Hydrogen storage of Mg-Zn mixed metal borohydrides

On the basis of DFT results on the ideal amount of Zn required to dissolute into the alpha-phase of Mg(BH4)(2) (space group P6(1)22) and experimental results recently presented in the literature, mixtures of alpha-Mg(BH4)(2) and ZnCl2 have been prepared by ball-milling, reactive milling and cryo-milling in Mg:Zn starting ratios of 1:0.33, 1:0.2 and 1:0.1. Samples have been characterized with different experimental techniques (PXD, TGA, TPD with RGA and desorption kinetics in a Sieverts apparatus). All the as-milled samples exhibited a H-2 release beginning approximately at 125 degrees C, indicating a significant decrease in the decomposition temperature compared to pure Mg(BH4)(2). With the exception of the Mg(BH4)(2)-0.33ZnCl(2) sample ball-milled under 1 bar Ar for 3 h that showed a small B2H6 release around 120 degrees C, all samples are free of B2H6 emissions. Results from desorption kinetics at 195 degrees C suggest a strong relation between the amount of ZnCl2 in the starting mixture and the weight loss. (C) 2014 Published by Elsevier B.V.