Precipitation of nanocrystalline LaH3 and Mg2Ni and its effect on de-/hydrogenation thermodynamics of Mg-rich alloys |
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| Affiliation: | 1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi''an, 710072, China;2. School of Materials and Chemical Engineering, Xi''an Technological University, Xi''an, 710072, China;1. School of Materials Science and Engineering and Fujian Provincial Key Laboratory of Functional Materials and Applications, Xiamen University of Technology, Xiamen 361024, China;2. School of Marine Engineering and Fujian Provincial Key Laboratory of Naval Architecture and Ocean Engineering, Jimei University, Xiamen 361021, China;3. Institute of Advanced Wear & Corrosion Resistance and Functional Materials, Jinan University, Guangzhou 510632, China;1. School of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, China;2. Inner Mongolia Key Laboratory of New Metal Materials, Baotou 014010, China;1. Center for Energy Materials Research, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea;2. Department of Materials Science and Engineering, Korea University, Seoul, 02841, Republic of Korea;3. Advanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of Korea;4. Advanced Materials Engineering, University of Science and Technology, Daejeon, 34113, Republic of Korea;1. National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, PR China;2. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, PR China;1. Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou, 014010, China;2. Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing, 100081, China;3. Weishan Cisri-Rare Earth Materials Co., Ltd., Jining, 277600, China;1. National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, PR China;2. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, PR China |
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| Abstract: | Based on the catalytic effects of transition metals and rare earth metals on magnesium hydride, precipitation behavior of nanocrystalline LaH3 and Mg2Ni has been discussed and correlated with the de-/hydrogenation thermodynamic of Mg-rich alloys in this work. The results show that a significant enhancement of de-/hydrogenation properties has been achieved due to in-situ formed Mg–Mg2Ni–LaH3 nanocomposites. It is observed that the Mg2Ni-rich alloy exhibiting superior performance can desorb about 5.7 wt% hydrogen within 2.5 min at 623 K. The formation of LaH3 tends to promote the hydrogenation process and the Mg2Ni is beneficial for improving the dehydrogenation performance. Meanwhile, the phase boundaries between LaH3, Mg2Ni and Mg also play positive roles due to stored extra energy on the interface. Fitting kinetics model shows that rate-limiting steps of the as-prepared alloys have changed and the desorption activation energy significantly decreases due to precipitation of nanocrystalline LaH3 and Mg2Ni. It is worth noting that desorption activation energy of the preferable composite decreases to 94.03 kJ mol?1. Thermodynamic properties are also investigated and analyzed based on plateau pressure and van't Hoff equation. It is revealed that precipitation of nanocrystalline LaH3 and Mg2Ni significantly enhances the hydrogen storage kinetics of Mg-based alloys. |
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| Keywords: | Hydrogen storage De-/hydrogenation thermodynamics Rate-limiting steps |
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