Li+/H+ exchange in solid-state oxide Li-ion conductors

Fuente: arXiv
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Main Authors: Li, Zhuohan, Lam, Benjamin X., Wang, Shilong, Ceder, Gerbrand
Format: Preprint
Published: 2025
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author Li, Zhuohan
Lam, Benjamin X.
Wang, Shilong
Ceder, Gerbrand
author_facet Li, Zhuohan
Lam, Benjamin X.
Wang, Shilong
Ceder, Gerbrand
contents Understanding the moisture stability of oxide Li-ion conductors is important for their practical applications in solid-state batteries. Unlike sulfide or halide conductors, oxide conductors generally better resist degradation when in contact with water, but can still undergo topotactic \ch{Li+}/\ch{H+} exchange (LHX). Here, we combine density functional theory (DFT) calculations with a machine-learning interatomic potential model to investigate the thermodynamic driving force of the LHX reaction for two representative oxide Li-ion conductor families: garnets and NASICONs. Li-stuffed garnets exhibit a strong driving force for proton exchange due to their high Li chemical potential. In contrast, NASICONs demonstrate a higher resistance against proton exchange due to the lower Li chemical potential and the lower O-H bond covalency for polyanion-bonded oxygens. Our findings reveal a critical trade-off: Li stuffing enhances conductivity but increases moisture susceptibility. This study underscores the importance of designing Li-ion conductors that possess both high conductivity and high stability in practical environments.
format Preprint
id arxiv_https___arxiv_org_abs_2509_13477
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Li+/H+ exchange in solid-state oxide Li-ion conductors
Li, Zhuohan
Lam, Benjamin X.
Wang, Shilong
Ceder, Gerbrand
Materials Science
Understanding the moisture stability of oxide Li-ion conductors is important for their practical applications in solid-state batteries. Unlike sulfide or halide conductors, oxide conductors generally better resist degradation when in contact with water, but can still undergo topotactic \ch{Li+}/\ch{H+} exchange (LHX). Here, we combine density functional theory (DFT) calculations with a machine-learning interatomic potential model to investigate the thermodynamic driving force of the LHX reaction for two representative oxide Li-ion conductor families: garnets and NASICONs. Li-stuffed garnets exhibit a strong driving force for proton exchange due to their high Li chemical potential. In contrast, NASICONs demonstrate a higher resistance against proton exchange due to the lower Li chemical potential and the lower O-H bond covalency for polyanion-bonded oxygens. Our findings reveal a critical trade-off: Li stuffing enhances conductivity but increases moisture susceptibility. This study underscores the importance of designing Li-ion conductors that possess both high conductivity and high stability in practical environments.
title Li+/H+ exchange in solid-state oxide Li-ion conductors
topic Materials Science
url https://arxiv.org/abs/2509.13477