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Title: Structural transitions of ternary imide Li{sub 2}Mg(NH){sub 2} for hydrogen storage

Phase transitions and energetic properties of Li{sub 2}Mg(NH){sub 2} with different crystal structures are investigated by experiments and first-principles calculations. The Li{sub 2}Mg(NH){sub 2} with the primitive cubic and orthorhombic structure is obtained by dynamically dehydrogenating a Mg(NH{sub 2}){sub 2}-2LiH mixture up to 280 °C under an initial vacuum and 9.0 bars H{sub 2}, respectively. It is found that the obtained orthorhombic Li{sub 2}Mg(NH){sub 2} is converted to a primitive cubic structure as the dehydrogenation temperature is further increased to 400 °C or performed by a 36 h of high-energetic ball milling. Moreover, the primitive cubic phase can be converted to an orthorhombic phase after heating at 280 °C under 9.0 bars H{sub 2} for 1 h. Thermodynamic calculations show that the orthorhombic phase is the ground state structure of Li{sub 2}Mg(NH){sub 2}. The mechanism for phase transitions of Li{sub 2}Mg(NH){sub 2} is also discussed from the angle of energy.
Authors:
 [1] ;  [2] ; ; ;  [3]
  1. College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China)
  2. (China)
  3. State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)
Publication Date:
OSTI Identifier:
22310998
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPUTERIZED SIMULATION; DEHYDROGENATION; GROUND STATES; HYDROGEN; HYDROGEN COMPOUNDS; HYDROGEN STORAGE; LITHIUM COMPOUNDS; MAGNESIUM COMPOUNDS; MIXTURES; NITROGEN COMPOUNDS; ORTHORHOMBIC LATTICES; PHASE TRANSFORMATIONS