Atomic-scale observation of phase transition of MgMn2O4 cubic spinel upon the charging in Mg-ion battery

Quang Duc Truong, Hiroaki Kobayashi, Keiichiro Nayuki, Yoshikazu Sasaki, Itaru Honma

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7 Citations (Scopus)


Direct observation of demagnesiated structure of MgMn2O4 spinel oxides at atomic scale has been achieved using spherical aberration-corrected scanning transmission electron microscopy (STEM) with high-angle annular-dark-field (HAADF) and annular-bright-field (ABF) techniques. Upon the Mg ions extraction from MgMn2O4 spinel oxides, structural transition from cubic to tetragonal phases was observed. The phase transition is a result of Mn octahedral distortion due to cooperative Jahn–Teller distortion of six-coordinate MnIII (t2g 3–eg 1). On the basis of HAADF/ABF micrographs and electron energy-loss spectrometer (EELS), it is suggested that Mn3+/Mn4+ and/or Mn3+/Mn5+ redox couples play a crucial role in the first electrochemical Mg deintercalation. This is the first report on observation of cubic-tetragonal phase transition in charged spinel MgMn2O4 which shed new insight into the magnesium storage mechanism in this important cathode material for Mg-ion batteries.

Original languageEnglish
Article number115136
JournalSolid State Ionics
Publication statusPublished - 2020 Jan

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics


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