Near Ambient Condition Hydrogen Storage in a Synergized Tricomponent Hydride System

Abstract

Reversible hydrogen storage over hydrides of light elements (HLEs) under ambient condition has been pursued actively for nearly two decades. However, because of unfavorable thermodynamics and/or severe kinetic barrier of HLEs, limited progress has been made. Here, it is demonstrated that the interaction of LiBH4 with Mg(NH2)2 and LiH, three of the most investigated HLEs, can lead to a fully reversible dehydrogenation/rehydrogenation cycle at temperatures below 373 K. More importantly, with the desorption enthalpy of 24 kJ (mol H2)−1 the dehydrogenation process at 1.0 bar H2 is theoretically possible to be as low as 266 K. Characterization of this combination of HLEs shows that LiBH4 serves as a reagent complexing with intermediates and products of the dehydrogenation of Mg(NH2)2-LiH, and significantly alters the overall thermodynamic and kinetic properties of the system.