Effect of annealing treatment on hydrogen storage properties of La-Ti-Mg-Ni-based alloy

The present study dealt with investigations on the effects of annealing on the hydrogen storage properties of La1.6Ti0.4MgNi9 alloys. The experimental alloys were prepared by magnetic levitation melting followed by annealing treatment. For La1.6Ti0.4MgNi9 alloys, LaNi5, LaNi3 and LaMg2Ni9 were the main phases, Ti2Ni phase appeared at 900 °C. Annealing not only enhanced the maximum and effective hydrogen storage capacity, improved the hydrogen absorption/desorption kinetics, but also increased the discharge capacity. The cyclic stability had been improved markedly by annealing, e.g., when the discharge capacity reduced to 60% of maximum discharge capacity, the charge/discharge cycles increased from 66 (as-cast) to 89 (annealed at 800 °C) and 127 times (annealed at 900 °C). La1.6Ti0.4MgNi9 alloy annealed at 900 °C exhibited better electrochemical properties compared to the other two alloy electrodes.