Atomic Layer Deposition of a Nanometer-Thick Li3PO4 Protective Layer on LiNi0.5Mn1.5O4 Films: Dream or Reality for Long-Term Cycling?

Maxime Hallot; Borja Caja-Munoz; Clement Leviel; Oleg I Lebedev; Richard Retoux; José Avila; Pascal Roussel; Maria Carmen Asensio; Christophe Lethien

doi:10.1021/acsami.0c21961

Atomic Layer Deposition of a Nanometer-Thick Li₃PO₄ Protective Layer on LiNi_0.5Mn_1.5O₄ Films: Dream or Reality for Long-Term Cycling?

ACS Appl Mater Interfaces. 2021 Apr 7;13(13):15761-15773. doi: 10.1021/acsami.0c21961. Epub 2021 Mar 25.

Authors

Maxime Hallot^{1

2}, Borja Caja-Munoz³, Clement Leviel^{1

2

4}, Oleg I Lebedev⁵, Richard Retoux⁵, José Avila³, Pascal Roussel⁴, Maria Carmen Asensio⁶, Christophe Lethien^{1

2}

Affiliations

¹ Institut d'Electronique, de Microélectronique et de Nanotechnologies, Université de Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, UMR 8520-IEMN, F-59000 Lille, France.
² Réseau sur le Stockage Electrochimique de l'Energie (RS2E), CNRS FR 3459, 33 rue Saint Leu, 80039 Amiens Cedex, France.
³ Synchrotron-SOLEIL and Université Paris-Saclay Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
⁴ Unité de Catalyse et de Chimie du Solide (UCCS), Université de Lille, CNRS, Centrale Lille, Université d'Artois, UMR 8181-UCCS, F-59000 Lille, France.
⁵ Laboratoire CRISMAT, UMR6508, CNRS-ENSIACEN, 14050 Caen, France.
⁶ Materials Science Institute of Madrid (ICMM), Spanish Scientific Research Council (CSIC), Valencia Institute of Materials Science (ICMUV), MATINÉE: CSIC Associated Unit-(ICMM-ICMUV Valencia University), E-28049 Cantoblanco, Madrid, Spain.

PMID: 33765380
DOI: 10.1021/acsami.0c21961

Abstract

LiNi_0.5Mn_1.5O₄ (LNMO) is a promising 5V-class electrode for Li-ion batteries but suffers from manganese dissolution and electrolyte decomposition owing to the high working potential. An attractive solution to stabilize the surface chemistry consists in mastering the interface between the LNMO electrode and the liquid electrolyte with a surface protective layer made from the powerful surface deposition method. Here, we show that a 7400 nm thick sputtered LNMO film coated with a nanometer-thick lithium-ion-conductive Li₃PO₄ layer was deposited by the atomic layer deposition method. We demonstrate that this "material model system" can deliver a remarkable surface capacity (∼0.4 mAh cm^-2 at 1C) and exhibits improved cycling lifetime (×650%) compared to the nonprotected electrode. Nevertheless, we observe that mechanical failure occurs within the LNMO and Li₃PO₄ films when long-term cycling is performed. This in-depth study gives new insights regarding the mechanical degradation of LNMO electrodes upon charge/discharge cycling and reveals for the first time that the surface protective layer made from the ALD method is not sufficient for long-term stability applications.

Keywords: LiNi0.5Mn1.5O4; NEXAFS; XPS; atomic layer deposition; sputtering; surface chemistry; surface protective layer; thin film.