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Journal of Chemistry
Volume 2013, Article ID 627582, 6 pages
http://dx.doi.org/10.1155/2013/627582
Research Article

Investigation on the Structure and Electrochemical Properties of La-Ce-Mg-Al-Ni Hydrogen Storage Alloy

1State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, CAS, Changchun 130022, China
2College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, China
3Department of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China

Received 28 October 2013; Accepted 23 November 2013

Academic Editor: Xinqing Chen

Copyright © 2013 Yuqing Qiao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Structure and electrochemical characteristics of La0.96Ce0.04Mg0.15Al0.05Ni2.8 hydrogen storage alloy have been investigated. X-ray diffraction analyses reveal that the La0.96Ce0.04Mg0.15Al0.05Ni2.8 hydrogen storage alloy consisted of a (La, Mg)Ni3 phase with the rhombohedral PuNi3-type structure and a LaNi5 phase with the hexagonal CaCu5-type structure. TEM shows that the alloy is multicrystal with a lattice space 0.187 nm. EDS analyse shows that the content of Mg is 3.48% (atom) which coincide well with the designed composition of the electrode alloy. Electrochemical investigations show that the maximum discharge capacity of the alloy electrode is 325 mAh g−1. The alloy electrode has higher discharge capacity within the discharge current density span from 60 mA g−1 to 300 mA g−1. Electrochemical impedance spectroscopy measurements indicate that the charge transfer resistance on the alloy electrode surface and the calculated exchange current density I0 are 0.135 Ω and 1298 mA g−1, respectively; the better eletrochemical reaction kinetic of the alloy electrode may be responsible for the better high-rate dischargeability.