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Title: Hydriding and dehydriding characteristics of LiBH{sub 4} and transition metals-added magnesium hydride

Graphical abstract: Hydriding reaction curves under 12 bar H{sub 2}, and dehydriding reaction curves under 1.0 bar H{sub 2}, at 593 K at the 1st cycle for MgH{sub 2}–10Ni–2LiBH{sub 4}–2Ti and MgH{sub 2}. Highlights: ► Addition of Ni, LiBH{sub 4}, and Ti to MgH{sub 2} to increase reaction rates. ► Sample preparation by reactive mechanical grinding. ► At n = 2, the sample absorbed 4.05 wt% H for 60 min at 593 K under 12 bar H{sub 2}. ► Analysis of rate-controlling step for dehydriding of the sample at n = 3. - Abstract: In this study, MgH{sub 2} was used as a starting material instead of Mg. Ni, Ti, and LiBH{sub 4} with a high hydrogen-storage capacity of 18.4 wt% were added. A sample with a composition of MgH{sub 2}–10Ni–2LiBH{sub 4}–2Ti was prepared by reactive mechanical grinding. The activation of MgH{sub 2}–10Ni–2LiBH{sub 4}–2Ti was completed after the first hydriding–dehydrding cycle. The hydriding rate decreases as the temperature increases due to the decrease in the driving force for the hydriding reaction. At the 1st cycle, the sample desorbs 1.45 wt% H for 10 min, 2.54 wt% H for 20 min, 3.13 wt% H for 30 min, and 3.40 wt% Hmore » for 60 min at 593 K under 1.0 bar H{sub 2}. At the 2nd cycle, the sample absorbs 3.84 wt% H for 5 min, 3.96 wt% H for 10 min, and 4.05 wt% H for 60 min at 593 K under 12 bar H{sub 2}. MgH{sub 2}–10Ni–2LiBH{sub 4}–2Ti after reactive mechanical grinding contained MgH{sub 2}, Mg, Ni, TiH{sub 1.924}, and MgO phases. The reactive mechanical grinding of Mg with Ni, LiBH{sub 4}, and Ti is considered to create defects on the surface and in the interior of Mg (to facilitate nucleation), and to reduce the particle size of Mg (to shorten diffusion distances of hydrogen atoms). The formation of Mg{sub 2}Ni during hydriding–dehydriding cycling increases the hydriding and dehydriding rates of the sample.« less
Authors:
 [1] ; ;  [2] ;  [3]
  1. Division of Advanced Materials Engineering, Hydrogen and Fuel Cell Research Center, Engineering Research Institute, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, 561-756 (Korea, Republic of)
  2. Department of Materials Engineering, Graduate School, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, 561-756 (Korea, Republic of)
  3. Faculty of Applied Chemical Engineering, Chonnam National University, 300 Yongbongdong, Bukgu, Gwangju, 500-757 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22290457
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 7; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ELECTRON MICROSCOPY; ENERGY STORAGE; GRINDING; HYDRIDATION; HYDROGEN; HYDROGEN STORAGE; MAGNESIUM HYDRIDES; MAGNESIUM OXIDES; PARTICLE SIZE; TRANSITION ELEMENTS; X-RAY DIFFRACTION