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This content will become publicly available on March 29, 2017

Title: Revealing the Restructured Surface of Li[Mn2]O4

The spinel Revealing the Restructured Surface of Li[Mn2]O4 is a candidate cathode for a Li-ion battery, but its capacity fades over a charge/discharge cycle of Li1–x[Mn2]O4 (0 < x < 1) that is associated with a loss of Mn to the organic-liquid electrolyte. It is known that the disproportionation reaction 2Mn3+ = Mn2+ + Mn4+ occurs at the surface of a Mn spinel, and it is important to understand the atomic structure and composition of the surface of Revealing the Restructured Surface of Li[Mn2]O4 in order to understand how Mn loss occurs. We report a study of the surface reconstruction of Revealing the Restructured Surface of Li[Mn2]O4 by aberration-corrected scanning transmission electron microscopy. The atomic structure coupled with Mn-valence and the distribution of the atomic ratio of oxygen obtained by electron energy loss spectroscopy reveals a thin, stable surface layer of Mn3O4, a subsurface region of Li1+x[Mn2]O4 with retention of bulk Li[Mn2]O4. We conclude that this observation is compatible with the disproportionation reaction coupled with oxygen deficiency and a displacement of surface Li+ from the Mn3O4 surface phase. These results provide a critical step toward understanding how Mn is lost from Li[Mn2]O4, once inside a battery.
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  1. Univ. of Texas at Austin, Austin, TX (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. Complutense Madrid (Spain)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 16; Journal Issue: 5; Journal ID: ISSN 1530-6984
American Chemical Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE EELS; HAADF STEM; LiMn2O4; Mn-disproportionation; surface reconstruction