from the conferences organized by TANGER Ltd. provisional website
A2B type Ti-Ni hydrogen storage alloy, which has also dissolved Zr in it, was synthesized directly from TiO2-ZrO2-NiO mixture in the molten CaCl2 electrolyte by the electro-deoxidation method at 900 C. Sintering of the oxide mixture at 1100 C for 2 h did not cause formation of any mixed type Ti-Zr-Ni oxide. Short time electro-deoxidation (< 5 h) yielded Ti3O5, CaTiO3, CaZrO3, Ni and Ti2O3 formations upon reduction of the sintered oxide mixture. Extension of the electro-deoxidation time up to 10 h caused disappearance of all these reduction products and there remained only TiO and Ti2Ni phases. Presence of TiO lasted about 15 h and then the target alloy structure with 100 % Ti2Ni phase was obtained with the maximum amount of dissolved Zr in it. The synthesized alloy was prepared as electrode and it was observed that it had maximum discharge capacity of 200 mA·h·g-1. The capacity retention rate of the electrode, however, was relatively low probably due to the barrier action of the formed oxide layer on the alloy surface. As the charge/discharge cycle increases the thickness of the oxide layer also increases and then the in/out diffusion of the elemental hydrogen becomes difficult.Keywords: Ti-Ni Alloys, electro-deoxidation; hydrogen storage; XRD
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