論文

査読有り
2017年4月

Direct observation of layered-to-spinel phase transformation in Li2MnO3 and the spinel structure stabilised after the activation process

JOURNAL OF MATERIALS CHEMISTRY A
  • Keiji Shimoda
  • Masatsugu Oishi
  • Toshiyuki Matsunaga
  • Miwa Murakami
  • Keisuke Yamanaka
  • Hajime Arai
  • Yoshio Ukyo
  • Yoshiharu Uchimoto
  • Toshiaki Ohta
  • Eiichiro Matsubarad
  • Zempachi Ogumia
  • 全て表示

5
14
開始ページ
6695
終了ページ
6707
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1039/c6ta11151c
出版者・発行元
ROYAL SOC CHEMISTRY

Li2MnO3 is an important parent component in lithium-and manganese-rich layered oxides (LMRs), which are one of the promising positive electrode materials for next-generation lithium ion rechargeable batteries. Here, we report the layered-to-spinel phase transformation in Li2MnO3 during the initial charging process to characterise its unique delithiation behaviour, which gives an insight into the relationship between the structure, superior capacities and degradation of LMR electrodes. The atomic-scale observation using scanning transmission electron microscopy (STEM) techniques suggests that the structural transformation occurs in a biphasic manner within a single particle. The formed phase has a Li-defect spinel structure, indicating that the delithiation leads to Mn migration from the transition-metal layer to the Li layer, accompanied by some oxygen release. This layered-to-spinel phase transformation is an essential bulk process in the initial activation of Li2MnO3. During the lithiation in the 1st discharge, the Mn remigration occurs and the layered structure is again formed with significant disordering. During the multiple cycles, the defect spinel structure is stabilised and becomes more oxygen-deficient with a lower Mn valency. As a consequence, the amount of inserted Li decreases, which corresponds to the capacity and voltage fading observed in Li2MnO3 and LMRs.

リンク情報
DOI
https://doi.org/10.1039/c6ta11151c
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000398323400040&DestApp=WOS_CPL
URL
http://orcid.org/0000-0003-4600-3437
ID情報
  • DOI : 10.1039/c6ta11151c
  • ISSN : 2050-7488
  • eISSN : 2050-7496
  • ORCIDのPut Code : 31284175
  • Web of Science ID : WOS:000398323400040

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