Hydriding behavior of gas-atomized AB5 alloys

Bowman, R. C.; Witham, C.; Fultz, B.; Ratnakumar, B. V.; Ellis, Timothy W.; Anderson, Iver E.

doi:10.1016/s0925-8388(96)02929-5

Cited by 34 publications

(17 citation statements)

References 10 publications

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“…Low-cobalt alloys [12][13][14][15] have also been developed due to the high price of cobalt metal. Besides, some rapid solidification techniques [16][17][18], namely melt-spinning, high-pressure gas atomization, etc. have proved to be effective in improving the compositional homogeneity and microstructure of hydrogen storage alloys, which will be beneficial to the durability of alloy in alkaline solution.…”

Section: Introductionmentioning

confidence: 99%

Study of the high temperature characteristics of hydrogen storage alloys

et al. 2005

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 99%

Study of the high temperature characteristics of hydrogen storage alloys

et al. 2005

Journal of Alloys and Compounds

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“…In fact, several other metals turned out to be good candidates in lowering the plateau pressure. 2,9,[19][20][21] Nowadays, Mn is widely applied in commercial stoichiometric hydride-forming compounds. According to Notten et al, 9 compounds with nominal composition La(Ni 1-z Mn z ) x , in which the stoichiometry was varied in the range 5.0 ≤ x ≤ 6.0 have practically the same initial charge storage capacity.…”

Section: Introductionmentioning

confidence: 99%

Effect of partial substitution of nickel by tin, aluminum, manganese and palladium on the properties of LaNi5-type metal hydride alloys

Souza¹,

Ticianelli²

2003

J. Braz. Chem. Soc.

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Neste trabalho é feito um estudo do comportamento eletroquímico de eletrodos formados por pó de ligas de hidreto metálico do tipo AB 5 com formulações LaNi (5-x) Z x , onde Z é um elemento metálico que substitui parcialmente o Ni, que inclui Sn, Al, Mn e Pd. No caso do Mn, algumas estruturas do tipo AB 6 são também consideradas. A substituição de uma pequena fração do Ni pelo Al, Sn e Mn (x ≅ 0.3) promove um aumento da capacidade de armazenamento de hidrogênio (CAH), enquanto que o Pd leva à um decréscimo desta propriedade. Em geral todas as ligas apresentam alta CAH inicial, mas exibem baixa estabilidade. Foi observado que a diminuição da pressão de equilíbrio de hidrogênio em função do teor de Mn, nas ligas AB 5 , relaciona-se diretamente com o aumento do volume da cela cristalina unitária. Através de experimentos de impedância eletroquímica nota-se um aumento significativo da cinética de reação de hidretação/desidretação com o aumento do número de ciclos de carga/descarga do eletrodo, devido ao aumento da área ativa. Também foi observado que, no geral, as ligas que apresentam maior CAH são aquelas que possuem menor energia de ativação para a reação de oxidação de hidrogênio.This work reports studies on the electrochemical behavior of AB 5 -type hydrogen storage alloys, formed by LaNi (5-x) Z x , where Z is a metallic element partially replacing Ni, which included Sn, Al, Mn, and Pd. In the case of Mn, some AB 6 -type structures were also considered. Substitution of a small fraction of Ni by Al, Sn, and Mn (x ≅ 0.3) leads to an increase of the hydrogen storage capability (HSC), while for Pd there is a decrease of this property. Generally all alloys presenting larger initial HSC exhibit lower stability. A decrease of the hydrogen equilibrium pressure as a function of Mn content is observed for the AB 5 alloys and this is related to an increase of the crystalline unit cell volume. Electrochemical impedance measurements show a significant increase of the hydration/dehydration reaction kinetics due to a raise on the active area as a function of the charge/discharge cycle number. It is also seen that the alloys presenting larger HSC are those showing smaller activation energies for the hydrogen oxidation reaction.Keywords: hydrogen storage materials, electrode materials, energy storage materials, nickelmetal hydride battery IntroductionThe use of metal-hydride (MH) alloys as negative electrode material in rechargeable alkaline batteries has grown in recent years, because of its high energy density, high rate capability, and environmental acceptability. Ni-MH batteries have been developed and commercialized to meet a strong market demand as a power source with a high performance/cost ratio. 1,2 Currently, the anodes of most Ni-MH batteries are based on the AB 5 family of intermetallic compounds. To improve the electrode performance and lower costs of hydrogen storage alloys, AB 5 type alloys have been developed with substitution of pure earth elements in A side (La) by a mischmetal-based multicomponent and the parti...

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“…This form of the curve can indicate that the alloy forms two hydride modifications (a-phase and b-phase), as in the case of gas atomized LaNi 5 alloy powder [9]. The charge of the electrodes made from the fine-fraction alloy powder proceeds at a higher overpotential, and the discharge curve shifts in the direction of more negative potentials (about 0.04 V).…”

Section: Electrochemical and Storage Characteristicsmentioning

confidence: 92%