Preparation and electrochemical properties of some (Sc1-xTix)Ni alloys

A series of (Sc1-xTix)Ni alloys and their hydrides (Sc1-xTix)NiHy, where x=0, 0.1, 0.3, 0.5, and y=2.9, 2.58, 2.23 and 1.55, have been prepared. The ability to store hydrogen gradually decreases with increasing Ti content in line with the reduction of the unit cell volume from 32.16 ?3 for ScNi to 29.68 ?3 for (Sc0.5Ti0.5)Ni. The electrochemical discharge capacity, however, varies in a more complex manner with (Sc0.7Ti0.3)Ni composition displaying the highest value of 231 mAh/g. The discharge capacity losses after 10 electrochemical charge–discharge cycles also vary non-linearly between 46% for (Sc0.9Ti0.1)Ni and 5% for (Sc0.5Ti0.5)Ni.