The invention discloses a fluorination modification method for AB3-type
hydrogen storage
alloy. Under the protection of
argon gas, raw materials, namely
alloy ingots, of the AB3-type
hydrogen storage
alloy which contains 0.35 stoichiometric proportion of
lanthanum, 0.30 stoichiometric proportion of
praseodymium, 0.35 stoichiometric proportion of
magnesium, 2.90 stoichiometric proportion of
nickel and 0.30 stoichiometric proportion of aluminum are prepared through a
vacuum induction melting method ; after the alloy ingots are ground mechanically, a
ball mill is used for milling the ground alloy ingots for 30-60 minutes at the rotation speed of 225-250
revolutions per minute to obtain milled
hydrogen storage alloy used for
surface modification treatment, and the milled
hydrogen storage alloy is sieved through a
sieve with 200-300 meshes to obtain
hydrogen storage alloy
powder containing the 0.35 stoichiometric proportion of
lanthanum, the 0.30 stoichiometric proportion of
praseodymium, the 0.35 stoichiometric proportion of
magnesium, the 2.90 stoichiometric proportion of
nickel and the 0.30 stoichiometric proportion of aluminum; then the
hydrogen storage alloy
powder is placed into a
beaker containing a solution of
ammonium fluoride (NH4F) with the concentration of 0.1-0.2 mole per
liter and then stirred for 8-12 minutes at the temperature of 40-60 DEG C, and then a solution of
sodium borohydride with the concentration of 0.05-0.06 mole per
liter is added to the mixture dropwise until hydrogen bubbles disappear completely; and after the mixture is subjected to
ultrasound for 0.5-1.5 hours, the hydrogen storage alloy
powder containing the 0.35 stoichiometric proportion of
lanthanum, the 0.30 stoichiometric proportion of
praseodymium, the 0.35 stoichiometric proportion of
magnesium, the 2.90 stoichiometric proportion of
nickel and the 0.30 stoichiometric proportion of aluminum is washed repeatedly with deionized water and then dried for 18-22 hours in a
vacuum state at the temperature of 70-90 DEG C. The circulatory stability performance and the dynamics performance of alloy electrodes, which are modified through the fluorination modification method for the AB3-type hydrogen storage alloy, are both improved.