Hydrogen storage thermodynamics and dynamics of Mg–Y–Ni–Cu based alloys synthesized by melt spinning. (March 2020)

• Record Type: Journal Article
• Authors: Zhang, Yanghuan; Wei, Xin; Yuan, Zeming; Hou, Zhonghui; Qi, Yan; Guo, Shihai
• Is Part Of: Journal of physics and chemistry of solids. Volume 138(2020)
• Publication Date: 2020-03
• Subjects: A. Mg–Ni-Based alloy -- C. Activation energy -- C. Melt spinning -- C. Thermodynamics -- D. Hydrogen storage kinetics; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2019.109252
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: Excessive heat stability, poor kinetics of hydrogen absorption and desorption reaction are viewed as the major setbacks for the Mg-based hydrogen storing materials application. The microstructures of samples Mg25- x Y x Ni9 Cu ( x = 0, 1, 3, 5, 7) alloys were observed by XRD, SEM, and TEM. Besides, aiming at studying the characteristics of hydrogenation/dehydrogenation, the Sievert instrument, DSC and TGA were applied in the experiments. Substituting Mg with Y can promote the formation of the second phase YNi3 but does not transform the Mg2 Ni major phase. This substitution greatly prompts the amorphization. The increase of Y dosage triggers a mild decrease in the absolute values of Δ H and Δ S and remarkably boosts the improvement of dehydrogenation kinetics. Moreover, the increase in Y amount brings on a decrease in hydrogen absorption capability. The hydrogen desorption activation energy markedly lowers with increasing Y content (the E a de values of as-spun Y0 and Y3 samples are 71.38 and 66.13 kJ/mol, severally, and E k de values of them are 69.03 and 65.53 kJ/mol, respectively), which brings about the promotion of dehydrogenation kinetics of the experimental samples. Highlights: Mg–Y–Ni–Cu based alloys with nanocrystalline structures were fabricated by melt spinning. Substituting Y for Mg leads to the improvement of thermodynamic property. Increasing Y content brings about the promotion of dehydrogenation kinetics of the alloys. Substituting Y for Mg enables the steadiness of experimental hydride to decline.