Electrochemical hydrogen storage characteristics of Mg–Pd–Ni ternary alloys

Mg1−xPdxNi (x = 0.03, 0.05, 0.06, 0.07, 0.08, 0.10, 0.20) type alloys were synthesized by mechanical alloying and their electrochemical hydrogen storage characteristics were investigated. The XRD studies showed that Mg6Pd and Mg–Pd phases form in the high-Pd-containing alloys. The discharge capacities of the alloys increased sharply up to 15 h milling. Further increase up to 25 h did not cause change in the discharge capacities considerably. Among the Mg1−xPdxNi ternary alloys, Mg0.93Pd0.07Ni alloy was observed to exhibit the best charge/discharge cyclic performance. The hydrogen storage capacity of the high-Pd-containing alloys (Mg1−xPdxNi; x > 0.07) deteriorated as Pd content of the alloy increased. This observation was attributed to the Mg–Pd phase formations. According to the EIS experiments as Pd atomic ratio increased up to 0.07 the charge transfer resistances of the alloys decreased. Further increase in Pd atomic ratio, however, brought about the increase in the charge transfer resistances.