Microstructural changes in LiNi0.8Co0.15Al 0.05O2 positive electrode material during the first cycle

Shijian Zheng, Rong Huang, Yoshinari Makimura, Yoshio Ukyo, Craig A.J. Fisher, Tsukasa Hirayama, Yuichi Ikuhara

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    120 Citations (Scopus)

    Abstract

    The microstructure of LiNi0.8Co0.15Al 0.05O2 positive electrode material before and after the first cycle was investigated by scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS). STEM and EELS analysis shows that, before cycling, there are very thin layers of material at grain boundaries that contain a small amount of transition metal ions (particularly Ni) on Li sites. After the first cycle, the thickness of some grain boundary layers increases significantly, accompanied by formation of microcracks at grain boundaries. Also, from the grain interior to the grain boundary, the structure gradually changes from an ordered layer structure (α-NaFeO 2-type) to a partially ordered structure and then to a disordered rock-salt structure. We posit that these microstructural changes are primarily responsible for the irreversible capacity during the first cycle.

    Original languageEnglish
    JournalJournal of the Electrochemical Society
    Volume158
    Issue number4
    DOIs
    Publication statusPublished - 2011 Apr 29

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Renewable Energy, Sustainability and the Environment
    • Surfaces, Coatings and Films
    • Electrochemistry
    • Materials Chemistry

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