The effects of Ni/Co ratios on A2B7-type La0.7Mg0.3 (Ni1-xCox)3.5 （0≤x≤0.5） alloys were investigated. The results showed that the discharge capacity of the alloys first increased from 245 to 392 mAh·g-1, then decreased to 316 mAh·g-1, corresponding to x=0, 0.2 and 0.5, respectively. While the electrochemical impedance spectra indicated that the reaction resistance had the opposite tendency. When x is equal to 0.2, the reaction resistance has the lowest value. The electrochemical P-C-T results are consistent with the discharge ones of the alloys. When x is equal to 0.2, the dehydriding capacity is 1.34wt.%.
