Electrochemical properties of CeMg11Ni+x%Ni composites(x=0, 50, 100 and 200) prepared by ball-milling
(Department of Materials Science and Engineering, Zhejiang University,
Hangzhou 310027, China)
Hangzhou 310027, China)
Abstract: The electrochemical properties of the as-cast CeMg11Ni and ball-milled CeMg11Ni+x%Ni(x=0, 50, 100 and 200, mass fraction) composites were investigated. The results show that homogeneous amorphous phase of CeMg11Ni+x%Ni composite can be obtained by ball-milling, and discharge capacity of the ball-milled CeMg11Ni+x%Ni composites differs greatly depending on the amount of Ni introduced during milling. The CeMg11Ni+200%Ni composite after 90h ball-milling was found to exhibit a large discharge capacity of about 1012mAh/g at 303K, and it also shows better charge-discharge cycling stability than those with lower Ni content. This remarkable improvement in electrochemical properties of the ball-milled composites seems to be attributed to the formation of an amorphous composite as well as the improvement of the surface state of the ball-milled particles.
Key words: hydrogen storage alloy; CeMg11Ni; amorphous phase; electrochemical properties