The mischmetal-based hydrogen storage alloys MlNi 3 . 8 Co 0 . 5 Mn 0 . 4 Al 0 . 3 Li x (Ml=La-rich mischmetal, 0<x<0.2) have been successfully synthesized by the diffusion method (DM). The properties of these alloys have been carefully investigated by means of XRD, PAT, PCT and the measurement of electrochemical capacity. Experimental results show that the Li-containing alloy, whose defects increase greatly, has excellent discharge efficiency and its utilization ratio increases greatly at high discharging current density. The results show that the alloy can be used as the negative material in a Ni-MH battery.