Amorphous hydrogen storage alloys Mg0.9Ti0.1Ni1-xPdx (x = 0-0.15) were prepared by mechanical alloying (MA). The electrochemical performances of electrode alloys were studied by cyclic charge-discharge experiment, linear polarization and electrochemical impedance spectroscopy. The capacity retention rate C-20th/C-max of quaternary Mg0.9Ti0.1Ni1-xPdx (x = 0.05, 0.1, 0.15) alloys are 66.2%, 75% and 76.8%, respectively, much higher than that of Mg0.9Ti0.1Ni (31.4%). It was demonstrated that the substitution of Pd for Ni improved the cyclic stability of MgTiNi-based electrode alloy greatly. The partial substitution of Pd for Ni also led to the increase of exchange current density I-0, which concluded that the reaction activity on the surface of alloys was effectively improved. (c) 2006 Elsevier B.V. All rights reserved.