Pulsed Laser Deposition and Characterization of Heteroepitaxial LiMn2O4/La0.5Sr0.5CoO3 Bilayer Thin Films as Model Lithium Ion Battery Cathodes

Xiankai Yu, Xiao Chen, D. Bruce Buchholz, Qianqian Li, Jinsong Wu, Paul A. Fenter, Michael J. Bedzyk, Vinayak P. Dravid, Scott A. Barnett*

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Epitaxial LiMn2O4 (LMO)/La0.5Sr0.5CoO3 (LSCO) bilayer thin films were grown on single crystalline SrTiO3 (STO) (111) substrates as model lithium ion battery cathodes. The LSCO layer was used as an electrically conducting buffer layer for electrochemical testing. The LMO and LSCO layers were both epitaxial, with sub-nano flat LMO/LSCO interfaces as seen by X-ray diffraction, synchrotron X-ray scattering, and high-resolution transmission electron microscopy (HRTEM), but with a large LMO surface roughness due to the relatively large lattice mismatch with LSCO. Three-dimensional islands and depressions were formed on the strain-relaxed LMO layer, and misfit dislocations at the LMO/LSCO interface were discerned through HRTEM imaging, suggesting a Stranski-Krastanov (SK) mode thin-film growth. A crystalline structural change from cubic spinel at the LMO surface and interior to tetragonal oxygen-deficient LMO at the LMO/LSCO interface was examined. Electrochemical tests along with in situ synchrotron X-ray scattering measurements on the epitaxial LMO/LSCO bilayers showed a significant loss of capacity after the first cycle, which was attributed to an electrical conductivity loss of the LSCO buffer layer due to irreversible lattice oxygen loss.

Original languageEnglish (US)
Pages (from-to)642-653
Number of pages12
JournalACS Applied Nano Materials
Volume1
Issue number2
DOIs
StatePublished - Feb 23 2018

Keywords

  • characterization
  • conductive buffer layer
  • crystal structure
  • heteroepitaxial thin film
  • interface
  • limnO
  • lithium ion battery

ASJC Scopus subject areas

  • Materials Science(all)

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