Crystal structure and hydrogen absorption–desorption properties of Ca3Mg2Ni13
Crystal structure and hydrogen absorption–desorption properties of Ca3Mg2Ni13
复制标题
DOI：
10.1016/j.actamat.2008.12.040
复制
发表时间：
2009-04
期刊：
影响因子：
9.4
通讯作者：
Q. Zhang;Gang Pang;T. Si;D. Liu
中科院分区：
文献类型：
--
作者：
Q. Zhang;Gang Pang;T. Si;D. Liu
在Ca-Mg-Ni体系中发现了新的化合物Ca{sub 3}Mg{sub 2}Ni{sub 13}，并用x射线衍射和高分辨率透射电镜对其晶体结构进行了研究。Ca{sub 3}Mg{sub 2}Ni{sub 13}在空间群R3-barm （No. 166）中结晶；电池参数：a = 4.9783(2) a, c = 36.180(2) a；Z = 3。Ca{sub 3}Mg{sub 2}Ni{sub 13}结构在一个周期内有三个块沿c轴堆叠，每个块由两个子块组成。其中一个只包含一层[CaMgNi{sub 4}]单元，另一个包含一层[CaMgNi{sub 4}]单元和一层[CaNi{sub 5}]单元。进一步研究表明，Ca{sub 3}Mg{sub 2}Ni{sub 13}对氢的吸附和解吸具有良好的动力学性质，但热力学性质较差。而Ca{sub 3}Mg{sub 2}Ni{sub 13}型化合物的Ca/Mg比值可以在较宽的范围内调节，以提高其吸氢-解吸性能。结果表明，Ca{sub 1.67}Mg{sub 3.33}Ni{sub 13}具有良好的热力学性质和良好的吸氢-解吸可逆性。
The novel compound Ca{sub 3}Mg{sub 2}Ni{sub 13} has been found in the Ca-Mg-Ni system, and its crystal structure has been investigated by X-ray diffraction and high-resolution transmission electron microscopy. Ca{sub 3}Mg{sub 2}Ni{sub 13} crystallizes in space group R3-barm (No. 166); cell parameters: a = 4.9783(2) A and c = 36.180(2) A; Z = 3. The Ca{sub 3}Mg{sub 2}Ni{sub 13} structure has three blocks stacked along the c axis in one period, and each block is composed of two sub-blocks. One only contains one layer of [CaMgNi{sub 4}] units, and the other consists of one layer of [CaMgNi{sub 4}] units and one layer of [CaNi{sub 5}] units. Further investigations show that Ca{sub 3}Mg{sub 2}Ni{sub 13} has good kinetic properties but bad thermodynamic properties for hydrogen absorption-desorption. However, the Ca/Mg ratio of the Ca{sub 3}Mg{sub 2}Ni{sub 13}-type compound can be adjusted within a wide range to improve the hydrogen absorption-desorption properties. As a result, Ca{sub 1.67}Mg{sub 3.33}Ni{sub 13} shows favorable thermodynamics and has good reversibility for hydrogen absorption-desorption.