Structural and electrochemical hydrogen storage properties of MgTiNix (x = 0.1, 0.5, 1, 2) alloys prepared by ball milling

• A series of MgTiNix (x = 0.1, 0.5, 1, 2) alloys have been prepared by high-energy ball milling.
• The phase transformations and electrochemical properties of studied materials have been characterized and analyzed.
• The influence of Ni content on the structure and electrochemical behavior of Mg–Ti–Ni ternary alloys have been discussed.

A series of Mg–Ti–Ni alloys with different Ni content was prepared by mechanical alloying using a planetary high-energy ball mill. The structural transformation was characterized by XRD and SEM. It indicated that the addition of 10 at% Ni did not hinder the amorphization of MgTi BCC phase. After 40 h of milling, the alloys of MgTiNi and MgTiNi2 mainly consisted of the mixture of TiNi + MgNi + Mg2Ni and TiNi + TiNi3 + MgNix (x > 1), respectively. Their discharge capacities were investigated by electrochemical measurements at galvanostatic conditions. It was shown that all of the studied samples possessed good cycling performance. Among them, MgTiNi showed the highest discharge capacity. In the ternary alloys with the same atom ratio of Ti and Mg, the number of activation cycles decreased with increasing the Ni content.