Improving hydrogen storage performance of Li-Mg-N-H system by adding niobium hydride

Hydrogen storage properties of 2LiNH(2)-MgH2-xNbH (x = 0 and 0.05) composites and the catalysis of NbH on hydrogen sorption reaction of the Li-Mg-N-H system were investigated. Hydrogen sorption properties of 2LiNH(2)-MgH2 system are effectively improved by adding NbH. Temperature programmed desorption results show the addition of NbH reduces the dehydriding onset temperature of 2LiNH(2)-MgH2 system by 21 K. Approximate 3.62 wt% hydrogen in 2LiNH(2)-MgH2-0.05NbH composite is released following a 500 min at 433 K, whereas the amount of hydrogen desorption is only similar to 3.16 wt% for the pristine system under the same condition. The sample with NbH exhibits higher dehydriding rate compared with the pristine one. Moreover, hydrogen absorption rate increases by adding NbH into the 2LiNH(2)-MgH2 system. Hydrogen absorption capacity of the samples with NbH is 3.23 wt% within 400 min, which is higher than that of pristine sample. Fine NbH particles homogeneously distribute in the 2LiNH(2)-MgH2-0.05NbH composite, and catalyze the hydrogen sorption reaction rather than reacts as a reactant into new compound.