Electrochemical properties of Ti-based Quasicrystal and ZrV2 Laves phase alloy composite materials as negative electrode for Ni–MH secondly batteries

The Ti1.4V0.6Ni alloy ribbon is prepared by arc melting and subsequent melt-spinning technique. The ZrV2 alloy is prepared by arc melting and annealing at 1250 k for 80 h. The structure and electrochemical properties of the Ti1.4V0.6Ni and their ball-milled composites with annealed ZrV2 are investigated. Phase structure investigations of the composites show that alloys mainly consist of the icosahedral quasicrystal (I-phase), C14 Laves phase with a hexagonal structure, C15 Laves phase with cubic structure, V-based solid solution phase with BCC structure and face centered cubic (FCC) phase with Ti2Ni-type structure. The negative electrode made by composite alloys has a maximum discharge capacity of 360.3 mAh/g at a current density of 30 mA/g and a high rate discharge ability of 82.7% at 240 mA/g. The cyclic stability of the negative electrode made of Ti1.4V0.6Ni and annealed ZrV2 composite is higher than that of Ti1.4V0.6Ni. The mechanism for the capacity loss of the alloy electrodes during charge and discharge cycling has been studied in this paper.

► The composite alloys contain C15 Laves.
► The cyclic stability of the composite alloy electrodes is greatly improved.
► The annealed ZrV2 alloy plays a synergistic effect in electrochemical reaction kinetics.