| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1279682 | International Journal of Hydrogen Energy | 2007 | 8 Pages |
In this paper, the effects of both Co substitution and annealing treatment on the structures and electrochemical properties of La0.7Mg0.3Ni2.45-xCo0.75+xMn0.1Al0.2La0.7Mg0.3Ni2.45-xCo0.75+xMn0.1Al0.2(x=0.00,0.15,0.30)(x=0.00,0.15,0.30) hydrogen storage alloys have been studied. X-ray diffraction (XRD) analyses show that the main phases of all of the alloys are (La,Mg)Ni3(La,Mg)Ni3 phase (PuNi3PuNi3-type structure) and LaNi5LaNi5 phase (CaCu5CaCu5-type structure). Electrochemical investigations show that increasing Co content and annealing treatment can considerably enhance the cyclic stability of the alloy electrodes. For La0.7Mg0.3Ni2.15Co1.05Mn0.1Al0.2La0.7Mg0.3Ni2.15Co1.05Mn0.1Al0.2 alloy, the value of C100/CmaxC100/Cmax was only 65.5% at its as-cast, however, the value reached 80.5% after an annealing treatment of 1173K×8h. The maximum discharge capacity of the alloy electrodes increased by annealing treatment and decreased slightly when Co content increased from x=0.00x=0.00 to 0.30 at its as-cast state. But the exchange current density (I0)(I0), the limiting current density (IL)(IL) and the diffusion coefficient of hydrogen (D)(D) of the alloy electrodes decreased, leading to a corresponding reduction of the high rate dischargeability (HRD), with increasing Co content and annealing treatment.
