Understanding crystal structure roles towards developing high-performance V-free BCC hydrogen storage alloys. (15th July 2022)

• Record Type: Journal Article
• Authors: Hu, Huazhou; Ma, Chuanming; Zhou, Lu; Xiao, Houqun; Chen, Qingjun
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 60(2022)
• Page Start: 25335
• Page End: 25346
• Publication Date: 2022-07-15
• Subjects: Hydrogen storage alloys -- V-free -- Hydrogen storage mechanisms -- Microstructures -- Rapid cooling; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.05.241
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Current bottlenecks in the supply and high cost of V have negatively impacted their application. There is great interest in developing V-based hydrogen storage alloys that use less or free V. Here, we investigate the role of V in deliberately designed V-based alloys. Our results affirm that V plays an undeniable role in enhancing hydrogen storage properties. It is found that V maintains the stable single BCC structure but leads to more residual hydrogen (1.4 wt%) because of the high stability of the dihydride and smaller hydriding rate because of the small lattice parameter, which offers unexpected but encouraging perspectives towards reducing the need of V in such alloys. Mo substitution for V effectively alleviates the higher residual hydrogen to achieve a high dehydriding capacity of 2.5 wt%. Moreover, the suction-cast (Ti0.46 Cr0.54 )97.5 Mo2.5 alloy, which keeps BCC structure after suction-cast process and contains a low-Mo content, also exhibits dehydriding capacity of 2.3 wt%. The enthalpy change as well as dehydriding capacity of V-Free alloys obtained were similar to those reported V-based alloys. These findings are attractive for developing new V-free BCC hydrogen storage alloys and higher hydrogen capacity. Highlights: V maintains the stable single BCC structure but leads to more residual hydrogen. Mo substitution for V effectively alleviates the higher residual hydrogen to achieve a high dehydriding capacity of 2.5 wt%. Suction casting process was used to successfully prepare Ti–Cr–Mo BCC alloys with low Mo content. Kinetics and thermodynamics of Ti–Cr–Mo alloy upon de-/hydrogenation were calculated.