Surface Reconstruction in Li-Rich Layered Oxides of Li-Ion Batteries

Karalee Jarvis, Chih Chieh Wang, Maria Varela, Raymond R. Unocic, Arumugam Manthiram, Paulo J. Ferreira

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

The performance characteristics of lithium-ion battery cathode materials are governed by the surface structure and chemistry. Synthesis is known to affect the structure of these materials; however, a full understanding of the effects of the surface structure is not well understood. Here, we explore the atomic scale structure of lithium-layered oxides prepared with two different thermal treatments. We show that, under certain thermal treatments, the surface perpendicular to the transition-metal layers is enriched in nickel, which results in Ni occupying the lithium layer of the layered oxide structure. Under both thermal treatments, this surface also shows a reduction of Mn, with some of the reduced Mn occupying sites in the lithium layer. The surface parallel to the transition-metal layers under both treatments shows significant Mn reduction, oxygen loss, and reduced Mn in the lithium layer. The Mn reduction and surface reconstruction are the result of unstable surface terminations and are intrinsic to layered oxides. Synthesis can be tuned to eliminate Ni enrichment at the surface; however, it cannot be tailored to eliminate Mn reduction and surface reconstruction.

Original languageEnglish
Pages (from-to)7668-7674
Number of pages7
JournalChemistry of Materials
Volume29
Issue number18
DOIs
StatePublished - Sep 26 2017

Funding

The sample synthesis, experimental methodology and analysis, and part of the TEM work were supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award Number DE-SC0005397. Part of the TEM work at ORNL (M.V.) was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, and through a user project at the Center for Nanophase Materials Sciences (CNMS), which is U.S. DOE Office of Science User Facility (RRU). Part of the TEM work at University Complutense was supported by Spanish MINECO MAT2015-66888-C3-3-R and the ERC Proof of Concept MAGTOOLS.

FundersFunder number
U.S. Department of Energy
Office of Science
Basic Energy Sciences
Oak Ridge National Laboratory
Horizon 2020 Framework Programme713251
Division of Materials Sciences and EngineeringDE-SC0005397
Engineering Research Centers
Ministerio de Economía y CompetitividadMAT2015-66888-C3-3-R

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