Electrochemical properties of the Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 alloy mixed with Ni powder

Composites of Mm_0.3Ml_0.7Ni_3.55Co_0.75Mn_0.4Al_0.3 alloy and Ni powders were mechanically synthesized and electrochemically tested in 6 M KOH electrolyte. In this work, the electrochemical properties of the alloys were greatly improved by mixing them with Ni, which plays a corrosion-resistance role in the alkali electrolyte and helps electron conduction. It has been shown that the numbers of activation cycles decreased compared with the alloys without Ni powder. All the alloys were activated after the second cycle. Improvements of the maximum discharge capacities were also found in this work. A maximum discharge capacity of 358 mAh g⁻¹ was measured in the Mm_0.3Ml_0.7Ni_3.55Co_0.75Mn_0.4Al_0.3 + 250 wt.% Ni composite. In addition to that, adding Ni was found to enhance the high-rate discharge ability of the alloys, which appear to be good candidates for the realization of MH battery electrodes.