Structure Analysis of Mg-Fe-Graphite/Graphene compounds

Abstract

It is investigated that the structure of Magnesium (Mg)-based compound containing Fe and graphene (GN) for Mg-based hydrogen storage material, which is one of the most prospective hydrogen storage materials because Mg possesses a larger hydrogen storage capacity (7.6 wt.%). The high dehydrogenation temperature of Magnesium hydride (MgH2) (approximately 450 ℃) should be reduced for a wide range of applications and one of the solutions would be to compound Fe and/or graphene into Mg due to decreasing the binding energy of hydrogen and Mg. Firstly, we prepared less-defected graphene by Salt-assisted Milling - Liquid Phase Exfoliation method (SM-LPE) method and evaluated the number of layers and the crystallinity with Raman spectroscopy. We estimated the GN consists of a single and/or a few layers and has high crystallinity with few defects. Secondly, we prepared the five different compounds of Mg, Fe, Graphite (Gr), and Graphene (GN) by high-energy ball milling and the different milling time. With regard to the compounds, a large amount of amorphous powder was recovered in all of the compounds to which Gr/GN was only added. In terms of the order of addition of Gr/GN, it was confirmed that the Gr/GN adhered to the Mg surface by being added at later milling, and in particular the GN was distributed throughout the sample as nano-particles.