Hydrogen reactivity of Li-containing hydrogen storage materials

Abstract

In hydrogen energy systems, the hydrogen storage alloy is expected as one of important materials for energy storage and transportation. However, they weigh so much for sufficient amounts of hydrogen, therefore, light hydrogen storage materials with much higher storage capacities are required. Alkaline complex hydrides are promising candidates as light hydrogen storage materials. In this study we tried to prepare a sample based on the Na–Li–Al system using the dry process of ball-milling as mechanical synthesis and investigate their hydrogen reaction characteristics. The same study for the sample with 10 wt.% La2O3 was also carried out and its hydrogen reactivity compared. The starting materials were LiAlH4, NaH. They were ball-milled with hexane dehydrated in 1 bar Ar. The hydrogen reactivity of the samples obtained were measured by the high-pressure Sievert’s type apparatus. For the sample of NaH+LiH+Al, about 1.9∼2.0 wt.% of hydrogen was absorbed reversibly within 150 min. The addition of 10 wt.% La2O3 improved both the ab/desorption reaction rate and cyclable hydrogen capacity.