Highly ameliorated gaseous and electrochemical hydrogen storage kinetics of nanocrystalline and amorphous CeMg12-type alloys by mechanical milling

Abstract An attempt that effectively advances the quantity of hydrogen storage for CeMg 12 -type alloys was adopting a method of partial substitution of Mg in alloy by Ni. It is also employing mechanical ball-milling technology to prepare the nanocrystalline and amorphous CeMg 11 Ni +  x wt.% Ni ( x  = 100, 200) alloys. And these two factors, Ni content after replacement as well as ball grinding time, affecting the structures and hydrogen storage dynamics belonging experimental alloys were studied systematically. Thereinto, characterization analysis on structures was using XRD, SEM and HRTEM. Then, the test of gaseous hydrogen storage performance was carried out through Sievert device as well as differential scanning calorimeter (DSC) that connected with H 2 detector. Besides, Arrhenius and Kissinger equations were served as a convenient method for calculating the hydrogen desorption activation energy of alloys. Finally, it can adopt the automatic galvanostatic system to measure the electrochemical hydrogen storage performance. It is shown that, for experimental alloys, the more Ni content shows beneficial on the formation of glass, meanwhile, it also strikingly ameliorates both gaseous and electrochemical hydrogen storage dynamics properties. In addition, milling time varying brings a very large impact upon hydrogen storage properties of alloys. When the ball-grinding time is constantly changing, the gaseous hydrogen absorption capacity, gaseous hydriding rate as well as high-rate discharge ability (HRD) of alloys are able to appear the maximum values respectively. However, following the prolongation of milling time, both electrochemical discharge capacity and gaseous dehydrogenating rate raise all the time. The increase in Ni content and the prolongation of milling time can both enhance the gaseous hydrogen storage dynamics of alloys, inferring that their essence all can be attributed to the reduction of the activation energy of hydrogen desorption.