Wk. Hu et al., STUDIES ON MULTICOMPONENT RARE EARTH-BASED HYDROGEN STORAGE ALLOYS WITH SMALL AMOUNTS OF BORON, Journal of alloys and compounds, 280(1-2), 1998, pp. 314-320
Several multi-component him-based alloys were prepared by the are melt
ing method and the electrochemical properties such as capacity, cyclin
g stability and rate capability were examined in 6 N KOH at 30 degrees
C. Small amounts of boron in MPI alloys noticeably improved the cycli
ng stability of the alloy electrodes regardless of a modest decrease i
n capacity due to the contraction in unit cell volume. The optimum all
oy composition from our experimental results would be of MmNi(3.65)Co(
0.62)Mn(0.36)Al(0.27)B(0.1). The initial capacity of this alloy was ab
out 286 mA h g(-1) at the 0.2 C rate. The capacity decay after 500 cyc
les at the 1.0 C rate was 25.7%. After annealing treatments, the alloy
showed better cycling stability with a capacity decay of 16.6% after
500 cycles. In addition, the mechanism of hydriding-dehydriding on MH
electrodes, and the relationship between the rate capability and the c
harge-transfer resistance as well as the polarization resistance of al
loy electrodes were also discussed. (C) 1998 Elsevier Science S.A. All
rights reserved.