Electrochemical properties of the ball-milled La_(1.8)Ca_(0.2)Mg_(14)Ni_3 + xwt percent Ni composites (x=0, 50, 100 and 200)

摘要

The electrochemical characteristics of the as-cast and ball-milled La_2Mg_(17) type alloy La_(1.8)Ca_(0.2)Mg_(14)Ni_3 +xwt percent Ni (x=0, 50, 100 and 200) were investigated. After 50 h ball-milling the amorphous La_(1.8)Ca_(0.2)Mg_(14)Ni_3 + 100 wt percent Ni composite exhibited a large discharge capacity of 1004 mAh g (La_(1.8)Ca_(0.2)Mg_(14)Ni_3)~(-1) at 298 K. Compared with the as-cast La_(1.8)Ca_(0.2)Mg_(14)Ni_3 alloy, the remarkable improvement in electrochemical capacity of the ball-milled composite is due to the formation of an amorphous composite. The addition of Ni is an important factor for the earlier formation of an amorphous alloy. The cycling degradation of the composite is influenced by the degree of amorphorization and the amount of Ni added.