Electrochemical properties of Mg-based alloys containing carbon nanotubes

In this work, effects of partial substitution of Mg, Ni with AB₂ in Mg-based alloy and subsequent surface modification by further ball-milling with carbon nanotubes (CNTs) on electrochemical properties were investigated. Mg_1.9(AB₂)_0.1Ni_0.8 (AB₂=LaNi₂, LaNiCo and LaNiMn) alloys were prepared by solid-state diffusion method, the nanocrystalline Mg-based alloys were prepared by ball-milling the mixture of obtained Mg_1.9(AB₂)_0.1Ni_0.8 alloys and nickel powder. It was found that the electrochemical capacities of nanocrystalline Mg_1.9(AB₂)_0.1Ni_1.8 alloys were measured to be 460–490 mAh/g. The nanocrystalline Mg-based alloys containing carbon nanotubes (10 wt.%) obtained by ball-milling after 60 min were demonstrated to show improved electrochemical properties with respect to the original nanocrystalline Mg-based alloys. The electrochemical reaction activity was detected by electrochemical impedance spectra (EIS). Raman and X-ray photoelectron spectroscopy (XPS) proved the interaction between Mg_1.9(AB₂)_0.1Ni_1.8 alloys and carbon nanotubes after ball-milling, which resulted in an increase in the surface Ni/Mg ratio.