Development of Catalyst-Enhanced Sodium Alanate as an Advanced Hydrogen-Storage Material for Mobile Applications

As a prototypical high-capacity complex hydride, sodium alanate (NaAlH4) has attracted significant attention because of its favorable thermodynamics and the potential low cost of its raw materials (NaH and Al). However, a high desorption temperature and slow kinetics preclude its practical use, particularly in mobile applications. The introduction of appropriate catalysts has been demonstrated to reduce the operating temperature and to improve the reversibility of hydrogen storage in NaAlH4 effectively. In this Review, we survey the development of various catalytic additives and their effects on the hydrogen-storage behavior of NaAlH4. First, the basic physical and chemical characteristics of NaAlH4 and its catalyst-doping methods are briefly summarized. Then, the catalytically enhanced hydrogen-storage properties and the corresponding mechanistic understanding are highlighted. Finally, the remaining challenges and the directions of future research efforts are discussed.