This paper presents a novel surface coating to resolve the serviceability, stability, compatibility, and dehydrogenation of aluminum hydride (alane) using liquid carbon dioxide as an anti-solvent, dispersant, drying medium, and inert atmosphere. The coated alane sample was characterized by SEM, XPS, XRD, and FT-IR spectroscopy. The coating agent was uniformly applied on the surface of alane and the crystalline phase remained unchanged. The alane molecules became more stable after coating. The thermal stability of alane before and after coating was analyzed by DSC. The enthalpy of the coated alane increased under different heating rates, indicating increased thermal stability. The lower electric spark sensitivity of the coated alane showed improved serviceability and stability. The method developed in this study may be suitable for coating other hydrogen storage and energetic materials.