Microstructure and electrochemical properties of Ti-containing AB2 type hydrogen storage electrode alloy

The microstructure and electrochemical properties variation of alloy Zr(MnVNi)2 after Ti substitution for Zr was investigated. The microstructures of Zr1−xTix(MnVNi)2 (x=0, 0.5) alloys were determined with X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution electron microscopy (HREM) and energy dispersive spectrum (EDS) analysis. The systematic structural analysis shows that there are two phases in the Ti-substituted alloy Zr0.5Ti0.5(MnVNi)2, the C14 Laves and the Ti containing “premartensite” R phase, Ti0.8Zr0.2Ni. The variation in electrochemical properties of the alloy Zr(MnVNi)2 after partial Ti substitution can be attributed to the Ti substitution for some Zr sites in C14 Laves phase, the formation of Ti0.8Zr0.2Ni R-phase and the disappearance of Zr–Ni binaries.