Synthesis of Li2NH Hollow Nanospheres with Superior Hydrogen Storage Kinetics by Plasma Metal Reaction

Li2NH hollow nanospheres were prepared by plasma metal reaction based on the Kirkendall effect. In this synthesis, the bulk lithium was vaporized and reacted with ammonia to obtain the hollow nanostructure directly. The electron microscopy results suggested that more than 90% of the obtained hollow nanospheres were in the range 100–200 nm, and the thickness was about 20 nm. In addition, the BET measurement indicated that the specific surface area of the Li2NH hollow nanospheres was 79 m2/g. Because of its short diffusion distance and large specific surface area, the novel structure enhanced the hydrogen storage kinetics of Li2NH dramatically. It was found that the obtained sample could absorb 6.0 wt % hydrogen in 1 min at 473 K, and the desorption temperature decreased about 115 K compared with the bulk sample. In addition, the effect of novel structure on hydrogen storage kinetics was discussed.