Soft x-ray irradiation effects of Li₂O₂, Li₂CO₃ and Li₂O revealed by absorption spectroscopy

PLoS One. 2012;7(11):e49182. doi: 10.1371/journal.pone.0049182. Epub 2012 Nov 7.

Abstract

Li(2)O(2), Li(2)CO(3), and Li(2)O are three critical compounds in lithium-air and lithium-ion energy storage systems. Extensive measurements have been carried out to study the chemical species and their evolutions at difference stages of the device operation. While x-ray spectroscopy has been demonstrated to be one of the most powerful tools for such purpose, no systematic study on the irradiation effects have been reported. Here we carry out extensive time, position, and irradiation dependent Li K-edge soft x-ray absorption spectroscopy on these compounds with so far the best energy resolution. The ultra-high resolution in the current study allows the features in the absorption spectra to be well-resolved. The spectral lineshape thus serves as the fingerprints of these compounds, enabling the tracking of their evolution under x-ray irradiation. We found that both Li(2)O(2) and Li(2)CO(3) evidently evolve towards Li(2)O under the soft x-ray irradiation with Li(2)CO(3) exhibiting a surprisingly higher sensitivity to x-rays than Li(2)O(2). On the other hand, Li(2)O remains the most stable compound despite experiencing substantial irradiation dose. We thus conclude that high resolution soft x-ray spectroscopy could unambiguously fingerprint different chemical species, but special cautions on irradiation effects would be needed in performing the experiments and interpreting the data properly.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Absorption / radiation effects*
  • Ions / chemistry
  • Lithium / chemistry*
  • Oxides / chemistry*
  • X-Ray Absorption Spectroscopy*
  • X-Rays

Substances

  • Ions
  • Oxides
  • Lithium

Grants and funding

The Advanced Light Source at Lawrence Berkeley National Laboratory was supported by the U. S. Department of Energy (http://energy.gov) under Contract No. DE-AC02-05CH11231. This work was also supported by National Natural Science Foundation of China (http://www.nsfc.gov.cn) No.51125004 and No.10974120, and the National Basic Research Program of China (http://www.973.gov.cn) No. 2013CB922303. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.