Superior electrochemical characteristics of A₂B₇-type hydrogen storage alloy at ultralow temperature with the addition of alane

In an attempt to enhance the low-temperature dischargeability of A₂B₇-type hydrogen storage alloy, the addition of alane (AlH₃) by convenient ball milling method was investigated based on La-Y-Ni superlattice alloy containing Y₂Ni₇-type phase and YNi₃-type phase primarily. The maximum discharge capacity of the composite with doping 1 wt.% AlH₃ increased by 364.2% reaching 208.9 mAh g⁻¹ at 233 K compared with the pristine sample. The initial high-rate discharge capacity of doping 1 wt.% AlH₃ sample reached 151.7 mAh g⁻¹ at 4000 mA g⁻¹ current density. The improvement could be ascribed to strengthening of hydrogen diffusion channel and acceleration of H-kinetics at low temperatures derived from formation of new porous structure and modification of lattice defects by dissolution of aluminum on the surface. It has made a powerfully contribution to a pace of commercialization of A₂B₇-type superlattice hydrogen storage alloy applying in high altitude or latitude regions.