Investigation of the structure, phase composition, and electrochemical characteristics of hydrogen-sorbing intermetallics of the La–Мg–Ni system obtained by the sintering method

Authors

DOI:

https://doi.org/10.17721/fujcV6I1P1-6

Keywords:

sintering, phase composition, discharge capacity, kinetics, cyclic stability

Abstract

The crystal structure, phase composition, and electrochemical properties of the materials obtained by sintering of (LaNi3+Mg+Ni) powder mixture in the temperature range 640–1020°С have been investigated. Experimental results show that, at temperatures of ≤850°С, the sintered multiphase material, whose major phases are phases with PuNi3-type structure (LaMg2Ni9 and LaNi3) and CaCu5-type structure (LaNi5), is formed. With increase in temperature, the number of phases in the sintered material decreases to a single major phase LaNi5, and the content of the LaMg2Ni9 phase practically does not change. It has been established that increase in sintering temperature deteriorates the activation of the electrode materials and slows down the hydrogen absorption process. At the same time, the maximum discharge capacity and cyclic stability of electrodes increase.

Author Biography

Artem Krynytskyi, Institute for problems of materials science NASU

Engineer

References

Li Y, Han S, Li J, Zhu X, Hu L. Study on kinetics and electrochemical properties of Ml0.70Mg0.30(Ni3.95Co0.75Mn0.15Al0.15)x (x=0.60, 0.64, 0.68, 0.70, 0.76) alloys. Materials Chemistry and Physics 2008;108(1):92-96. https://doi.org/10.1016/j.matchemphys.2007.09.009

Liao B, Lei Y, Chen L, Lu G, Pan H, Wang Q. Effect of the La/Mg ratio on the structure and electrochemical properties of LaxMg3−xNi9 (x=1.6–2.2) hydrogen storage electrode alloys for nickel–metal hydride batteries. Journal of Power Sources 2004;129(2):358-367. https://doi.org/10.1016/j.jpowsour.2003.11.044

Dong Z, Wu Y, Ma L, Wang L, Shen X, Wang L. Electrochemical hydrogen storage properties of non-stoichiometric La0.7Mg0.3−xCaxNi2.8Co0.5 (x=0–0.10) electrode alloys. Journal of Alloys and Compounds 2011;509(17):5280-5284. https://doi.org/10.1016/j.jallcom.2010.11.132

Nwakwuo C, Holm T, Denys R, Hu W, Maehlen J, Solberg J, Yartys V. Effect of magnesium content and quenching rate on the phase structure and composition of rapidly solidified La2MgNi9 metal hydride battery electrode alloy. Journal of Alloys and Compounds 2013;555:201-208. https://doi.org/10.1016/j.jallcom.2012.12.017

Kadir K, Sakai T, Uehara I. Structural investigation and hydrogen storage capacity of LaMg2Ni9 and (La0.65Ca0.35)(Mg1.32Ca0.68)Ni9 of the AB2C9 type structure. Journal of Alloys and Compounds 2000;302(1-2):112-117. https://doi.org/10.1016/s0925-8388(00)00581-8

Liao B, Lei Y, Lu G, Chen L, Pan H, Wang Q. The electrochemical properties of LaxMg3−xNi9 (x=1.0–2.0) hydrogen storage alloys. Journal of Alloys and Compounds 2003;356-357:746-749. https://doi.org/10.1016/s0925-8388(03)00083-5

Liao B, Lei Y, Chen L, Lu G, Pan H, Wang Q. A study on the structure and electrochemical properties of La2Mg(Ni0.95M0.05)9 (M = Co, Mn, Fe, Al, Cu, Sn) hydrogen storage electrode alloys. Journal of Alloys and Compounds 2004;376(1-2):186-195. https://doi.org/10.1016/j.jallcom.2003.12.011

Downloads

Published

2018-07-24