Electrochemical hydrogen storage performances of Mg–Ti–Ni–Co–Al-based alloys prepared by mechanical milling

Abstract The higher thermodynamic stability and hysteretic kinetics hinder the development of magnesium-based materials to the vehicles. In this paper, for the sake of enhancing the properties of Mg–Ni-based materials, Ti partial substitution of Mg and the mechanical milling technologies with different milling durations were utilized to synthesize Mg–Ni-based Mg50-xTixNi45Al3Co2 (x = 0, 1) + 50 wt%Ni (Mg50-xTixNi45Al3Co2 (x = 0, 1) + 50Ni) composites that have the structures of nanocrystalline and amorphism. The electrochemical tests show that the as-milled alloys have the ability to freely realize electrochemical hydrogen absorption and desorption at normal temperature. Besides, the performances cycle steadiness and discharge capacity of the sample both conspicuously grow by extending the milling duration. In particular, the discharge capacity increases in the range of 343.6–468.8 mAh/g and the specimen's (x = 1) capacity retention rate after 100 cycles (S100 = C100/Cmax) augments from 41% to 57% with the milling time changing from 5 h to 20 h. What's more, some kinetics and electrochemical tests (HRD, EIS, etc.) show that the electrochemical kinetics characteristics can get a significant improvement with the prolongation of milling time.