The effect of Ni content on the phase structures and electrochemical properties of V2.1TiNix (x=0.1-0.9) hydrogen storage alloys

The phase structures and electrochemical properties Of V2.1TiNix (x = 0.1, 0.3, 0.5, 0.7, 0.9) alloys were investigated by the general electrochemical techniques and X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectrometer and emission spectrochemical analysis. Nickel added into V-2.1 Ti alloy plays a key role in the performance of the new alloys, due to the formation of a continuous TiNi-based secondary phase in the form of a three-dimensional network around the main phase. Though the hydrogen absorbed by the alloy reduces with the increase of nickel content, the actual electrochemical discharge capacity and the high-rate discharge capability are improved noticeably. Among the studied alloys, V2.1TiNi0.5 with a good combination of the main phase and the secondary phase has the best overall electrochemical performance. (C) 2002 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.