Recent advances in liquid-phase chemical hydrogen storage

Exploring safe and efficient hydrogen storage materials has been one of the toughest challenges for the upcoming hydrogen economy. High capacity, mild dehydrogenation conditions and good stability at room temperature endow liquid-phase chemical hydrides the great potential to be utilized as the next generation of hydrogen storage medium. In this review, we will shed light on the recent advances in liquid chemical hydrides, including metal-boron hydrides, ammonia borane, formic acid, hydrazine hydrate and aromatic compounds. A special focus will be placed on the roles of catalysts in controlling dehydrogenation process of different liquid chemical hydrides as well as their synthetic strategies. Meanwhile, the recycling solutions of spent liquid chemical hydrides are also evaluated for developing the affordable and sustainable hydrogen storage systems to achieve the requirements for further industrial applications.