In situ X-ray absorption fine structure measurements of LaNi{sub 5} electrodes in alkaline electrolytes
- Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Chemistry
- Argonne National Lab., IL (United States). Chemistry Division
In situ Ni K-edge and La{sub m}-edge x-ray absorption fine structure (XAFS) measurements of LaNi{sub 5} electrodes supported on hydrophobic carbon black-polytetrafluoroethylene (PTFE) layers were carried out in strongly alkaline electrolytes as a function of the state of charge. The Ni K-edge X-ray absorption near-edge structure (XANES) for the material in the discharged (and uncharged) and charged states were essentially identical to those reported earlier for crystalline LaNi{sub 5} before and after exposure to gas-phase hydrogen, respectively. The Ni K-edge extended X-ray absorption fine structure (EXAFS) analysis of the most prominent shell yielded average Ni-Ni nearest neighbor distances of 2.52 {+-} 0.02 {angstrom} for the charged compared to 2.47 {+-} 0.02 {angstrom} for the discharged and uncharged electrodes. For the La L{sub m}-edge XANES, the white line was found to be significantly more intense for the charged than for the uncharged LaNi{sub 5}, an effect consistent with an increase in the density of empty d-like states just above the Fermi level on hydrogen injection.
- OSTI ID:
- 40321
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 3 Vol. 142; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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