Transport of secondary carriers in a solid lithium-ion conductor

Li, G. and Monroe, C. W. (2021) Transport of secondary carriers in a solid lithium-ion conductor. Electrochimica Acta, 389, 138563. (doi: 10.1016/j.electacta.2021.138563)

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Inorganic-solid lithium electrolytes are typically thought of as single-ion conductors, but the presence of secondary carriers can strongly affect their performance. Conventional descriptions of multi-carrier transport neglect both interactions between mobile species and stress diffusion — phenomena which can markedly impact the electrical response. We apply irreversible thermodynamics to develop a chemomechanical transport model for elastic-solid ionic conductors containing two mobile ions. We simulate lithium-ion conducting Li5La3Nb2O12 (LLNO) garnet oxide, a material within which experiments have shown that mobile protons can be freely substituted for lithium to form Li5(1−y)H5yLa3Nb2O12. When subjected to a current, we find that proton-substituted LLNO exhibits bulk lithium polarization, whose extent is partially controlled by cation/cation interactions. Secondary carriers segregate naturally if their global concentration is low, accumulating in a thin boundary layer near the cathode. We quantify the limiting current and Sand’s time, and analyze experimental data to show how competitive proton transport affects LLNO performance.

Item Type:Articles
Additional Information:This work was supported by the Faraday Institution, within the SOLBAT challenge, grant no. EP/S003053/1.FIRG007, and by the UK Engineering and Physical Sciences Research Council (EPSRC) under grant no. EP/P003532/1.
Glasgow Author(s) Enlighten ID:Li, Dr Guanchen
Creator Roles:
Li, G.Conceptualization, Methodology, Investigation, Writing – original draft
Authors: Li, G., and Monroe, C. W.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Electrochimica Acta
ISSN (Online):1873-3859
Published Online:08 June 2021
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in Electrochimica Acta 389: 138563
Publisher Policy:Reproduced under a Creative Commons License

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