Effect of Annealing Time on the Structure and Electrochemical Properties of LA0.70MG0.30NI2.45CO0.75AL0.30 Hydrogen Stora Ge Alloy

Abstract

The as-cast alloy with the composition of La 0.70 Ni 2.45 Co 0.75 Al 0.30 was prepared by melting. La-Mg-Ni-based La 0.70 Mg 0.3 Ni 2.45 Co 0.75 Al 0.30 hydrogen storage alloy has been synthesized by milling blending of the as-cast alloy andelemental Mg, followed by an annealing for x (x= 2, 4, 6 and 8 h) at 600℃. The effect of annealing time on the structure and electrochemical properties of La 0.70 Mg 0.3 Ni 2.45 Co 0.75 Al 0.30 hydrogen storage alloy was investigated. The results showed that the La 0.70 Mg 0.3 Ni 2.45 Co 0.75 Al 0.30 alloys contain the LaNi 5 and (La,Mg) 2 Ni 7. The maximum discharge capacity of the La 0.70 Mg 0.3 Ni 2.45 Co 0.75 Al 0.30 alloy increases first and then decreases with increasing annealing time. The maximum discharge capacity of alloy reaches the optimumwhen x is 4 h. The cyclic stability of the La 0.70 Mg 0.3 Ni 2.45 Co 0.75 Al 0.30 alloy for a longer annealing time is better than that of the alloy for a shorter annealing time.