Transformation of Metallic Ti to TiH Phase in the Ti/MgH Composite and Its Influence on the Hydrogen Storage Behavior of MgH.

The current work explores the in-situ formation of TiH additive in a Ti/MgH nanocomposite system. Mild mechanical milling leaves Ti chemically unchanged, while formation of stable TiH occurs upon strong mechanical milling. TiH further transforms to TiH upon recycling the powder (dehydrogenation and subsequent hydrogenation) and lowers the activation energy of MgH to 89.4 kJ (mol H ) [E of as-received MgH is 153 kJ (mol H ) ]. This work also reiterates that metallic Ti additive mixed MgH requires strong mechanical milling for better H ab/de-sorption performance. The current observations support the view that lattice strain may be an important factor in the catalysis of additives incorporated MgH hydrogen storage systems.