@article{25130,
  keywords = {sputtering, lithium, secondary cells, chromatography, electrochemical electrodes, electrochemical impedance spectroscopy, Fourier transform spectra, graphite, infrared spectra, mass spectra, Raman spectra, scanning electron microscopy, surface structure},
  author = {Laurence J Hardwick and Marek Marcinek and Leanne Beer and John B Kerr and Robert Kostecki},
  title = {An Investigation of the Effect of Graphite Degradation on Irreversible Capacity in Lithium-Ion Cells},
  abstract = {<p>The effect of surface structural damage on graphitic anodes, commonly observed in tested Li-ion cells, was investigated. Similar surface structural disorder was artificially induced in Mag-10 synthetic graphite anodes using argon-ion sputtering. Raman microscopy, scanning electron microscopy, and Brunauer–Emmett–Teller measurements confirmed that Ar-ion sputtered Mag-10 electrodes display a similar degree of surface degradation as the anodes from tested Li-ion cells. Artificially modified Mag-10 anodes showed double the irreversible charge capacity during the first formation cycle compared to fresh unaltered anodes. Impedance spectroscopy and Fourier transform infrared spectroscopy on surface-modified graphite anodes indicated the formation of a thicker and slightly more resistive solid electrolyte interphase (SEI) layer. Gas chromatography/mass spectroscopy analysis of solvent extracts from the electrodes detected the presence of new compounds with <em>M</em><sub>w</sub> on the order of 1600gmol<sup>−1</sup> for the surface-modified electrode with no evidence of elevated <em>M</em><sub>w</sub> species for the unmodified electrode. The structural disorder induced in the graphite during long-term cycling may be responsible for the slow and continuous SEI layer reformation, and consequently, the loss of reversible capacity due to the shift of lithium inventory in cycled Li-ion cells.</p>},
  year = {2008},
  journal = {Electrochemical Society},
  volume = {155},
  pages = {A442-A447},
  doi = {10.1149/1.2903882 },
  language = {eng},
}