Synthesis and Hydrogen Sorption Characteristics of Mechanically Alloyed Mg(NixMn1-x)2 Intermetallics

TL;DR

This study synthesizes new Mg-Ni-Mn intermetallics via high energy ball milling and evaluates their potential for hydrogen storage, revealing temperature-dependent kinetics with faster processes at higher temperatures.

Contribution

It introduces a novel synthesis method for Mg-Ni-Mn intermetallics and provides detailed analysis of their hydrogen sorption properties.

Findings

Fast hydrogenation/dehydrogenation at 250-300°C

Slow hydrogenation at below 200°C

Dehydrogenation not achieved below 200°C

Abstract

New ternary Mg-Ni-Mn intermetallics have been successfully synthesized by High Energy Ball Milling (HEBM) and have been studied as possible materials for efficient hydrogen storage applications. The microstructures of the as-cast and milled alloys were characterized by means of X-ray Powder Diffraction (XRD) and Scanning Electron Microscopy (SEM) both prior and after the hydrogenation process, while the hydrogen storage characteristics (P-c-T) and the kinetics were measured by using a commercial and automatically controlled Sievert-type apparatus. The hydrogenation and dehydrogenation measurements were performed at four different temperatures 150-200-250-300oC and the results showed that the kinetics for both the hydrogenation and dehydrogenation process are very fast for operation temperatures 250 and 300oC, but for temperatures below 200oC the hydrogenation process becomes very slow and the dehydrogenation process cannot be achieved.