Development of a Mg-based hydrogen-storage material by addition of Ni and NbF5 via milling under hydrogen. (21st September 2015)

• Record Type: Journal Article
• Authors: Kwak, Young Jun; Lee, Seong Ho; Mumm, Daniel R.; Song, Myoung Youp
• Is Part Of: International journal of hydrogen energy. Volume 40:Number 35(2015)
• Page Start: 11908
• Page End: 11916
• Publication Date: 2015-09-21
• Subjects: Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.04.111
• Languages: English
• ISSNs: 0360-3199

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">Milling under hydrogen was used to prepare samples with a composition of 80 wt% Mg + 14 wt% Ni + 6 wt% NbF₅ (named 80Mg + 14Ni + 6NbF₅). 80Mg + 14Ni + 6NbF₅ had a large effective storage capacity of hydrogen of approximately 5.6 wt% H. The activation of 80Mg + 14Ni + 6NbF₅ was done after one storing-releasing cycle. At n = 2 at 593 K, 80Mg + 14Ni + 6NbF₅ stored 3.92 and 5.57 wt% H after 2.5 and 60 min, respectively, under 12 bar H₂, and released 2.34 and 4.81 wt% H after 10 and 60 min, respectively, under 1.0 bar H₂. The following reaction happened during milling under hydrogen and at the early storing-releasing cycles: 14Mg + Ni + 4NbF₅ + 7H₂ → MgH₂ + Mg₂NiH₄ + Mg + 10MgF₂ + 4NbH₂. At a fairly low temperature of 423 K, the sample stored 0.28, 0.34, and 0.57 wt% H after 5, 10, and 60 min, respectively. The initial storing rate of 80Mg + 14Ni + 6NbF₅ increased as the temperature rose from the room temperature to 573 K since the effect of thermal activation is predominant, and fell as the temperature rose from 573 K to 623 K since the effect of decrease in the driving force for storing reaction is predominant.</p> </sec> </abstract>