Operando soft x-ray emission spectroscopy of LiMn2O4 thin film involving Li-ion extraction/insertion reaction

Daisuke Asakura, Eiji Hosono, Hideharu Niwa, Hisao Kiuchi, Jun Miyawaki, Yusuke Nanba, Masashi Okubo, Hirofumi Matsuda, Haoshen Zhou, Masaharu Oshima, Yoshihisa Harada

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

We developed an electrochemical in situ cell for soft x-ray emission spectroscopy (XES) to accurately investigate the redox reaction and electronic structure of transition metals in the cathode materials for Li-ion battery. The in situ cell consists of a Li-metal counter electrode, an organic electrolyte solution, and a cathode on a membrane window which separates the liquid electrolyte from high vacuum and can pass the incoming and emitted photons. In this study, the Mn 3d electronic structure of LiMn2O4 thin-film electrodewas clarified by the operando XES. At the charged state, the XES spectrum changed significantly from the open-circuit-voltage (OCV) state, suggesting oxidation of the Mn3+ component through Li-ion extraction. Upon discharge up to 3.0 V vs. Li/Li+, the XES spectrum almost returned to its profile at the OCV state with small difference, indicating the valence change of Mn: Mn3.6+ → Mn4+ → Mn3.3+ corresponding to the OCV, charged, and discharged states.

Original languageEnglish
Pages (from-to)93-96
Number of pages4
JournalElectrochemistry Communications
Volume50
DOIs
Publication statusPublished - 2015 Jan
Externally publishedYes

Keywords

  • In situ
  • Li-ion battery
  • LiMno
  • Operando
  • Soft x-ray emission spectroscopy

ASJC Scopus subject areas

  • Electrochemistry

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