Investigation on reversible hydrogen storage properties of Li3AlH6/2LiNH2 composite

To obtain promising materials for hydrogen storage, a composite of Li3AlH6 and LiNH2 with molar ratio of 1:2 was prepared by ball-milling, and its hydrogen storage properties were investigated. The microstructures of the composite after hydrogen desorption/absorption were characterized by XRD and FTIR analysis. The results show that 0.65 wt% H2 was released during ball-milling process and 5.97 wt% H2 was desorbed when the post-milled composite was heated from room temperature to 450 °C. The total hydrogen desorption capacity reached 6.62 wt%. And no NH3 is detected by the mass spectrum (MS) analysis over dehydrogenation process. The hydrogen desorption process of Li3AlH6/2LiNH2 composite occurs according to the following reaction: Li3AlH6 + 2LiNH2 → Li3AIN2 + 2LiH + 4H2. Furthermore, 3.57 wt% H2 can be reabsorbed at 400 °C and under hydrogen pressure of 110 bar.