Abstract In order to find out the effect of lattice configuration on the structural stability of Rare earth magnesium nickel compounds, two La0.65Nd0.15Mg0.20Ni3.50 isomerides with single Ce2Ni7-type (2H) and single Gd2Co7-type (3R) structure, respectively, have been prepared for the first time. It is found that, after hydrogenation/dehydrogenization cycles, the volume of [A2B4] subunit in 3R-type structure shrinks while that of [A2B4] in 2H-type structure gets expanded. Meanwhile, the [AB5] subunits in both structures expand, which have smaller initial volumes than [A2B4] subunits. The standard deviation of subunit volumes σ(V[A2B4], V[AB5]) in 3R-type structure is always smaller than that of 2H-type structure, and the σ(V[A2B4], V[AB5]) in 3R-type structure is only 0.45 A3, far less than that of 2H-type compound (2.11 A3) after 50 cycles. The lattice microstrain in 3R-type structure is quite lower than that in 2H-type structure and the 3R-type structure possesses a superior structural stability and higher anti-pulverization ability. After 50 cycles, the capacity retention of 3R-type compounds is 100% while that of 2H-type compounds is only 87.44%. Transmission electron microscope and X-ray diffraction analyses show that the crystal structure of 3R-type compound is almost unchanged after 50 cycles, while, severe lattice deformation is observed in 2H-type structure.

中文翻译：

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具有 La0.6Nd0.15Mg0.25Ni3.5 成分的单相 Ce2Ni7 型和 Gd2Co7 型异构体的结构稳定性研究

摘要 为了探究晶格构型对稀土镁镍化合物结构稳定性的影响，研究了两种具有单一 Ce2Ni7 型 (2H) 和单一 Gd2Co7 型 (3R) 结构的 La0.65Nd0.15Mg0.20Ni3.50 异构体。 ，分别是第一次准备。研究发现，经过加氢/脱氢循环后，3R型结构中[A2B4]亚基的体积缩小，而2H型结构中[A2B4]亚基的体积膨胀。同时，两种结构中的 [AB5] 亚基都膨胀，其初始体积小于 [A2B4] 亚基。3R型结构中亚基体积σ(V[A2B4], V[AB5])的标准差总是小于2H型结构，3R中的σ(V[A2B4],V[AB5])型结构仅为0.45 A3，远低于50次循环后的2H型化合物（2.11 A3）。3R型结构的晶格微应变远低于2H型结构，3R型结构具有优越的结构稳定性和更高的抗粉化能力。50次循环后，3R型化合物的容量保持率为100%，而2H型化合物的容量保持率仅为87.44%。透射电子显微镜和 X 射线衍射分析表明，3R 型化合物的晶体结构在 50 次循环后几乎没有变化，而在 2H 型结构中观察到严重的晶格变形。