Electrochemical properties of an amorphous 2Mg + 3d alloys doped by nickel atoms (3d = Fe, Co, Ni, Cu)

Amorphous 2Mg + 3d/x wt% Ni materials were prepared by mechanical alloying (MA) of Mg and 3d elemental powders (3d = Fe, Co, Ni, Cu; 0 ≤ x ≤ 200) under high purity argon atmosphere. The effect of the Ni addition on the electrochemical properties of the synthesized nanostructured alloys was investigated in details. The results show that the 48 h mechanically alloyed 2Mg-3d nickel-free mixtures still maintains Mg and 3d elemental phases. The nickel addition is advantageous for the formation of Mg-3d amorphous structures and for the improvement of the electrochemical properties of the studied alloys. With increasing nickel content, the discharge capacity of the 2Mg-3d alloys first increases and then decreases reaching a maximum of 155, 93, 175 and 130 mAh g−1 at x = 100 for 3d = Fe, Co, Ni and Cu, respectively. Additionally, for 2Mg + Ni/Ni with increasing nickel, the discharge capacity increases from 90 mAh g−1 (x = 0) to 175 mAh g−1 (x = 100) and then decreases to 64 mAh g−1 (x = 200). For all 2Mg + 3d synthesized materials, mechanical alloying with nickel effectively reduced the degradation rate of the studied electrodes. This result indicates that the nickel content does help to inhibit the corrosion of the alloy electrode in the KOH solution.