Dm. Kim et al., ELECTROCHEMICAL PROPERTIES OF OVER-STOICHIOMETRIC ZRMN1-XVXNI1.4-PHASE(Y ALLOYS WITH C15 LAVES), Journal of the Electrochemical Society, 145(1), 1998, pp. 93-98
Citations number
14
Categorie Soggetti
Electrochemistry,"Materials Science, Coatings & Films
The hydrogen storage performance and electrochemical properties of ZrM
n1-xVxNi1.4+y (x = 0.5, 0.7; y = 0.0, 0.2, 0.4, and 0.6) alloys, one t
ype with a high amount of manganese, i.e., x = 0.5, and the other with
a small amount of manganese, i.e., x = 0.7, were investigated. The re
lationship between discharge performance and alloy characteristics suc
h as crystallographic parameters, surface morphology, reaction surface
area, and exchange current density is also discussed. All of these al
loys were found to have mainly a C15-type Laves phase structure by x-r
ay diffraction analysis. The equilibrium hydrogen pressure of the allo
y increased as the amount of Ni increased in both types of alloys. In
the case of ZrMn0.5V0.5Ni1.4+y (y = 0.0, 0.2, 0.4, and 0.6) alloys, th
e discharge efficiency and the rate capability decreased as the amount
of Ni increased, while these values increased for the ZrMn0.3V0.7Ni1.
4+y (y = 0.0, 0.2, 0.4, and 0.6) alloys. After measuring the specific
reaction surface area and exchange current density to identify the rea
son why the electrode properties had a reverse tendency between the tw
o systems, we confirmed that for the ZrMn0.5V0.5Ni1.4+y (y = 0.0, 0.2,
0.4, and 0.6) alloys the major factor controlling the electrode prope
rties was the specific reaction surface area, not the exchange current
density, while, in the case of ZrMn0.3V0.7Ni1.4+y (y = 0.0, 0.2, 0.4,
and 0.6) alloys, mainly the exchange current density, not the specifi
c reaction surface area, controlled the electrode properties.