放电等离子烧结技术制备La0.7Mg0.3Ni2.5Co(下标 x)贮氢合金性能研究

The La0.7Mg0.3Ni2.5Co(subscript x) (x=0.1, 0.2, 0.3, 0.4, 0.5) hydrogen storage alloys were prepared by spark plasma sintering (SPS). The phase structure, hydrogen storage performance and electrochemical performance of the alloys were studied by XRD, three-electrode test system and electrochemical impedance spectra. The results show that the alloys are mainly composed of (La, Mg) 2Ni7 and (La, Mg) Ni3. The hydrogen storage capacity of the alloys increased then decrease with the increasing of x and it is 1.37% when x=0.4. The maximum discharge capacity of the alloys is 365.4 mAh/g. The activation performance of the alloys is excellent (the number of activation is only 1 time). The desorption plateau pressure of hydrogen storage alloys and the charge transfer rate of the electrode surface increases with the increasing of x.