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Effects of Ti and Zr Substituted on the Electrochemical Characteristics of MgNi‐Based Alloy Electrodes
Author(s) -
Feng Yan,
Jiao LiFang,
Yuan HuaTang,
Zhao Ming
Publication year - 2007
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200790035
Subject(s) - alloy , scanning electron microscope , electrochemistry , dielectric spectroscopy , materials science , amorphous solid , electrode , hydrogen storage , metallurgy , polarization (electrochemistry) , corrosion , diffraction , doping , chemical engineering , chemistry , composite material , crystallography , engineering , physics , optoelectronics , optics
Mg‐based hydrogen storage alloys MgNi, Mg 0.9 Ti 0.1 Ni, and Mg 0.9 Ti 0.06 Zr 0.04 Ni were successfully prepared by means of mechanical alloying (MA). The structure and the electrochemical characteristics of these Mg‐based materials were studied. The X‐ray diffraction (XRD) result shows that the main phases of the alloys exhibit amorphous structure. The scanning electron microscopy (SEM) photograph shows that the particle size of Ti and Zr substituted alloys was about 2–4 µm in diameter. The cycle lives of the alloys were prolonged by adding Ti and Zr. After 50 charge‐discharge cycles, the discharge capacity of Mg 0.9 Ti 0.06 Zr 0.04 Ni was 91.74% higher than that of MgNi alloy and 37.96% higher than that of Mg 0.9 Ti 0.1 Ni alloy. The main reason for the electrode capacity decay is the formation of Mg(OH) 2 (product of Mg corrosion) at the surface of alloy. The potentiodynamic polarization result indicates that Ti and Zr doping improves the anticorrosion in an alkaline solution. The electrochemical impedance spectroscopy (EIS) results suggest that proper amount of Ti and Zr doping improves the electrochemical catalytic activity significantly.