Hydrogen Storage in Li₃N:  Deactivation Caused by a High Dehydrogenation Temperature

As a potential candidate for hydrogen storage, Li 3 N can absorb more than 9 wt % hydrogen. However, because of its incomplete dehydrogenation at a temperature of 280 °C, only about 5.5 wt % reversible hydrogen capacity could be reached. Although by increasing the temperature one can enhance dehydrogenation, this paper demonstrates that dehydrogenation of hydrogenated Li 3 N at the high temperature of 400 °C is followed by a very low (0.4 wt %) rehydrogenation capacity. Furthermore, scanning electron microscopy, Brunauer−Emmett−Teller surface area, and X-ray powder diffraction measurements have shown that both the sintering and the lattice structure change of Li 2 NH, which is a product of hydrogenation, might be responsible for such a major deactivation.