Hydrogen-absorbing alloys for the NICKEL–METAL hydride battery

Geng, Mingming; Han, Jianwen; Feng, Feng; Northwood, Derek O.

doi:10.1016/s0360-3199(98)00020-2

Cited by 60 publications

(55 citation statements)

References 16 publications

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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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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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“…Among these types of alloys, V-based solid solution alloys are expected as a highly promising hydrogen storage materials due to their relatively high hydrogen storage capacity and the capability of absorbing and desorbing hydrogen reversibly under ambient conditions [1][2][3][4][5]. The hydrogenation and dehydrogenation property of the hydrogen storage alloys in alkaline electrolyte is very important for its electrochemical properties, including the activation property, electrochemical capacity, the high-rate discharge ability and cycling characteristics, etc.…”

Section: Introductionmentioning

confidence: 99%

Effect of AB5 alloy on Ti0.10Zr0.15V0.35Cr0.10Ni0.30 hydrogen storage alloy

2009

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The structure and electrochemical characteristics of melted composite Ti 0.10 Zr 0.15 V 0.35 Cr 0.10 Ni 0.30 ? x% LaNi 4 Al 0.4 Mn 0.3 Co 0.3 (x = 0, 1, 5) hydrogen storage alloys have been investigated systematically. XRD shows that though the main phase of the matrix alloy remains unchanged after LaNi 4 Al 0.4 Mn 0.3 Co 0.3 alloy is added, a new specimen is formed. The amount of the new specimen increases with increasing x. SEM-EDS analysis indicates that the V-based solid solution phase is mainly composed of V, Cr and Ni; C14 Laves phase is mainly composed of Ni, Zr and V; the new specimen containing La is mainly composed of Zr, V and Ni. The electrochemical measurements suggest that the activation performance, the low temperature discharge ability, the high rate discharge ability and the cyclic stability of composite alloy electrodes increase greatly with the growth of x. The HRD is controlled by the charge-transfer reaction of hydrogen and the hydrogen diffusion in the bulk of the alloy under the present experimental conditions. Keywords Composite alloy Á Hydrogen storage alloys Á V-based solid solution alloy Á Metal hydride electrode Á Electrochemical characteristicsList of symbols XRD X-ray diffraction SEM Scanning electron microscopy EDS Energy-dispersive spectrometer C max Maximum discharge capacity (mAh g -1 ) C n Discharge capacity at cycle number n (mAh g -1 ) S n Capacity retention at cycle number n C T Discharge capacity at certain temperature (mAh g -1 ) C 303 Discharge capacity at 303 K (mAh g -1 ) LTD Low temperature discharge ability HTD High temperature discharge ability HRD High-rate dischargeability C i Discharge capacity at different discharge rate (mAh g -1 ) C 60 Discharge capacity at both the charge/discharge current density of 60 mA g -1 (mAh g -1 ) DOD Depth of discharge (%) EIS Electrochemical impedance spectroscopy R ct Charge-transfer resistance (mX) I 0 Exchange current density (mA g -1 ) R Gas constant (J mol -1 K -1 ) T Absolute temperature (K) FFaraday constant (C mol -1 ) D Hydrogen diffusion coefficient (cm 2 s -1 )

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“…Current researches most concern on the first aspect of increasing the performance of the electrodes. In the past, various methods have been introduced to improve the performance of the anode and cathode electrode, such as mixture of various additive, alkaline or acid etching, ball-milling and micro-encapsulation [8][9][10][11][12][13][14][15]. Feng and Northwood have studied the properties of the MH electrode microencapsulated Cu, and they found that the microencapsulated electrode had higher exchange current density and better high-rate dischargeability compared with the untreated one [16,17].…”

Section: Introductionmentioning

confidence: 99%