The hydrogen generation by reaction of borohydride of alkaline metals with water is actively investigated being oriented on development of hydrogen generators applicable for fuel cells. Considering hydrogen mass content and safety of its storage the most perspective compound is sodium borohydride.
The problem of stability of storage compounds appears in the projects on development of mobile hydrogen generators intended for transportation facilities. As in aqueous solutions there is a process of borohydride hydrolysis supplied by hydrogen generation, the problem of “storage stability” appears.
The results of experimental researches on stability of different forms of sodium borohydride (concentrated water solutions, slurry and solid forms) are reported. The influence of temperature and the concentrations of alkali and sodium borohydride on hydrolysis rate are investigated. Triple system derived from sodium borohydride crystalline hydrate by adding a small amount of alkali has much higher stability than triple systems in a solution.
Slurry and solid forms of sodium borohydride containing water are only relatively stable and at their storage it is necessary to take into account temperature regime and storage period. Waterless sodium borohydride is absolutely stable only within the range of practicable temperatures for considered applications.