Thermodynamic and kinetic parameters and high rate discharge-ability of the AB5-type metal hydride anode

Kaabi, Abbes; Khaldi, Chokri; Lamloumi, J.

doi:10.1016/j.ijhydene.2016.03.128

Cited by 20 publications

(6 citation statements)

References 31 publications

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“…Fe has been used as a low-cost supplement in AB 2 [15][16][17][18][19][20][21][22], AB 5 [23][24][25][26][27][28][29][30][31][32][33][34], and body-centered-cubic (bcc) [35][36][37][38][39][40] HAAs. However, the results of Fe incorporation in these HAAs have so far been inconsistent.…”

Section: Introductionmentioning

confidence: 99%

Fe-Substitution for Ni in Misch Metal-Based Superlattice Hydrogen Absorbing Alloys—Part 1. Structural, Hydrogen Storage, and Electrochemical Properties

Kim

Ouchi²,

Nei³

et al. 2016

Batteries

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The effects of Fe partially replacing Ni in a misch metal-based superlattice hydrogen absorbing alloy (HAA) were studied. Addition of Fe increases the lattice constants and abundance of the main Ce 2 Ni 7 phase, decreases the NdNi 3 phase abundance, and increases the CaCu 5 phase when the Fe content is above 2.3 at%. For the gaseous phase hydrogen storage (H-storage), Fe incorporation does not change the storage capacity or equilibrium pressure, but it does decrease the change in both entropy and enthalpy. With regard to electrochemistry, >2.3 at% Fe decreases both the full and high-rate discharge capacities due to the deterioration in both bulk transport (caused by decreased secondary phase abundance and consequent lower synergetic effect) and surface electrochemical reaction (caused by the lower volume of the surface metallic Ni inclusions). In a low-temperature environment (−40 • C), although Fe increases the reactive surface area, it also severely hinders the ability of the surface catalytic, leading to a net increase in surface charge-transfer resistance. Even though Fe increases the abundance of the beneficial Ce 2 Ni 7 phase with a trade-off for the relatively unfavorable NdNi 3 phase, it also deteriorates the electrochemical performance due to a less active surface. Therefore, further surface treatment methods that are able to increase the surface catalytic ability in Fe-containing superlattice alloys and potentially reveal the positive contributions that Fe provides structurally are worth investigating in the future.

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Section: Introductionmentioning

confidence: 99%

Fe-Substitution for Ni in Misch Metal-Based Superlattice Hydrogen Absorbing Alloys—Part 1. Structural, Hydrogen Storage, and Electrochemical Properties

Kim

Ouchi²,

Nei³

et al. 2016

Batteries

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“…This process refers to performance of several repetitive charge/discharge cycles necessary to obtain the highest discharge capacity. Consequently, the best performing electrodes are those that activate very quickly and have the highest discharge capacity 50–52 …”

Section: Resultsmentioning

confidence: 99%

Structural, morphological, and electrochemical properties of AB₅ hydrogen storage alloy by mechanical alloying

Dabaki

Khaldi

Elkedim

et al. 2021

Env Prog and Sustain Energy

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Mechanical alloying (MA) is one of the most promising methods in the development of intermetallic alloys and their scientific research. In this paper, elemental powder mixtures of Ca, Ni, and Mn of nominal composition CaNi5‐xMnx (with x = 0.3, 0.5, and 1) were elaborated by MA technique during different milling times (2–60 h). Structural, morphological, and electrochemical changes were investigated by X‐ray diffraction (XRD), scanning electron microscopy, and Ec‐Lab galvanostat, respectively. The XRD test indicated that each alloy has Ni and CaNi3 or CaNi5 phases. In addition, the particle size of the ground powders is decreased with increasing milling time. Furthermore, all alloys have a very high activation capacity, whereby the activation capacity can be fully realized during the first cycle. The results showed that the most significant value of discharge capacity for all alloys was 40 h.

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“…This process refers to the execution of a number of repetitive charge/discharge cycles required to achieve the highest discharge capacity. Therefore, the best performing electrodes are those that activate very quickly and have the highest discharge capacity [56][57][58].…”

Section: The Cycling Properties Of the Cani 47 Mn 03 Electrode By Galvanostatic Methodsmentioning

confidence: 99%

Phase structure and electrochemical characteristics of CaNi4.7Mn0.3 hydrogen storage alloy by mechanical alloying

Dabaki

Khaldi

Elkedim

et al. 2021

J Solid State Electrochem

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In this paper, we study systematically the effect of ball/powder weight ratio on the morphological, structural, and electrochemical properties of CaNi 4.7 Mn 0.3 powder alloy by mechanical milling. The CaNi 4.7 Mn 0.3 alloy powder is elaborated for an optimal milling time of 40 h with 8:1 and 12:1 ball/powder weight ratios. The X-ray diffraction (XRD) characterization shows that the CaNi 4.7 Mn 0.3 alloy powder is characterized by a nanocrystalline/amorphous crystallographic state and exhibits two major Ni and CaNi 3 phases irrespective of the ball/powder weight ratio. The CaNi 4.7 Mn 0.3 electrode activates rapidly in the first cycle regardless of the ball/powder weight ratio, and the best value of maximum discharge capacity is obtained for an 8:1 ratio (125 mAh g −1 ). The values of diffusion coefficient/mean grain size squared ratio D H a 2 , Nernst's potential E 0 , and exchange current density I 0 at the first activation cycle are the best for 8:1 ball/powder weight ratio. After activation, the discharge capacity decreases exponentially regardless of the ball/powder weight ratio. Indeed, the capacity loss and the degradation rate after 50th cycle are about 71%, 10.71 cycle −1 and 53%, 2.95 cycle −1 for 8:1 and 12:1, respectively. The evolution of the D H a 2 ratio, E 0 , and I 0 during the cycling is in good agreement with that of the discharge capacity. The highest values of the diffusion coefficient D H , Nernst's potential E 0 , and exchange current density I 0 after 50th cycle are observed for 8:1 ball/powder weight ratio. KeywordsCaNi 4.7 Mn 0.3 hydrogen storage alloy • Mechanical alloying • Morphological and structural properties • Electrochemical properties

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Thermodynamic and kinetic parameters and high rate discharge-ability of the AB5-type metal hydride anode

Cited by 20 publications

References 31 publications

Fe-Substitution for Ni in Misch Metal-Based Superlattice Hydrogen Absorbing Alloys—Part 1. Structural, Hydrogen Storage, and Electrochemical Properties

Fe-Substitution for Ni in Misch Metal-Based Superlattice Hydrogen Absorbing Alloys—Part 1. Structural, Hydrogen Storage, and Electrochemical Properties

Structural, morphological, and electrochemical properties of AB₅ hydrogen storage alloy by mechanical alloying

Phase structure and electrochemical characteristics of CaNi4.7Mn0.3 hydrogen storage alloy by mechanical alloying

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Thermodynamic and kinetic parameters and high rate discharge-ability of the AB5-type metal hydride anode

Cited by 20 publications

References 31 publications

Fe-Substitution for Ni in Misch Metal-Based Superlattice Hydrogen Absorbing Alloys—Part 1. Structural, Hydrogen Storage, and Electrochemical Properties

Fe-Substitution for Ni in Misch Metal-Based Superlattice Hydrogen Absorbing Alloys—Part 1. Structural, Hydrogen Storage, and Electrochemical Properties

Structural, morphological, and electrochemical properties of AB5 hydrogen storage alloy by mechanical alloying

Phase structure and electrochemical characteristics of CaNi4.7Mn0.3 hydrogen storage alloy by mechanical alloying

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Structural, morphological, and electrochemical properties of AB₅ hydrogen storage alloy by mechanical alloying