• Title of article

    Investigation of positive electrodes after cycle testing of high-power Li-ion battery cells: I. An approach to the power fading mechanism using XANES

  • Author/Authors

    Hironori Kobayashi، نويسنده , , Masahiro Shikano، نويسنده , , Shinji Koike، نويسنده , , Hikari Sakaebe، نويسنده , , Kuniaki Tatsumi، نويسنده ,

  • Issue Information
    روزنامه با شماره پیاپی سال 2007
  • Pages
    7
  • From page
    380
  • To page
    386
  • Abstract
    Cylindrical lithium-ion (Li-ion) cells with a nickel-cobalt oxide (LiNi0.73Co0.17Al0.10O2) positive electrode and a non-graphitizable carbon (hard carbon) negative electrode were degraded using cycle tests. The degraded cells were disassembled and examined; most attention was paid to the positive electrodes in order to clarify the origin of the power fade of the cells. X-ray absorption near-edge structure (XANES) analysis demonstrated that the crystal structure of the electrode at the surface changed from rhombohedral to cubic symmetry. Furthermore, a film of lithium carbonate (Li2CO3) covered the surface of the positive electrode after the cycle tests. Using a combination of X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), and glow discharge optical emission spectrometry (GD-OES) measurements, a schematic model of the changes occurring in the surface structure of the positive electrode during the cycle tests was constructed. The appearance of both an electrochemically inactive cubic phase and lithium carbonate films at the surface of the positive electrode are important factors giving rise to power fade of the positive electrode.
  • Keywords
    layered oxides , synchrotron radiation , XAFS measurements , Lithium nickel-based oxide , Cathode material for lithium secondary batteries
  • Journal title
    Journal of Power Sources
  • Serial Year
    2007
  • Journal title
    Journal of Power Sources
  • Record number

    442092