Hydrogen generation by the hydrolysis reaction of ball-milled aluminium–lithium alloys

Abstract

The addition of Li can prevent an inert alumina film from forming on the surface of Al alloy particles, allowing the rapid hydrogen generation of Al alloys to be achieved. However, because the Li content is less than 10%, the hydrogen generation rate and hydrogen yield of Al–Li alloys are significantly decreased. In this work, NaCl is introduced to prepare Al–Li alloys with low Li contents by ball milling. The research results show that by increasing the amount of NaCl added, the ball milling time and Li content can effectively improve the hydrogen generation of the alloys. Under optimal preparation conditions, the ultimate hydrogen yield of Al–Li alloys can reach 100%. The initial water temperature has almost no effect on the generation of hydrogen, even at 0 °C. Ca2+ and Mg2+ can combine with OH− to form the insoluble compounds Ca(OH)2 and Mg(OH)2, which can prevent hydrogen generation. NO3− reacts with Al to form ammonia and reduce the hydrogen yield of the alloys. Therefore, Al–Li alloys should be prevented from reacting with water containing Ca2+, Mg2+ and NO3−. Al–Li alloys must be stored in isolation from air to maintain good hydrogen-generation performances.