Hydrogen desorption studies of NaAlH_4 and LiAlH_4 by in situ heating in an ESEM

摘要

As-received and ball milled/catalyzed samples of NaAlH_4 and LiAlH_4 were heated in an environmental scanning electron microscope (ESEM). Morphological changes during heating and hydrogen desorption were recorded in real time. Both as-received materials underwent dramatic morphological and destructive structural changes upon heating, whereas the ball milled/catalyzed samples showed a benign outgassing with little morphological change. These observations help explain why milled/catalyzed samples of metal hydrides perform better as reversible hydrogen storage materials than their unca-talyzed bretheren.