Kinetics of the hydrogen evolution reaction in stoichiometric and non-stoichiometric hydrogen storage alloys for nickel-hydrogen batteries

Iwakura, Chiaki; Miyamoto, Masayoshi; Inoue, Hiroshi; Matsuoka, Makoto; Fukumoto, Yukio

doi:10.1016/0022-0728(96)04577-9

Cited by 12 publications

(5 citation statements)

References 11 publications

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“…fuses into the bulk of the alloy at a rate proportional to their concentration gradient. 17 In order to reduce the complexity of characterizing the kinetics of these reactions, it is assumed that hydrogen diffusion is sufficiently fast under certain conditions. Under steady-state conditions in the absence of an external current, i.e., when the Tafel reaction does not take place, 18 the configurational part of the chemical potential ( H ) of H ad is determined for an ideal, two-dimensional, randomly occupied surface lattice, by 19 [6] where o Had , R, T, and are the standard chemical potential of H ad , the gas constant, absolute temperature, and the fraction of the electrode surface covered by H ad , respectively.…”

Section: Theorymentioning

confidence: 99%

Relationship Between Equilibrium Hydrogen Pressure and Exchange Current for the Hydrogen Electrode Reaction at MmNi[sub 3.9−x]Mn[sub 0.4]Al[sub x]Co[sub 0.7] Alloy Electrodes

Senoh

Morimoto

Inoue

et al. 2000

J. Electrochem. Soc.

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Nickel-metal hydride (Ni-MH) batteries have attracted significant attention during the last decade because of their applications in consumer electronics, electric vehicles (EVs), and hybrid electric vehicles (HEVs). Research and development of the negative electrode materials are, however, still essential for further improvement of energy density, power density, and rate capability. 1,2 The exchange current (density), I 0 , for the hydrogen electrode reaction is one of the most important parameters for understanding electrode kinetics and is a measure of electrocatalytic activity of the negative electrode. The exchange current is influenced by changing the alloy composition, by mixing the alloy with other metals or oxides, or by adding chemical reducing agents to the electrolyte in order to activate the electrode surface. [3][4][5][6][7] Equations for the exchange current for metal hydride electrodes have been proposed by many research groups, and the electrode reaction mechanisms have been discussed extensively. 3,4,[8][9][10][11] Enyo and Maoka 8 investigated the detailed mechanism of the hydrogen electrode reaction by overpotential transients on a Pd hydrogen electrode and presented individual rates of the elementary steps and the activity of hydrogen adatoms on the electrode surface. Yayama et al. 9 proposed a simple theoretical model to describe the dependence of the equilibrium potential and exchange current on the hydrogen content of crystalline TiMn 1.5 H x . The experimental data could, however, only fit the model at low H content. Yang et al. 10 derived a modified model for this dependence and obtained several parameters, such as the equilibrium constant of the hydrogen transfer process, the maximum value of the storable hydrogen concentration, and the reaction order of the electrode reaction, from the fit of a model with no H-H interaction to Yayama's experimental data. Wakao and Yonemura 11 investigated the rate determining process in the electrode reaction on hydrogen-absorbing metal electrodes, such as LaNi 5Ϫx Al x , by anodic polarization measurements, and determined the charge-transfer coefficient for selected electrodes. Furthermore, one of the present authors 3,4 derived an expression for the exchange current involved in the electrochemical formation/decomposition process, by considering the influence of electrode blocking by adsorbed hydrogen.The equilibrium hydrogen pressure (P H2 ) is another important parameter for hydrogen storage alloys to predict the electrochemical discharge capacity of the negative electrodes because the capacity could be calculated from the hydrogen storage capacity (H/M) between P H2 ϭ 5 and 0.1 atm based on pressure-composition isotherm (PCT) curves at 45ЊC. 12 For high energy density and high power density of Ni-MH batteries, it is essential that the negative electrode material combines an appropriate plateau pressure with excellent electrocatalytic activity for the hydrogen electrode reaction. The purpose of the present study is to propose a theoretical model to d...

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Section: Theorymentioning

confidence: 99%

Relationship Between Equilibrium Hydrogen Pressure and Exchange Current for the Hydrogen Electrode Reaction at MmNi[sub 3.9−x]Mn[sub 0.4]Al[sub x]Co[sub 0.7] Alloy Electrodes

Senoh

Morimoto

Inoue

et al. 2000

J. Electrochem. Soc.

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“…Recently, many kinds of hydrogen storage alloys have been developed to be widely used as the negative electrodes for the Ni/MH battery [1][2][3] and new electrocatalysts for hydrogen evolution in alkaline water electrolysis. 4,5 It is well known that the performances of the hydrogen storage alloy electrodes and metal hydride ͑MH͒ electrodes are largely dependent on the alloy composition, [6][7][8] stoichiometric ratio x of the Mm͑B 5 ͒ x alloys, [9][10][11][12][13][14] surface properties of the alloys, [15][16][17][18][19][20] and environment temperature. [21][22][23] Until now, various electrochemical parameters in MH electrodes have been widely investigated [21][22][23][24][25] but only a few researchers [26][27][28][29] have reported the MH performances as a function of temperature.…”

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confidence: 99%

Effects of Temperature on the Performance of the MmNi[sub 3.6]Co[sub 0.7]Mn[sub 0.4]Al[sub 0.3] Metal Hydride Electrode in Alkaline Solution

Sequeira

Chen

Santos

2006

J. Electrochem. Soc.

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In the present study, the electrochemical and hydrogen transport kinetic performance of the MmNi3.6Co0.7Mn0.4Al0.3 metal hydride electrode has been systematically investigated in the temperature range 0–60°C . The results show that the electrode reaction becomes more reversible and gets faster at higher temperatures. At low-discharge current densities, the charge transfer overpotential is greater than the diffusion overpotential, whereas at high-discharge current densities the diffusion overpotential becomes dominant. At medium-discharge current densities, there is a mixed control with a predominance of the mass-transport conditions at lower temperatures. The calculated kinetic parameters also show that the hydrogen desorption on the metal hydride electrode is easier than the hydrogen absorption into its alloy bulk. Activation energies for charge transfer and for hydrogen diffusion, as well as the hydrogen diffusion coefficients in the electrode, have also been estimated.

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“…During cathodic polarization metals are exposed to changes in the structure of the surface as a result of the hydrogenation or surface formation of an alloy with the metals of the base electrolyte. P-and sp-electron structure metals do not dissolve hydrogen very well, whereas the d-electron Electrocatalysts for Hydrogen Energy structure metals are characterized by high affinity with hydrogen and absorb it during cathodic polarization [4,8,9].…”

Section: Metals and Their Alloysmentioning

confidence: 99%

Electrode Materials

Łosiewicz

Dercz

Popczyk

2015

SSP

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This review work was focused on conventional and modern electrodes which play an important role in electrochemical systems. Among many types of existing electrode materials, some of the most prominent materials from the conventional (metals and their alloys, graphite and mixed metal oxides) and the modern (amorphous, modified and composite) electrodes, have been outlined. What is also discussed is the recent intensive usability of nanocrystalline electrodes of better properties than their microcrystalline equivalents, and development trend of electrode materials.

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Kinetics of the hydrogen evolution reaction in stoichiometric and non-stoichiometric hydrogen storage alloys for nickel-hydrogen batteries

Cited by 12 publications

References 11 publications

Relationship Between Equilibrium Hydrogen Pressure and Exchange Current for the Hydrogen Electrode Reaction at MmNi[sub 3.9−x]Mn[sub 0.4]Al[sub x]Co[sub 0.7] Alloy Electrodes

Relationship Between Equilibrium Hydrogen Pressure and Exchange Current for the Hydrogen Electrode Reaction at MmNi[sub 3.9−x]Mn[sub 0.4]Al[sub x]Co[sub 0.7] Alloy Electrodes

Effects of Temperature on the Performance of the MmNi[sub 3.6]Co[sub 0.7]Mn[sub 0.4]Al[sub 0.3] Metal Hydride Electrode in Alkaline Solution

Electrode Materials

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