Abstract: The effects of partial substitution of Mg, Ni in Mg-based alloy on its electrochemical and hydrogen storage properties were investigated. Mg_0.9Ti_0.1Ni_0.9X_0.1(X=Mn, Zn, Co, Fe) quaternary alloys were synthesized by mechanical alloying(MA) on the basis of the ternary Mg_0.9Ti_0.1Ni alloy. The X-ray diffraction showed that the X partial substitution of Ni promoted the amorphous process of Mg_0.9Ti_0.1Ni alloy. It was found that the Co-substituted and Fe-substituted alloys showed enhanced discharge capacities. The cycle life of the alloys was improved with the addition of Mn and Zn, especially Mg_0.9Ti_0.1Ni_0.9Zn_0.1 alloy remained to keep a higher discharge capacity after the 10 cycles of charge and discharge. The hydrogen content in Mg_0.9Ti_0.1Ni_0.9Co_0.1 alloy is higher than that in Mg_0.9Ti_0.1Ni} alloy, which is in agreement with the result measured by the electrochemistry.

Key words: Mg-based hydrogen storage alloys, Mechanical alloying method, Amorphous state, {Electrode}