Effects of V doping on microstructure, kinetic, and thermodynamic characteristics of Zr50‐xVxCo50 (x = 0, 2.5, 3.5, and 5.0) hydrogen storage alloys. (13th January 2022)

• Record Type: Journal Article
• Authors: Liang, Lina; Wang, Feng; Wang, Jiang; Wu, Chengxi; Wang, Zhongmin; Rong, Maohua; Zhou, Huaiying
• Is Part Of: International journal of energy research. Volume 46:Number 5(2022)
• Page Start: 6833
• Page End: 6846
• Publication Date: 2022-01-13
• Subjects: activation behavior -- cycling stability -- hydrogen storage -- V partial substitution -- ZrCo alloy; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.7627
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: To improve the kinetic properties of the ZrCo alloy, Zr50‐ x V x Co50 ( x = 0, 2.5, 3.5, and 5.0) samples were fabricated by vacuum arc‐melting. The effects of the V substitution on the microstructure, hydrogen absorption/desorption kinetics, cycling stability, and antidisproportionation properties of ZrCo were systematically investigated. X‐ray diffraction results show that the Zr50‐ x V x Co50 ( x = 2.5, 3.5, and 5.0) alloys consisted of ZrCo phase and ZrV0.24 Co1.76 second phase. The lattice parameter and cell volume gradually decreased with the increase in the V content. The initial activation behavior was improved for the Zr50‐ x V x Co50 ( x = 2.5, 3.5, and 5.0) samples because of the catalytic effect of the ZrV0.24 Co1.76 second phase. Additionally, the equilibrium pressure of hydrogen absorption increased and the plateau width decreased with the increase in the V content. To obtain thermodynamic and kinetic data, Δ H and E a were calculated using the Van't Hoff equation and Kissinger equation. Δ H of the Zr50‐ x V x Co50 ( x = 0, 2.5, 3.5, and 5.0)‐H system was reduced from 90.12 to 72.52 kJ·mol −1, while E a of ZrCoH3 decreased from 113.38 ± 4.2 to 94.13 ± 2.9 kJ·mol −1 for hydrogen desorption, which is beneficial for the hydrogenation/dehydrogenation reaction. Furthermore, the cycling stability and antidisproportionation properties were enhanced after the V addition, particularly for the Zr47.5 V2.5 Co50 alloy exhibiting an excellent initial activation behavior. Abstract : 1. The brittle second phase ZrV0.24 Co1.76 promotes the generation of cracks in the V‐doped sample, which is conducive to the diffusion of hydrogen atoms to the tetrahedral and octahedral positions. 2. The hydriding kinetic performance is improved for the V‐doped samples due to the catalytic effect of the ZrV0.24 Co1.76 second phase. 3. The hydrogenation/dehydrogenation cycling stability is enhanced for the V‐doped samples.