AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP27
Lithium Hydride and Lithium Amide for Hydrogen Storage

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Surface Science Poster Session
Presenter: J. Engbaek, Technical University of Denmark
Authors: J. Engbaek, Technical University of Denmark
G. Nielsen, Technical University of Denmark
I. Chorkendorff, Technical University of Denmark
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Hydrogen storage is a serious showstopper for using hydrogen in the transport sector therefore this field has gained renewed interest. Lithium amid has a high hydrogen storage capability; 10.4wt.% hydrogen. In this study surface reactions of thin films of lithium with hydrogen and ammonia is studied under well controlled conditions with pure hydrogen and ammonia in a UHV-chamber. Thin well-characterized Lithium films from sub monolayer to several monolayers were grown on a nickel(111). The films of pure lithium and films reacted with hydrogen and ammonia were characterized with Auger, TPD and LEED. From the LEED patterns we have found that one monolayer of pure lithium form a stable 4x4 reconstructed surface with a coverage of 3 Li atoms to 4 Ni atoms. Lithium hydride was made by exposing a pure lithium film utilizing an atomic hydrogen source. TPD experiments were used to investigate the stability of the lithium / lithium hydride films and surprisingly we have found that lithium evaporate before lithium hydride. Similarly the stability of the lithium hydride / lithium amid was investigated by evaporating Lithium in an atmosphere of ammonia to make thin films of lithium amid. TPD experiments showed that lithium amid decompose at an even higher temperature than lithium hydride and lithium. This significantly complicates the use of lithium amid powder as a hydrogen storage system. The results made under UHV are compared to experiments on ball milled lithium hydride and lithium amid powders.