Structural and Hydrogen Storage Properties Of Mg-x Wt% ZrCrMn Composites

¹Centre for Non-Conventional Energy Resources, University of Rajasthan, Jaipur, India

²Institute for Advanced Materials Research, Hiroshima University, Higashi-Hiroshima 739-8530, Japan

³ENEA-IDROCOMB, C.R. Casaccia, Via Anguillarese 301, 00060 S. Maria di Galeria, Rome, Italy

Adv. Mater. Lett., 2014, 5 (12), pp 692-698

DOI: 10.5185/amlett.2014.7588

Publication Date (Web): Dec 02, 2014

Copyright © IAAM-VBRI Press

E-mail: ankur.j.ankur@gmail.com

Abstract

Magnesium hydride is a promising material for hydrogen storage due to its high storage capacity i.e.7.6wt%. But its high stability i.e. high desorption temperature (~350? ^oC) limits its practical application towards hydrogen economy. Moreover the kinetics is also too slow even at high temperatures. Composite formation with Zr based laves phase alloys, especially ZrCr₂ family, is an effective method to improve the hydriding properties of MgH₂. This work presents the synthesis, structural, morphological, and hydrogenation properties of Mg-x wt% ZrCrMn composites. Both phases i.e. Mg & ZrCrMn remain their presence after milling and several hydriding cycles as well. SEM results suggest the homogeneous distribution of alloy particles on Mg matrix. Pressure composition temperature (PCT) analysis shows a reduction in desorption temperature down to 250^oC for these composites. TG experiments suggest a total hydrogen capacity of 5.9% and 4.35% for x =25, 50 in Mg-x wt% ZrCrMn composites respectively. The enthalpy of hydride formation is also calculated using Van’t Hoff plots, which is found similar to the parent material i.e. MgH2. A remarkable enhancement in the kinetics of hydrogen absorption / desorption is reported here by forming these composites.

Keywords

Hydrogen storage, magnesium, ball milling, kinetics, X-ray diffraction, microstructures