Charge transfer kinetics at the solid–solid interface in porous electrodes
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Bazant_Charge transfers.pdf
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Author(s)
Bai, Peng
Bazant, Martin Z.
Date Issued
April 2014
Journal
Nature Communications
Publisher
Nature Publishing Group
Citation
Bai, Peng, and Martin Z. Bazant. “Charge Transfer Kinetics at the Solid–solid Interface in Porous Electrodes.” Nature Communications 5 (April 3, 2014).
Version
Author's final manuscript
Abstract
Interfacial charge transfer is widely assumed to obey the Butler–Volmer kinetics. For certain liquid–solid interfaces, the Marcus–Hush–Chidsey theory is more accurate and predictive, but it has not been applied to porous electrodes. Here we report a simple method to extract the charge transfer rates in carbon-coated LiFePO4 porous electrodes from chronoamperometry experiments, obtaining curved Tafel plots that contradict the Butler–Volmer equation but fit the Marcus–Hush–Chidsey prediction over a range of temperatures. The fitted reorganization energy matches the Born solvation energy for electron transfer from carbon to the iron redox site. The kinetics are thus limited by electron transfer at the solid–solid (carbon-LixFePO4) interface rather than by ion transfer at the liquid–solid interface, as previously assumed. The proposed experimental method generalizes Chidsey’s method for phase-transforming particles and porous electrodes, and the results show the need to incorporate Marcus kinetics in modelling batteries and other electrochemical systems.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mathematics
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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.
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DOI of Published Version
https://doi.org/10.1038/ncomms4585
