Electrochemical behaviors of a V3TiNi0.5Hf0.24 alloy electrode during charge-discharge cycling

The electrochemical behaviors of a V3TiNi0.56Hf0.24 allay electrode during charge-discharge cycling have been studied. It is found that the main and s econdary phases of the V3TiNi0.56Hf0.24 alloy transform, respectively, to a dihydride of(V,M)H-2 and a C14 phase hydride of (Ti,Hf)(V,Ni)(2)H-x, durin g the charging process of the alloy electrode. When the electrode is discha rged to -0.7V versus Hg/HgO, both the reaction of (V,M)H-2 to (V,M)H and th e reaction of(Ti,Hf)(V,Ni)(2)H-x to (Ti,Hf)(V,Ni)(2) takes place. During fu rther discharging from -0.7 to -0.5 V,a strong dissolution reaction of vana dium and an incomplete dehydriding reaction of (V,M)H to beta (V,M) occurs simultaneously The strong dissolution of vanadium in KOH electrolyte soluti on seriously leads to the deterioration of the alloy. (C) 2001 Elsevier Sci ence B.V. All rights reserved.