Pd-capped Mg_(78)Y_(22) thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film,thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to ~1725 mAh·g~(-1).Simultaneously,the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition,the specimen exhibits a very long and flat discharge plateau at about —0.67 V,at which nearly 60%of capacity is maintained.The property is favorable for the application in metal hydride/nickel secondary batteries.The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films. Pd-capped Mg_ (78) Y_ (22) thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been found. It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film, thus facilitating the diffusion of hydrogen atoms and then its discharge capacity to ~ 1725 mAh · g ~ (-1). Simultaneously, the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition, the specimen exhibits a very long and flat discharge plateau at about -0.67 V, at which nearly 60% of capacity is maintained. The property is favorable for the application in metal hydride / nickel secondary batteries. results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.