1. Local structural changes in V–Ti–Cr alloy hydrides with hydrogen absorption/desorption cycling.
- Author
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Ikeda, Kazutaka, Sashida, Sho, Otomo, Toshiya, Ohshita, Hidetoshi, Honda, Takashi, Hawai, Takafumi, Saito, Hiraku, Itoh, Shinichi, Yokoo, Tetsuya, Sakaki, Kouji, Kim, Hyunjeong, Nakamura, Yumiko, Machida, Akihiko, Matsumura, Daiju, and Sławiński, Wojciech A.
- Subjects
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INELASTIC neutron scattering , *HYDRIDES , *HYDROGEN storage , *DESORPTION , *HYDROGEN atom , *VANADIUM - Abstract
Vanadium-based solid solution alloys potentially serve as safe, high-capacity hydrogen storage materials. Low-vanadium-concentration alloys have low durability, and their hydrogen absorption and desorption amounts decrease by 20 % after 100 cycles. In this study, we conducted reverse Monte Carlo modeling on X-ray diffraction patterns and neutron pair distribution functions of the hydrogen-absorbed and desorbed samples of a V 0.10 Ti 0.36 Cr 0.54 alloy to analyze the variations in the local structure. The local structure surrounding the hydrogen atom in the hydrogen-absorbed phase exhibited minimal changes. In contrast, hydrogen occupied both tetrahedral and octahedral sites of the hydrogen-desorbed phase almost equally during the early cycles; however, the amount of hydrogen occupying the tetrahedral sites increased with the number of cycles. It is speculated that hydrogen absorption and desorption cycling induced grain refinement and/or introduced dislocations, which altered both the amount of hydrogen and the sites occupied in the desorbed phase, thereby decreasing the hydrogen storage capacity. [Display omitted] • Degradation mechanism of V–Ti–Cr hydrogen storage alloy revealed by local structure. • Decrease in hydrogen storage consistent with PDF refinements and p – c isotherms. • Cr–H and Ti–H correlations reproduced by a large atomic ensemble in RMC modeling. • Change in hydrogen occupation positions supplemented by inelastic neutron scattering. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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