Crystallographic and Electrochemical Characteristics ofLa_0.7Mg_0.3Ni_4.5–x(Al_0.5Mo_0.5)_x (x = 0–0.8) Hydrogen Storage Alloys

Abstract

Keywords: High-rate dischargeability / Low-temperature dischargeability / Exchange current density / Hydrogen diffusion coefficient / Alloys / X-ray diffractionThe structure, hydrogen storage property, and electrochemical characteristics of the La 0.7 Mg 0.3 Ni 4.5-x (Al 0.5 Mo 0.5 ) x (x = 0, 0.2, 0.4, 0.6, 0.8) hydrogen storage alloys have been investigated systematically. The X-ray powder diffraction and Rietveld analysis results reveal that all the alloys mainly consist of the La(La, Mg) 2 Ni 9 phase and the LaNi 5 phase. The electrochemical measurements show that the maximum discharge capacity increases first from 246.3 (x = 0) to 345.4 mAh/g (x = 0.6) and then decreases to 317.6 mAh/g (x = 0.8), which is consistent with the variation of the hydrogen storage capacity indicated by the P-C isotherms. For the dis-

MgH 2 thin films deposited by one-step reactive plasma sputtering

“…i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 9 ( 2 0 1 4 ) 1 7 7 1 8 e1 7 7 2 5 applications that require heating of the sample. However, room temperature electrochemical charging/discharging might be considered [33].…”

Electrochemical performances of cobalt-free La0.7Mg0.3Ni3.5−x(MnAl2)x (x=0–0.20) hydrogen storage alloy electrodes

“…However, the cyclic stability of these La-Mg-Ni-based hydrogen storage alloy electrodes is unsatisfied. Many studies were carried out to improve the cycling life of the La-Mg-Ni-based hydrogen storage alloy electrodes by partial substitution of Ni with Co [16][17][18][19] and Mo [20,21]. However, Co and Mo are well-known expensive elements in the hydrogen storage alloys.…”

Microstructure and electrochemical hydrogenation/dehydrogenation performance of melt-spun La-doped Mg2Ni alloys

“…Metal hydrides with high weight/volumetric hydrogen storage capacities and reversibly hydrogenating at ambient temperature/pressure successfully applied for or act as electrochemical electrodes can be regarded as significant materials for solving energy and environmental issues [1][2][3]. Mg 2 Ni-type metallic hydrides are looked upon as one of the most promising negative electrodes applied to Ni-MH batteries, which are generally regarded as the preferred power sources for portable power tools, hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), or hydrogen storage materials due to their major superiorities, such as the theoretical electrochemical capacity as high as 1000 mA h/g and gaseous hydrogenation capacity being 3.6 wt.% for Mg 2 NiH 4 [4][5][6]. Magnesium-based (Mg-based) alloys, particularly the Mg 2 Ni-type alloys, appear to be promising electrode materials due to their advantages of lightweight, low-cost and high hydrogen storage capacity, since the traditional AB 5 -type electrodes are restricted by low capacity and relatively high price.…”