First-principles study on Small Polaron and Li diffusion in layered LiCoO2

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Hauptverfasser: Ahn, Seryung, Kim, Jiyeon, Kim, Bongjae, Kim, Sooran
Format: Preprint
Veröffentlicht: 2022
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author Ahn, Seryung
Kim, Jiyeon
Kim, Bongjae
Kim, Sooran
author_facet Ahn, Seryung
Kim, Jiyeon
Kim, Bongjae
Kim, Sooran
contents Li-ion conductivity is one of the essential properties that determine the performance of cathode materials for Li-ion batteries. Here, using the density functional theory, we investigate the polaron stability and its effect on the Li-ion diffusion in layered LiCoO2 with different magnetic orderings. The localized Co4+ polaron appears in the magnetic configurations and sets the Li-diffusion barrier of ~0.34 eV. The polaron also migrates in the opposite direction to the Li-diffusion direction. On the other hand, the polaron does not form in the non-magnetic structure, and the Li diffusion barrier without the polaron is 0.21 eV. Although the existence of the polaron increases the diffusion barrier, the magnetically ordered structures are more energetically stable during the migration than the non-magnetic case. Thus, our work advocates the hole polaron migration scenario for Li-ion diffusion. Moreover, we demonstrate that the strong electron correlation of Co ions plays an essential role in stabilizing the Co4+ polaron.
format Preprint
id arxiv_https___arxiv_org_abs_2211_05464
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle First-principles study on Small Polaron and Li diffusion in layered LiCoO2
Ahn, Seryung
Kim, Jiyeon
Kim, Bongjae
Kim, Sooran
Materials Science
Li-ion conductivity is one of the essential properties that determine the performance of cathode materials for Li-ion batteries. Here, using the density functional theory, we investigate the polaron stability and its effect on the Li-ion diffusion in layered LiCoO2 with different magnetic orderings. The localized Co4+ polaron appears in the magnetic configurations and sets the Li-diffusion barrier of ~0.34 eV. The polaron also migrates in the opposite direction to the Li-diffusion direction. On the other hand, the polaron does not form in the non-magnetic structure, and the Li diffusion barrier without the polaron is 0.21 eV. Although the existence of the polaron increases the diffusion barrier, the magnetically ordered structures are more energetically stable during the migration than the non-magnetic case. Thus, our work advocates the hole polaron migration scenario for Li-ion diffusion. Moreover, we demonstrate that the strong electron correlation of Co ions plays an essential role in stabilizing the Co4+ polaron.
title First-principles study on Small Polaron and Li diffusion in layered LiCoO2
topic Materials Science
url https://arxiv.org/abs/2211.05464