High-pressure DSC study of the hydrogen sorption behaviour of MgH2 and MgH2/graphite processed by reactive mechanical alloying

G. URRETAVIZCAYA; V. FUSTER; F.J. CASTRO

Moscú

Simposio; International Symposium "Metal-Hydrogen Systems. Fundamentals and Applications"; 2010

Chemistry Department, Lomonosov Moscow State University

The study of the hydrogen absorption and desorption properties of Mg and Mg/graphite materials by high-pressure DSC is reported. The materials were sinthesized by reactive mechanical alloying magnesium and graphite under hydrogen atmosphere [1]. Kinetics of MgH2 with graphite is better than the absorption and desorption rates of MgH2 synthesized without additive. Additionally, the catalytic effect of graphite is more effective when the additive is uniformly distributed in the bulk, i.e., when graphite is incorporated from the beginning of the hydride synthesis by RMA. The high temperatures required during HPDSC runs favours sintering of magnesium and hence, a slight capacity decrease with cycling can be partially attributed to this effect. Additionally, some protection against oxidation is observed in graphite-containing samples. This protection is more effective when graphite is mainly located on the surface of the particles. References 1. V. Fuster, G. Urretavizcaya, F.J. Castro, J. Alloys Compd. 481 (2009) 673-680.