Effects of Pd addition on electrochemical properties of MgNi
Journal of Alloys and Compounds, 372 (2004) 251-258
Tiejun Ma, Yuji Hatano, Takayuki Abe, Kuniaki Watanabe
Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan
Abstract
Two kinds of Pd-modified MgNi were prepared and effects of Pd addition on the electrochemical properties of MgNi were investigated. Sample I was prepared by ball-milling amorphous MgNi with Pd (1, 6 and 10 mol%) for 10 min, 2 and 10h, and sample II was obtained by ball-milling Mg2Ni and Ni with 10 mol% Pd for 80h. The effects of Pd-modification for sample I depended on both Pd ratio and time of ball-milling. During the ball-milling, Pd became amorphous and distributed rather uniformly not only on the surface but also in the bulk of MgNi powder. At 6 and 10 mol% Pd, the degradation of discharge capacity of MgNi was significantly decreased. As for sample II, the cycle life was remarkably improved by the Pd-modification. Analyses of the roles of Pd on the behavior of MgNi showed that the improvements of MgNi properties by both Pd-modifications were not due to the increase in hydrogen absorption ability but caused by the suppression of Mg(OH)2 formation.