The effects of substitution of Co for Ni on the cycling stability of Ti

0.8

Zr

0.2

V

2.7

Mn

0.5

-Cr

0.6

Ni

1.25-x

Co

x

Fe

0.2

(x=0.00 - 0.20)hydrogen storage alloys were investigated

and its intrinsic/extrinsic degradation mechanism was analyzed. The results show that the cycling stability of this type of alloy strengthens firstly and then weakens with increasing x from 0.00 to 0.20. Furthermore

the dissolution amount of the hydrogen absorbing elements(Ti and V)in KOH solution decreases firstly and then increases with increasing Co content after the same charge/discharge cycles

and the pulverization of the alloy particles and the deterioration of the electrode s

urface are suppressed with increasing x value.