Cristin-resultat-ID: 1953216
Sist endret: 15. februar 2022, 12:39
NVI-rapporteringsår: 2021
Resultat
Vitenskapelig artikkel
2021

Limitations of Ultrathin Al2O3 Coatings on LNMO Cathodes

Bidragsytere:
  • Elise Ramleth Østli
  • Yonas Tesfamhret
  • Sigurd Wenner
  • Matthew J. Lacey
  • Daniel Brandell
  • Ann Mari Svensson
  • mfl.

Tidsskrift

ACS Omega
ISSN 2470-1343
e-ISSN 2470-1343
NVI-nivå 1

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2021
Volum: 6
Hefte: 45
Sider: 30644 - 30655
Open Access

Importkilder

Scopus-ID: 2-s2.0-85119034935

Beskrivelse Beskrivelse

Tittel

Limitations of Ultrathin Al2O3 Coatings on LNMO Cathodes

Sammendrag

This study demonstrates the application of Al2O3 coatings for the high-voltage cathode material LiNi0.5–xMn1.5+xO4−δ (LNMO) by atomic layer deposition. The ultrathin and uniform coatings (0.6–1.7 nm) were deposited on LNMO particles and characterized by scanning transmission electron microscopy, inductively coupled plasma mass spectrometry, and X-ray photoelectron spectroscopy. Galvanostatic charge discharge cycling in half cells revealed, in contrast to many published studies, that even coatings of a thickness of 1 nm were detrimental to the cycling performance of LNMO. The complete coverage of the LNMO particles by the Al2O3 coating can form a Li-ion diffusion barrier, which leads to high overpotentials and reduced reversible capacity. Several reports on Al2O3-coated LNMO using alternative coating methods, which would lead to a less homogeneous coating, revealed the superior electrochemical properties of the Al2O3-coated LNMO, suggesting that complete coverage of the particles might in fact be a disadvantage. We show that transition metal ion dissolution during prolonged cycling at 50 °C is not hindered by the coating, resulting in Ni and Mn deposits on the Li counter electrode. The Al2O3-coated LNMO particles showed severe signs of pitting dissolution, which may be attributed to HF attack caused by side reactions between the electrolyte and the Al2O3 coating, which can lead to additional HF formation. The pitting dissolution was most severe for the thickest coating (1.7 nm). The uniform coating coverage may lead to non-uniform conduction paths for Li, where the active sites are more susceptible to HF attack. Few benefits of applications of very thin, uniform, and amorphous Al2O3 coatings could thus be verified, and the coating is not offering long-term protection from HF attack.

Bidragsytere

Elise Ramleth Østli

  • Tilknyttet:
    Forfatter
    ved Institutt for materialteknologi ved Norges teknisk-naturvitenskapelige universitet

Yonas Tesfamhret

  • Tilknyttet:
    Forfatter
    ved Uppsala universitet

Sigurd Wenner

  • Tilknyttet:
    Forfatter
    ved Materialer og nanoteknologi ved SINTEF AS

Matthew Lacey

Bidragsyterens navn vises på dette resultatet som Matthew J. Lacey
  • Tilknyttet:
    Forfatter
    ved Sverige

Daniel Brandell

  • Tilknyttet:
    Forfatter
    ved Uppsala universitet
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