Hydrogen absorption behavior of multicomponent zirconium based AB2 alloys with different chromium-vanadium ratio

Recent developments on new electrode materials for nickel-metal hydride batteries include Laves phases based on ZrCr2 with multiple substitutions to improve the electrode performance. In this work, results on the hydrogen absorption behavior of the Zr0.9Ti0.1NiMn0.5CrxV0.5-x alloy (with 0≤x≤0.5) obtained by volumetric and electrochemical techniques are presented. The structural and morphological characterization of the alloy is also studied by X-ray powder diffractometry (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The (PCT) curves show a high hydrogen storage capacity expressed as hydrogen atoms per formula unit (H/F.U.∼3.6), and a steep slope rather than a horizontal plateau corresponding to the two-phase equilibrium. Electrode activation was achieved by voltammetric cycling between preset potentials in alkaline solution. Discharge capacities of about 340 mAh/g are found for high Cr/V content ratios, whereas the high-rate dischargeability significantly decreases on increasing the Cr content in the alloy