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Effects of Ti and Co 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.200790237
Subject(s) - alloy , tafel equation , materials science , electrochemistry , scanning electron microscope , hydrogen storage , metallurgy , electrode , polarization (electrochemistry) , corrosion , chemical engineering , chemistry , composite material , engineering
Mg‐based hydrogen storage alloys MgNi, Mg 0.9 Ti 0.1 Ni and Mg 0.9 Ti 0.1 Ni 0.9 Co 0.1 were successfully prepared by means of mechanical alloying (MA). The structure and the electrochemical characteristics of these Mg‐based materials were also studied. The results of X‐ray diffraction (XRD) and scanning electron microscopy (SEM) show that the main phases of the alloys exhibit amorphous structures, and trace of Ni co‐exists. The charge‐discharge cycle tests indicate these alloys have good electrochemical active characteristics. And the cycle stability of Ti and Co doped alloy was better than that of MgNi alloy. After 50 cycle charge‐discharge, the discharge capacity of the Mg 0.9 Ti 0.1 Ni 0.9 Co 0.1 alloy was much better than that of MgNi and Mg 0.9 Ti 0.1 Ni alloys. The discharge capacity of Mg 0.9 Ti 0.1 Ni 0.9 Co 0.1 was 102.8% higher than that of MgNi alloy, and 45.49% higher than that of the Mg 0.9 Ti 0.1 Ni alloy. During the process of charge‐discharge cycle test, the main reason for the electrode capacity fading is the corrosion of Mg to Mg(OH) 2 on the surface of alloys. The Tafel polarization test indicates Ti and Co improve the anticorrosion in an alkaline solution. The EIS results suggest that proper amount of Ti and Co doping improve the electrochemical catalytical activity on the Mg‐based alloy surface significantly.