, Todd Richard
Date Issued
September 2014
Journal
Nature Materials
Publisher
Nature Publishing Group
Citation
Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R. et al. “Current-Induced Transition from Particle-by-Particle to Concurrent Intercalation in Phase-Separating Battery Electrodes.” Nature Materials 13, 12 (September 2014): 1149–1156 © 2014 Macmillan Publishers Limited, part of Springer Nature
Version
Author's final manuscript
Abstract
Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mathematics
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/nmat4084
