Preparation and electrode behavior of NdMgNi3.6Co0.4 hydrogen storage alloy

The crystal and amorphous NdMgNi3.6Co0.4 hydrogen storage alloys are prepared by ball milling of mixed powder of NdNi, Mg, Ni and following sintering of the pressed tablets of the milled powders at 1123 K for 8 h, and its electrode properties have been investigated by a simulated battery test at 293 K. XRD analysis shows that two phases (NdMgNi4 and Nd2Ni7) of the NdMgNi3.6Co0.4 alloy have been obtained under this sintering condition. The electrode properties tests indicate that the maximum discharge capacity of the alloy was increased by extending of ball-milling time from 0 to 50 h. An attenuation coefficience of k = 0.9552 has been observed for the electrode of 40 h milled NdMgNi3.6Co0.4. The maximum discharge capacity was 325 mAh/g. The electrode was activated after the second charging–discharging cycle and exhibited a plateau of discharge voltage for 4.5 h.