<p>As a hydrogen storage material, both AlH₃ and LiNH₂ possess a high hydrogen capacity. However, the dehydrogenated AlH₃ can hardly absorb hydrogen under normal conditions, while LiNH₂ will generate NH₃ rather than H₂ upon decomposition. In this work, we report that the combination of AlH₃ and LiNH₂ through simple ball milling leads to partial reversibility of the AlH₃−LiNH₂ system and the suppression of NH₃ liberation. The negatively charged H^<i>δ</i>− in AlH₃ will react with the positively charged H^<i>δ</i>+ in LiNH₂ through a redox reaction to form Li₂NH, AlN, and H₂ at 120−170&#xa0;°C. After dehydrogenation at above 270&#xa0;°C, Li₃AlN₂ is generated, which is crucial for the reversibility of this system. The more the Li₃AlN₂ generated, the better the reversibility of this system. The dehydrogenation capacity of AlH₃ + 2LiNH₂ at the third cycle (3.0 wt%) is higher than that of AlH₃ + LiNH₂ (1.2 wt%) due to the generation of more Li₃AlN₂. The role of AlH₃/Al in the AlH₃−LiNH₂ system is to fix the nitrogen into the form of AlN and Li₃AlN₂ and thus suppress the liberation of NH₃. Therefore, the synergy of AlH₃ and LiNH₂ leads to the reversibility of the Li–Al–N–H system and the suppression of NH₃.</p> Graphical abstract <p></p>