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Published October 31, 2007 | public
Journal Article

NMR to determine rates of motion and structures in metal-hydrides

Abstract

Measurements of nuclear magnetic resonance (NMR) relaxation times allow the rates of H and D atomic hopping in metal-hydrides to be determined. A first example compares the rates of H hopping in Mg_(65)Sc_(35)Pd_(2.4)H_(220), a promising new battery electrode and storage alloy, to LaNi_5H_x and to the end-members of the alloy system, ScH_2 and MgH_2. The motion of MgScH is more rapid than in the metallic ScH_2 and the ionic MgH_2, but slower than in LaNi_5H_x. Magic-angle spinning (MAS) NMR of metal-deuterides is a newer method that can resolve inequivalent D atoms and measure the rate of diffusive exchange between the sites. Examples include the tetrahedral and octahedral sites in YD_(2+x) and D in ZrNiD_x.

Additional Information

© 2006 Elsevier B.V. Received 26 September 2006; accepted 16 November 2006. Available online 2 January 2007. The authors acknowledge support from NSF grant DMR-0400512 and DOE grants DE-FG02-05ER46256 and DEAI- 01-05EE11105. The ZrNiDx work was performed under NSF grant DMR-9804094 and Research Corp. grant CC4705. The research was partially performed at Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautical and Space Administration. The effort of the Caltech NMR facility was supported under NSF grants 97243240 and DMR-0080065(MRSEC program).We thank T.J. Udovic and the authors of Ref. [26] for use of their data. The research on MgSc hydrides was performed as part of the Sustainable Hydrogen Program of Active Chemical Technologies for Sustainability (ACTS).

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023