Changes in crystal structure and hydrogenation characteristics by Li substitution for the Ni site of Laves phase(Ca0.32Mg0.68)Ni2 hydrogen storage alloy
The structural and hydrogenation properties of Laves phase hydrogen storage alloys(Ca0.32Mg0.68)(Ni1-xLix) for x = 0, 0.3, 0.5 were investigated. It has been cleared using the Rietveld analysis that mass ratio of the C15-type cubic Laves phase compound decreased in exchange for the ratio of the C36-type hexagonal one increased with increasing the Li content, where the lattice constants of both the C15 and C36 phase compounds decreased. Small amounts of impurities of CaMg2 and CaLi2 were found in the sample except for x=0. On the other hand, with increasing the Li content, the amount of hydrogen storage of the sample decreased and the hydrogen equilibrium pressure measured in the PCT curve increased. Van’t Hoff plot of the sample for x=0.3 showed that both values of the standard enthalpy ΔH0 and the standard entropy ΔS0 were negative and the absolute value of them became smaller than those of the sample for x=0. These results mentioned above indicate that the hydrides of this system become unstable by substituting Li for Ni, because of the structural change from the C15 to the C36 phase and the reduction of the lattice constant.
雑誌名
三重大学教育学部研究紀要 自然科学・人文科学・社会科学・教育科学・教育実践
雑誌名(英)
Bulletin of the Faculty of Education, Mie University. Natural Science, Humanities, Social Science, Education, Educational Practice
ラーベス相(Ca0.32Mg0.68)Ni2水素吸蔵合金のLi 置換による結晶構造と水素化特性の変化
2019BS0070.pdf
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