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Title: Surface Morphology and Surface Stability against Oxygen Loss of the Lithium-Excess Li 2MnO 3 Cathode Material as a Function of Lithium Concentration

There is a growing appreciation for the role of surface reactivity and subsequent reconstruction affecting the performance of high-voltage, high-capacity Li-ion cathode materials. In particular, the promising Li-excess materials are known to exhibit significant vulnerability toward oxygen release, which can cause surface densification and impede Li intercalation. In this work, we focus on the end member, Li 2MnO 3, as a Li-excess, Mn-rich representative of this class of materials and systematically elucidate all possible stoichiometric low Miller index surfaces with various cation ordering on each surface. We apply surface cation reconstruction rules that depend on the local environment, including target Mn-Li site exchanges, and optimize the resulting surface Li configurations using metadynamics. The equilibrium Wulff shape shows dominant (001), (010) surface facets, and almost all facets exhibit favorable Mn reconstruction. Most importantly, we find that while all equilibrium Li xMnO 3 surfaces become unstable toward oxygen release for x < 1.7, some facets are consistently more resistant than others which may provide a design metric for more stable particle morphologies and enhanced surface oxygen retention.
Authors:
 [1] ;  [2]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division; Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 8; Journal Issue: 38; Related Information: © 2016 American Chemical Society.; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; cathode; layered Li-excess; Li-ion battery; oxygen evolution; surface morphology
OSTI Identifier:
1474968

Shin, Yongwoo, and Persson, Kristin A. Surface Morphology and Surface Stability against Oxygen Loss of the Lithium-Excess Li2MnO3 Cathode Material as a Function of Lithium Concentration. United States: N. p., Web. doi:10.1021/acsami.6b07259.
Shin, Yongwoo, & Persson, Kristin A. Surface Morphology and Surface Stability against Oxygen Loss of the Lithium-Excess Li2MnO3 Cathode Material as a Function of Lithium Concentration. United States. doi:10.1021/acsami.6b07259.
Shin, Yongwoo, and Persson, Kristin A. 2016. "Surface Morphology and Surface Stability against Oxygen Loss of the Lithium-Excess Li2MnO3 Cathode Material as a Function of Lithium Concentration". United States. doi:10.1021/acsami.6b07259. https://www.osti.gov/servlets/purl/1474968.
@article{osti_1474968,
title = {Surface Morphology and Surface Stability against Oxygen Loss of the Lithium-Excess Li2MnO3 Cathode Material as a Function of Lithium Concentration},
author = {Shin, Yongwoo and Persson, Kristin A.},
abstractNote = {There is a growing appreciation for the role of surface reactivity and subsequent reconstruction affecting the performance of high-voltage, high-capacity Li-ion cathode materials. In particular, the promising Li-excess materials are known to exhibit significant vulnerability toward oxygen release, which can cause surface densification and impede Li intercalation. In this work, we focus on the end member, Li2MnO3, as a Li-excess, Mn-rich representative of this class of materials and systematically elucidate all possible stoichiometric low Miller index surfaces with various cation ordering on each surface. We apply surface cation reconstruction rules that depend on the local environment, including target Mn-Li site exchanges, and optimize the resulting surface Li configurations using metadynamics. The equilibrium Wulff shape shows dominant (001), (010) surface facets, and almost all facets exhibit favorable Mn reconstruction. Most importantly, we find that while all equilibrium LixMnO3 surfaces become unstable toward oxygen release for x < 1.7, some facets are consistently more resistant than others which may provide a design metric for more stable particle morphologies and enhanced surface oxygen retention.},
doi = {10.1021/acsami.6b07259},
journal = {ACS Applied Materials and Interfaces},
number = 38,
volume = 8,
place = {United States},
year = {2016},
month = {9}
}