A process for enhancing the kinetics of hydrogenation/dehydrogenation of complex chemical hydrides using mechanomixing and/or mechanomilling. The mechanomixing makes hydrogenation/dehydrogenation of complex chemical hydrides reversible at much reduced temperature and pressure. The mechanomilling reduces particle size or grain size of the decomposition byproducts, further increasing surface area and intimate contact of the byproducts. In the process of the present invention, complex chemical hydrides can be utilized as a reversible hydrogen storage media for various applications such as transportation, including fuel cells. The process is simple and inexpensive.