Enhanced hydrogen desorption kinetics and cycle durability of amorphous TiMgVNi3-doped MgH2

Abstract

MgH2 is considered as a promising hydrogen storage material for on-board applications. In order to improve hydrogen storage properties of MgH2, the amorphous TiMgVNi3-doped MgH2 is prepared by ball milling under hydrogen atmosphere. It is found that the catalytic (Ti,V)H2 and Mg2NiH4 nanoparticles are in situ formed after activation. As a result, the amorphous TiMgVNi3-doped MgH2 exhibits enhanced dehydrogenation kinetics (the activation energy for hydrogen desorption is 94.4 kJ mol−1 H2) and superior cycle durability (the capacity retention rate is up to 92% after 50 cycles). These results demonstrate that the in situ formation of highly dispersed catalytic nanoparticles from an amorphous phase is an effective pathway to enhance hydrogen storage properties of MgH2.