Distribution of hydrogen in metal hydrides studied by in situ powder neutron diffraction
Distribution of hydrogen in metal hydrides studied by in situ powder neutron diffraction
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原位粉末中子衍射研究金属氢化物中氢的分布
DOI：
10.1016/j.nima.2008.11.128
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发表时间：
2009
影响因子：
1.4
通讯作者：
E. Akiba
中科院分区：
文献类型：
--
作者：
Yumiko Nakamura;J. Nakamura;K. Iwase;E. Akiba
用原位粉末中子衍射方法研究了填隙金属颗粒在储氢中的应用。主要焦点是氢原子在材料中的分布。在LaNi 5 −xAlx的完全双晶化过程中，氢的占位与Al的量密切相关，随着占位量的变化，对称性从P63 mc（x=0）变化到P6 mm（x=0.1）和P6/mmm（x = 0.25）。分析了LaNi4.78Sn0.22在吸放氢过程中的氢占有变化。在解吸过程中观察到三个四面体网站之间的再分配。研究了La_5Ni_（19）基La_2Ni_（44）和LaNi_（55）电池叠层结构的复合材料。Rietveld精修结果表明，氢在LaMgNi_（19）D_（24）和LaNi_（55）晶胞（0.8-1.0H/M）中分布均匀，这与这些晶胞的均匀晶格膨胀相一致.这表明Mg取代La改变了La 2Ni 4和LaNi 5电池中氢占据的优先位置。
Interstitial metal hydrides were studied by in situ powder neutron diffraction for their use in hydrogen storage. The main focus was the distribution of hydrogen atoms in the materials. In full hydrides of LaNi5−xAlx, hydrogen occupation depended strongly on the amount of Al. The symmetry varied from P63mc (x=0) to P6mm (x=0.1) and P6/mmm (x⩾0.25) with change in occupancy of each site. Variation in hydrogen occupation during absorption and desorption was analyzed for LaNi4.78Sn0.22. Redistribution between three tetrahedral sites was observed during desorption. La5Ni19-based hydrides with a structure consisting of stacking La2Ni4and LaNi5cells were also studied. Rietveld refinement of La4MgNi19D∼24showed that hydrogen distributed almost evenly in LaMgNi4and LaNi5cells (0.8–1.0H/M), which was consistent with the uniform lattice expansion of those cells. This result indicated that substitution of Mg for La changed the preferred sites for hydrogen occupation in the La2Ni4and LaNi5cells.