Phase-structural characteristics of (Ti1-xZrx)(4)Ni2O0.3 alloys and their hydrogen gas and electrochemical absorption-desorption properties

X-ray powder diffraction measurements of (Ti1-xZrx)(4)Ni2O0.3 (x = 0, 0.25, 0.5, 0.75) alloys vacuum annealed at 1000 degreesC exhibited the formation of the eta -phase with filled the Ti,Ni-type structure in all samples. Hyd rogen absorption studies revealed that Zr-containing alloys have higher hyd rogen storage capacities (H/M similar to1.25) compared to Ti4Ni2O0.3 (H/M = 0.9). Desorption measurements have shown that the hydrogen was evacuated i n vacuum mainly at 120-600 degreesC and the stability of hydrides increased following the rise of the Zr-content. Electrochemical charge-discharge cyc ling of (Ti1-xZrx)(4)Ni2Ox revealed substantial dependence of capacity and cycle-life of these materials on the Ti/Zr ratio, oxygen content and electr ode preparation. (C) 2001 Elsevier Science B.V. All rights reserved.