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Off-stoichiometry, vacancy trapping, and pseudo-irreversible first-cycle capacity in LiNiO₂

Sicolo, Sabrina ; Sadowski, Marcel ; Vettori, Kilian ; Bianchini, Matteo ; Janek, Jürgen ; Albe, Karsten (2024)
Off-stoichiometry, vacancy trapping, and pseudo-irreversible first-cycle capacity in LiNiO₂.
In: Chemistry of Materials, 36 (1)
doi: 10.1021/acs.chemmater.3c02534
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

We demonstrate that the ubiquitous off-stoichiometry of LiNiO2 in the form of Li1–zNi1+zO2 slows the kinetics of the material by both diminishing the number of ionic charge carriers and increasing the length of diffusion paths. The positive charge of excess Ni in the Li layer, along with the accompanying local chemomechanical strain, creates an attractive potential for Li vacancies, thereby reducing their energy compared to defect-free regions. This attractive field extends over a radius of two lattice sites and also considerably lowers the migration barrier for a Li vacancy to approach the defect, effectively making excess Ni a sink for lithium vacancies. A similar argument can be made for divacancies, which are split by the extra Ni and pinned in the form of single vacancies. In addition to pinning effects, which could vary depending on the Li concentration, excess Ni also constitutes an obstacle to Li migration because it is rather immobile and does not undergo site exchange with an adjacent Li vacancy.

Typ des Eintrags: Artikel
Erschienen: 2024
Autor(en): Sicolo, Sabrina ; Sadowski, Marcel ; Vettori, Kilian ; Bianchini, Matteo ; Janek, Jürgen ; Albe, Karsten
Art des Eintrags: Bibliographie
Titel: Off-stoichiometry, vacancy trapping, and pseudo-irreversible first-cycle capacity in LiNiO₂
Sprache: Englisch
Publikationsjahr: 2024
Ort: Washington, DC
Verlag: ACS
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Chemistry of Materials
Jahrgang/Volume einer Zeitschrift: 36
(Heft-)Nummer: 1
DOI: 10.1021/acs.chemmater.3c02534
Kurzbeschreibung (Abstract):

We demonstrate that the ubiquitous off-stoichiometry of LiNiO2 in the form of Li1–zNi1+zO2 slows the kinetics of the material by both diminishing the number of ionic charge carriers and increasing the length of diffusion paths. The positive charge of excess Ni in the Li layer, along with the accompanying local chemomechanical strain, creates an attractive potential for Li vacancies, thereby reducing their energy compared to defect-free regions. This attractive field extends over a radius of two lattice sites and also considerably lowers the migration barrier for a Li vacancy to approach the defect, effectively making excess Ni a sink for lithium vacancies. A similar argument can be made for divacancies, which are split by the extra Ni and pinned in the form of single vacancies. In addition to pinning effects, which could vary depending on the Li concentration, excess Ni also constitutes an obstacle to Li migration because it is rather immobile and does not undergo site exchange with an adjacent Li vacancy.

Freie Schlagworte: BAT, UNIKAM
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Published online 26 December 2023.

Fachbereich(e)/-gebiet(e): 11 Fachbereich Material- und Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung
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Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ)
Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) > Hochleistungsrechner
Hinterlegungsdatum: 01 Mär 2024 10:56
Letzte Änderung: 06 Aug 2024 09:49
PPN: 520378733
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