Effects of annealing on Zr8Ni19X2 (XÂ =Â Ni, Mg, Al, Sc, V, Mn, Co, Sn, La, and Hf): Hydrogen storage and electrochemical properties

► The annealing effects on the modified Zr8Ni21 alloys were studied. ► The modifying elements include Ni, Mg, Al, Sc, V, Mn, Co, Sn, La, and Hf. ► Both gaseous phase and electrochemical properties are reported. ► Annealing raises the maximum hydrogen storage for alloys with tetragonal Zr7Ni10. ► Zr8Ni19Hf2 alloy shows the best overall electrochemical properties in this study.