Effects of Substitution of Al and Bi for Ni on Structure and Hydrogen Storage Properties of LaNi 4.7-x Al 0.3 Bi x (x=0.1, 0.2, 0.3) Alloy

In this research, the effects of Al and Bi substitution for Ni on the microstructure and hydrogen absorption/desorption properties of LaNi 4.7- x Al 0.3 Bi x ( x =0.1, 0.2, 0.3) alloys were investigated. The results showed that substituting Ni with Al led to a desirable decrease in absorption/desorption plateau pressure as well as to hysteresis without a reduction in hydrogen capacity. However, Bi substitution reduced the hydrogen capacity and increased the absorption/desorption plateau pressure of the samples. The formation of the (Al,Ni) intermetallic and Bi phases at grain boundaries was found to be the main reason for the changes in hydrogen storage properties.