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Planar gliding and vacancy condensation: the role of dislocations in the chemomechanical degradation of layered transition-metal oxides

Sadowski, Marcel ; Koch, Leonie ; Albe, Karsten ; Sicolo, Sabrina (2022)
Planar gliding and vacancy condensation: the role of dislocations in the chemomechanical degradation of layered transition-metal oxides.
In: Chemistry of Materials, 35 (2)
doi: 10.1021/acs.chemmater.2c03069
Article, Bibliographie

Abstract

Stacking faults driven by dislocations have been observed in layered transition-metal oxide cathodes both in cycled and uncycled materials. The reversibility of stacking-sequence changes directly impacts the material performance. Irreversible glide due to lattice invariance or local compositional changes can initiate a catastrophic sequence of degradation mechanisms. In this study we compare the chemomechanical properties of LiCoO2 and LiNiO2 by combining density functional theory and anisotropic linear elasticity theory. We calculate stacking fault energies as a function of Li content and quantify the extent to which excess Ni hinders stacking-sequence changes. We then characterize screw dislocations, which mediate stacking-sequence changes, and find a peculiarly compliant behavior of LiNiO2 due to the interaction of Jahn–Teller distortions with the dislocation strain field. Finally, we analyze the tendency of vacancies to segregate along dislocation lines. This study represents the first instance of explicit ab initio atomistic dislocation models in layered oxides and paves the way for the understanding and optimization of the chemomechanical behavior of cathode active materials during battery operation.

Item Type: Article
Erschienen: 2022
Creators: Sadowski, Marcel ; Koch, Leonie ; Albe, Karsten ; Sicolo, Sabrina
Type of entry: Bibliographie
Title: Planar gliding and vacancy condensation: the role of dislocations in the chemomechanical degradation of layered transition-metal oxides
Language: English
Date: 30 December 2022
Publisher: ACS Publications
Journal or Publication Title: Chemistry of Materials
Volume of the journal: 35
Issue Number: 2
DOI: 10.1021/acs.chemmater.2c03069
Abstract:

Stacking faults driven by dislocations have been observed in layered transition-metal oxide cathodes both in cycled and uncycled materials. The reversibility of stacking-sequence changes directly impacts the material performance. Irreversible glide due to lattice invariance or local compositional changes can initiate a catastrophic sequence of degradation mechanisms. In this study we compare the chemomechanical properties of LiCoO2 and LiNiO2 by combining density functional theory and anisotropic linear elasticity theory. We calculate stacking fault energies as a function of Li content and quantify the extent to which excess Ni hinders stacking-sequence changes. We then characterize screw dislocations, which mediate stacking-sequence changes, and find a peculiarly compliant behavior of LiNiO2 due to the interaction of Jahn–Teller distortions with the dislocation strain field. Finally, we analyze the tendency of vacancies to segregate along dislocation lines. This study represents the first instance of explicit ab initio atomistic dislocation models in layered oxides and paves the way for the understanding and optimization of the chemomechanical behavior of cathode active materials during battery operation.

Additional Information:

This work was supported by BASF SE.

Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
DFG-Collaborative Research Centres (incl. Transregio)
DFG-Collaborative Research Centres (incl. Transregio) > Transregios
DFG-Collaborative Research Centres (incl. Transregio) > Transregios > CRC/TRR 270 HoMMage
Zentrale Einrichtungen
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ)
Date Deposited: 14 Jul 2023 06:59
Last Modified: 17 Jul 2023 06:24
PPN: 509639011
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