Superior hydrogen storage and electrochemical properties of Mg_ xNi_(100-x)/Pd films at room temperature

摘要

The Mg_xNi_(100-x) films of 100 nm have been prepared by magnetron co-sputtering Mg and Ni targets, and a Pd layer of 10 nm was deposited on these films by magnetron sputtering a Pd target. Mg_2Ni and MgNi_2 are directly generated during the co-sputtering process in the Mg_(84)Ni_(16)/Pd and Mg_(48)Ni_(52)/Pd films. The hydrogen storage properties of the films under 0.1 MPa H_2 at 298 K were investigated. The hydrogenation of the Mg_(84)Ni_(16)/Pd film saturates within 45 s and exhibits the faster absorption kinetics compared with Mg_(94)Ni_6/Pd and Mg_(48)Ni_(52)/Pd films. The electrochemical properties of the Mg_xNi_(100-x)/Pd films were investigated in 6 M KOH with a three-electrode cell. The Mg_ (84)Ni_(16)/Pd film can be activated just at the first cycle. The maximum discharge capacity of the Mg_(84)Ni_(16)/Pd film is 482.7 mAh g~(-1), the highest among these films.