Structure and electrochemical characteristics of CeMn1-xAl1-xNi2xCeMn1-xAl1-xNi2x (x=0.00x=0.00, 0.25, 0.50 and 0.75) alloys

The structure and electrochemical characteristics of Ni substitution for Mn and Al in AB2AB2-type CeMnAl intermetallic compounds are studied. XRD and SEM reveal that Ni partial substitution leads to a phase change of the alloys and new phase to be formed. The electrochemical activity of CeMn1-xAl1-xNi2xCeMn1-xAl1-xNi2x (x=0.00x=0.00, 0.25, 0.50 and 0.75) alloy is greatly improved and the discharge capacity can increase from 17.93mAhg-1 (x=0.00x=0.00) to 118.3mAhg-1 (x=0.75x=0.75) at 298 K and from 68.42mAhg-1 (x=0.00x=0.00) to 216.1mAhg-1 (x=0.75x=0.75) at 328 K, respectively. The electrochemical P–C–T curve shows that no hydrogen equilibrium pressure plateau is observed for CeMnAl alloy while the slope of the plateau becomes flatter and longer with increasing Ni content.