Charge/discharge performances and corrosion behaviors of Ti ₂Ni hydrogen storage alloy

An amorphous Ti ₂Ni alloy was prepared by ball milling of a crystalline Ti ₂Ni alloy. XRD, charge and discharge testing, and anodic polarization curve were carried out and investigated to study the charge/discharge performances and the corrosion behaviors of Ti ₂Ni hydrogen storage alloy with different structures. Results show that the crystalline alloy has a charge capacity of 480 mAh/g at first cycle, while its discharge capacity is only a half of the charge capacity. A large amount of irreversible hydride is formed in the bulk alloy. However, there is no evident formation of the irreversible hydride in the subsequent cycle. The amorphous phase can restrain the formation of the irreversible hydride. And a elastic deformation occurs during the hydrogen absorption/desorption process. Moreover, the amorphous structure makes the alloy corrosion potential increasing and the alloy corrosion current density decreasing, resulting in an significant improvement of corrosion resistance of the alloy. Copyright