Relationship between cooling rate and electrochemical performance of melt-spun AB5 alloy

The crystal structure and electrochemical properties of Ml(NiCoMnAl) 5 alloys prepared by both rapid solidification (melt spinning) and conventional cast methods were systematically investigated. The results show that the charging/discharging cycle life of rapidly solidified alloy is greatly improved, and the mean capacity attenuation rate of the rapidly solidified alloy is 13 times lower than that of the as cast alloy after 600 cycles. All of the melt spun alloys have almost the same discharge capacity as the as cast alloy except for the alloy with the cooling rate of 1.8×10 5 K/s, which has the largest discharge capacity of 310 mAh/g. The melt spun alloys need longer activation process than the conventional cast alloy. High rate dischargeability becomes poorer as the cooling rate increases in solidification also. Obviously improved electrochemical properties of the melt spun alloy are closely related to its fine grain, elimination of secondary phase AlNi 3 and uniform composition distribution.