AlH₃ is a metastable hydride with a high hydrogen density of 10.1 wt% and it can release hydrogen at a low temperature of 150–200 °C. Many additives (e.g., NbF₅, TiF₃, etc.) introduced by ball milling can significantly reduce the decomposition temperature of AlH₃, but often simultaneously decrease the available hydrogen capacity. In this work, TiB₂ was introduced by ball milling to improve the decomposition performance of AlH₃. AlH₃ + x wt% TiB₂ (x = 2.5, 5, 7.5, 10) composites were prepared by ball milling, and the milling conditions were optimized. It was shown that the decomposition performance of the AlH₃ + 2.5 wt% TiB₂ ball milled at 225 rpm for 108 min is the best. The onset decomposition temperature is 78 °C, which is 60 °C lower than that of pure AlH₃. The decomposition is terminated at 130 °C with 8.5 wt% of hydrogen is obtained. In addition, 5.3 wt% of hydrogen can be released within 200 min at constantly 80 °C. Under the same conditions, ball-milled AlH₃ can hardly release any hydrogen. The activation energy calculated by the Kissinger's method is 86 kJ mol⁻¹, which was 28 kJ mol⁻¹ lower than that of ball-milled AlH₃. Catalytic mechanism study reveals that the Al₂O₃ layers on the surface of AlH₃ will interact with TiB₂ to form Al–Ti–B solid solution, resulting in lattice distortion. Through lattice activation, the decomposition kinetics of AlH₃ is improved. This work provides an efficient strategy to achieve both high hydrogen capacity and low decomposition temperature of metastable AlH₃ by proper ball milling with metal borides.

AlH ₃是一种亚稳态氢化物，氢密度高达10.1 wt%，可在150-200 °C的低温下释放氢气。通过球磨引入的许多添加剂（例如，NbF ₅、TiF _{3等）可以显着降低AlH 3}的分解温度，但通常同时降低可用的氢容量。在这项工作中，通过球磨引入TiB _{2以提高AlH 3}的分解性能。AlH ₃  +  x wt% TiB ₂ ( x = 2.5, 5, 7.5, 10) 采用球磨法制备复合材料，并优化了球磨条件。结果表明，AlH ₃ + 2.5 wt% TiB ₂在225 rpm下球磨108 min的分解性能最好。起始分解温度为78℃，比纯AlH ₃低60℃ 。分解在 130 °C 时终止，得到 8.5 wt% 的氢气。此外，在 80 °C 恒定条件下，200 分钟内可以释放出 5.3 wt% 的氢气。在相同条件下，球磨AlH ₃几乎不释放氢气。基辛格法计算的活化能为86 kJ mol ^-1，为28 kJ mol ^-1低于球磨AlH ₃。催化机理研究表明， AlH ₃表面的Al ₂ O ₃层会与TiB ₂相互作用形成Al-Ti-B固溶体，导致晶格畸变。通过晶格活化，改善了AlH ₃的分解动力学。这项工作提供了一种有效的策略，通过与金属硼化物进行适当的球磨来实现亚稳态 AlH ₃的高氢容量和低分解温度。