Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7210672 | Rare Metal Materials and Engineering | 2016 | 5 Pages |
Abstract
La1-xSmxMgNi3.6Co0.4 (x = 0â¼0.4) alloys were prepared by a vacuum intermediate frequency induction furnace with a high purity helium gas as the protective atmosphere. The effects of partially substituting Sm for La on the phase structure, morphology and hydrogen storage properties of the alloys were investigated. The detections of XRD and SEM reveal that the as-cast alloys contain two phases, LaMgNi4 and LaNi5. The hydrogen storage capacity (wt%) of the alloys decreases with increasing Sm content, namely 1.859, 1.707, 1.585, 1.578 and 1.471, corresponding the variation of x from 0 to 0.4. The P-C-T curves of the alloys show flat plateaus corresponding to the absorption/desorption pressure plateaus of the LaMgNi4 hydride. Meanwhile, the enthalpy change (ÎH) and entropy change (ÎS) of the LaMgNi4 hydrides for hydriding decrease from â40.37 kJ/mol (x=0) to â26.99 kJ/mol (x=0.4) and from â101.9 J·(mol/K)â1 (x=0) to â77.56 J·(mol/K)â1 (x = 0.4), respectively. The electrochemical measurement displays that the maximum discharge capacity of the alloy electrodes declines from 347 mAh/g to 270.5 mAh/g, which is similar to the trend of the gaseous hydrogen absorption capacity. On the contrary, the cycle stability of the as-cast alloys obviously improves with the Sm content increasing, which can be attributed to the facilitated corrosion resistance by Sm substituting.
Related Topics
Physical Sciences and Engineering
Engineering
Mechanics of Materials
Authors
Zhai Tingting, Yang Tai, Yuan Zeming, Xu Sheng, Zhang Yanghuan,