Phase structure and hydrogen storage properties of LaMg_(3.70)Ni_(1.18) alloy
The phase structure and hydrogen storage properties of LaMg 3.70 Ni 1.18 alloy were investigated. The LaMg 3.70 Ni 1.18 alloy consists of main LaMg 2 Ni phase, minor La 2 Mg 17 and LaMg 3 phases. The alloy can be activated in the first hydriding/dehydriding process, and initial LaMg 2 Ni, La 2 Mg 17...
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Published in | 稀有金属:英文版 Vol. 30; no. 5; pp. 458 - 463 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
2011
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Subjects | |
Online Access | Get full text |
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Summary: | The phase structure and hydrogen storage properties of LaMg 3.70 Ni 1.18 alloy were investigated. The LaMg 3.70 Ni 1.18 alloy consists of main LaMg 2 Ni phase, minor La 2 Mg 17 and LaMg 3 phases. The alloy can be activated in the first hydriding/dehydriding process, and initial LaMg 2 Ni, La 2 Mg 17 , and LaMg 3 phases transfer to LaH 2.34 , Mg, and Mg 2 Ni phases after activation. The reversible hydrogen storage capacity of the LaMg 3.70 Ni 1.18 alloy is 2.47 wt.% at 558 K, which is higher than that of the LaMg 2 Ni alloy. The pressure-composition-temperature (PCT) curves display two hydriding plateaus, corresponding to the formation of MgH 2 and Mg 2 NiH 4 . However, only one dehydriding plateau is observed, owing to the synergetic effect of hydrogen desorption between MgH 2 and Mg 2 NiH 4 . The uptake time for hydrogen content to reach 99% of saturated state is less than 250 s, and 90% hydrogen can be released in 1200 s in the experimental conditions, showing fast kinetics in hydriding and dehydriding. The activation energies of the LaMg 3.70 Ni 1.18 alloy are –51.5 ± 1.1 kJ/mol and –57.0 ± 0.6 kJ/mol for hydriding and dehydriding, respectively. The hydriding/dehydriding kinetics of the LaMg 3.70 Ni 1.18 alloy is better than that of the Mg 2 Ni alloy, owing to the lower activation energy values. |
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Bibliography: | LI Jinhua a , LIU Baozhong a, b , HAN Shumin a, c , HU Lin c , ZHAO Xin c , and WANG Mingzhi a a State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China b School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China c College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China hydrogen storage alloys; multiphase structure; hydrogen storage properties; rare earths The phase structure and hydrogen storage properties of LaMg 3.70 Ni 1.18 alloy were investigated. The LaMg 3.70 Ni 1.18 alloy consists of main LaMg 2 Ni phase, minor La 2 Mg 17 and LaMg 3 phases. The alloy can be activated in the first hydriding/dehydriding process, and initial LaMg 2 Ni, La 2 Mg 17 , and LaMg 3 phases transfer to LaH 2.34 , Mg, and Mg 2 Ni phases after activation. The reversible hydrogen storage capacity of the LaMg 3.70 Ni 1.18 alloy is 2.47 wt.% at 558 K, which is higher than that of the LaMg 2 Ni alloy. The pressure-composition-temperature (PCT) curves display two hydriding plateaus, corresponding to the formation of MgH 2 and Mg 2 NiH 4 . However, only one dehydriding plateau is observed, owing to the synergetic effect of hydrogen desorption between MgH 2 and Mg 2 NiH 4 . The uptake time for hydrogen content to reach 99% of saturated state is less than 250 s, and 90% hydrogen can be released in 1200 s in the experimental conditions, showing fast kinetics in hydriding and dehydriding. The activation energies of the LaMg 3.70 Ni 1.18 alloy are –51.5 ± 1.1 kJ/mol and –57.0 ± 0.6 kJ/mol for hydriding and dehydriding, respectively. The hydriding/dehydriding kinetics of the LaMg 3.70 Ni 1.18 alloy is better than that of the Mg 2 Ni alloy, owing to the lower activation energy values. 11-2112/TF |
ISSN: | 1001-0521 1867-7185 |