Yuan Li, Yang Tao, and Quan Huo, Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys, Int. J. Miner. Metall. Mater., 22(2015), No. 1, pp.86-93. https://dx.doi.org/10.1007/s12613-015-1047-5
Cite this article as:
Yuan Li, Yang Tao, and Quan Huo, Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys, Int. J. Miner. Metall. Mater., 22(2015), No. 1, pp.86-93. https://dx.doi.org/10.1007/s12613-015-1047-5
Yuan Li, Yang Tao, and Quan Huo, Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys, Int. J. Miner. Metall. Mater., 22(2015), No. 1, pp.86-93. https://dx.doi.org/10.1007/s12613-015-1047-5
Cite this article as:
Yuan Li, Yang Tao, and Quan Huo, Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys, Int. J. Miner. Metall. Mater., 22(2015), No. 1, pp.86-93. https://dx.doi.org/10.1007/s12613-015-1047-5
Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
Funds:
the National Natural Science Foundation of China(Nos.21303157 and 21106123), the Natural Science Foundation of Hebei Province,China(No.B2012203104), the China Postdoctoral Science Foundation Project(2013M541201), and the Research Fund for the Doctoral Program of Higher Education of China(20131333120008).
Received:
29 April 2014;
Revised:
12 June 2014;
Accepted:
15 June 2014;
Available Online:
09 June 2021
To improve the electrochemical properties of rare-earth-Mg-Ni-based hydrogen storage alloys, the effects of stoichiometry and Cu-substitution on the phase structure and thermodynamic properties of the alloys were studied. Nonsubstituted Ml0.80Mg0.20(Ni2.90Co0.50-Mn0.30Al0.30)x (x=0.68, 0.70, 0.72, 0.74, 0.76) alloys and Cu-substituted Ml0.80Mg0.20(Ni2.90Co0.50-y Cuy Mn0.30Al0.30)0.70 (y=0, 0.10, 0.30, 0.50) alloys were prepared by induction melting. Phase structure analysis shows that the nonsubstituted alloys consist of a LaNi5 phase, a LaNi3 phase, and a minor La2Ni7 phase; in addition, in the case of Cu-substitution, the Nd2Ni7 phase appears and the LaNi3 phase vanishes. Thermodynamic tests show that the enthalpy change in the dehydriding process decreases, indicating that hydride stability decreases with increasing stoichiometry and increasing Cu content. The maximum discharge capacity, kinetic properties, and cycling stability of the alloy electrodes all increase and then decrease with increasing stoichiometry or increasing Cu content. Furthermore, Cu substitution for Co ameliorates the discharge capacity, kinetics, and cycling stability of the alloy electrodes.
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