TiMn2-based alloys as high hydrogen storage materials

A series of TiMn multicomponent alloys based on the composition TiMn2 with high hydrogen storage capacity were investigated. It is found that the alloy Ti0.8Zr0.3Mn1.4Mo0.1V0.2Cr0.2 has a maximum hydrogen capacity of 3.4 H/M (mol H/mol alloy), theoretical electrochemical capacity of 560 mAh g−1, exhibits a plateau pressure range between 0.006 and 0.01 MPa at 293 K. Addition of the elements Si and Al in a four component alloy causes the hydrogen storage capacity to decrease and plateau pressure to increase. Addition of a small amount of Mo increases hydrogen storage capacity. The substitution of V for Mn lowers the plateau pressure dramatically. The phase composition and microstructure of Ti0.8Zr0.3Mn1.4Mo0.1 V0.2Cr0.2, which is one of the highest capacity TiMn2-based alloys, has been studied by X-ray diffraction, optical microscopy and scanning electron microscopy.