Investigation into the thermal stability and decomposition processes in AlH3 and stearic acid-coated AlH3

Aluminium hydride (AlH 3 ), a promising metal-based hydrogen storage material, faces problems related to its relatively poor stability. In the paper, the thermal stability of stearic acid-coated AlH 3 (SA/AlH 3 ) and AlH 3 was compared by thermogravimetric analysis and minimum ignition temperature test, including pyrolysis and ignition stability. The decomposition temperature and apparent activation energy of SA/AlH 3 were higher than those of AlH 3 , indicating that the decomposition was more difficult. During pyrolysis, SA/AlH 3 demonstrated a higher minimum ignition temperature and a slower rate of potential energy decline, which indicated that the coating of SA had improved the thermal stability of AlH 3 . Reactive force field molecular dynamics simulation revealed the difference in pyrolysis behavior between AlH 3 and SA/AlH 3 . Small molecular products such as H 2 , H 2 O, CH 4 , C 2 H 4 , CO, and CO 2 were generated, further generating clusters dominated by C-Al bonds. Improving the thermal stability of SA/AlH 3 coating is an important reference for the application of AlH 3 in energetic materials.