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