Encapsulation of La1.5Mg0.5Ni7 nanocrystalline hydrogen storage alloy with Ni coatings and its electrochemical characterization

Dymek, Martyna; Nowak, Marek; Jurczyk, M.; Bala, H.

doi:10.1016/j.jallcom.2018.03.230

Cited by 30 publications

(16 citation statements)

References 36 publications

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“…Other authors reported nanometric nickel at AB 5 surfaces during charge‐discharge cycles in KOH solution . Some authors have also developed surface treatments with KOH and NaBH 4 for AB 5 alloys to favor this catalytic np‐Ni layer formation, or to produce nickel coatings on A 2 B 7 alloys . It is notable that this nickel layer was also observed in hydrides formed by solid‐gas route and its catalytic effect investigated by XPS .…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y₂Ni₇ for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

et al. 2019

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For the first time, the nickel layer formed during the corrosion of intermetallic alloys with a stacked structure has been isolated. This nickel layer has been produced by chemical dealloying of Y 2 Ni 7 through a corrosion process in alkaline medium. This anisotropic and nanoporous phase has been fully characterized regarding its morphology, chemical and structural properties, as well as its electrochemical behavior. The metallic phase is made of interconnected nanocrystalline cubic nickel, showing preferential orientation and nanopores. A cavity microelectrode has been used in addition to classical methods using bulk electrodes for electrochemical investigations of the layer. This full characterization is of primary importance to better understand the behavior of metallic anodes in Ni-MH batteries upon cycling and to ensure a longer lifetime.

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Section: Introductionmentioning

confidence: 99%

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y₂Ni₇ for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

et al. 2019

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“…Magnetron sputtering of thin, Ni-based layers on different HSM particles is more and more widely applied in the latest published reports [ 18 , 25 , 26 , 27 , 28 ]. Ni, similarly to Co and Fe, has well-documented catalytic properties toward H 2 O/H 2 redox system; therefore, the nickel-modified surface of HSMs improves material activation and increases the exchange current density of the hydrogen electrode [ 27 , 28 ].…”

Section: Introductionmentioning

confidence: 99%

“…As it has been mentioned, the multicomponent metallic coating should facilitate the maintaining of high specific capacities of the hydrogen storage substrate and reveal electrocatalytic properties to hydrogen sorption, and it should protect the active material particles (containing highly active lanthanum) against corrosion attack of aqueous, alkaline electrolyte. Among the constituents of the arranged HEA composition, Ni, Co, and Fe are responsible for catalytic behaviour [ 18 , 25 , 26 , 27 , 28 , 30 ], whereas Cr and Ti, due to their tendency to effective passivation of HSM [ 6 , 31 ], for corrosion resistance, and thus prolonged cycle life. The characteristics of changes in hydrogenation properties of hydrogen storage material by the amorphous layer of high-entropy TiCrFeCoNi alloy were accompanied by the morphology of the tested LaNi 4.5 Co 0.5 powders before and after the HEA modification process (SEM), the chemical composition (EDS), and phases analysis (XRD) of amorphous structure of the HEA coating.…”

Section: Introductionmentioning

confidence: 99%

Modification of Hydrogenation and Corrosion Properties of Hydrogen Storage Material by Amorphous TiCrFeCoNi HEA Layer

2022

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The effect of encapsulation of LaNi4.5Co0.5 powdered hydrogen storage material with ≈0.5 µm thick, magnetron-sputtered amorphous film of TiCrFeCoNi high-entropy alloy (HEA) on functional hydrogenation parameters of the hydride electrode is discussed. The multicycle galvanostatic charge/discharge tests carried out in deaerated, 6 M KOH solution allow for determining specific capacity decrease, exchange current density of the H2O/H2 system, and high rate discharge ability (HRD) of the hydride electrodes. Concentrations of individual constituents of the HEA in the particle coating determined by EDS analysis were practically the same (≈20 at.%) as in the applied TiCrFeCoNi target material. The XRD phase analysis pointed out the amorphous structure of the HEA coating. The presence of HEA coating decreases capacity by 10–15 per cent, but increases exchange current density for H2O/H2 system. The effect of HEA on capacity fade is ambiguous: low for 10–25 cycles (most probably due to effective corrosion inhibition) and distinct at long-term cycling (most probably due to galvanic effects resulting from mechanical degradation of particle surface). The presence of HEA coating considerably improves the HRD of the electrode material: for a discharge rate of 5C, the HRD coefficient becomes 4.6 times greater for HEA modified storage material.

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“…This material showed a great improvement in cyclability but poor hydrogenation kinetics due to its poor poisoning-resistance. Other improvements of the hydrogenation behaviour have been previously reported through surface protecting techniques such as microencapsulation [ 9 , 10 ], coating with metal oxides [ 11 ], and fluorination treatment [ 12 ]. All these techniques have high and low affinity for hydrogen and poisonous gases, respectively, but their limitations are not avoidable.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, the microencapsulation technique, which involves coating of the bulk alloy with 10 wt.% of Ni or Cu, utilises large amounts of the coating metal that is not responsible for hydrogen storage. It is also not economically favoured and produces heavy metal alloys [ 10 ]. On the other hand, surface modification through deposition of platinum group metals (PGMs), particularly palladium (Pd) which has a strong affinity for hydrogen, has been reported to possess relatively favourable and efficient improvement towards hydrogenation properties of alloy materials [ 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Improved Hydrogenation Kinetics of TiMn1.52 Alloy Coated with Palladium through Electroless Deposition

et al. 2021

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The deterioration of hydrogen charging performances resulting from the surface chemical action of electrophilic gases such as CO2 is one of the prevailing drawbacks of TiMn1.52 materials. In this study, we report the effect of autocatalytic Pd deposition on the morphology, structure, and hydrogenation kinetics of TiMn1.52 alloy. Both the uncoated and Pd-coated materials were characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). XRD analyses indicated that TiMn1.52 alloy contains C14-type Laves phase without any second phase, while the SEM images, together with a particle size distribution histogram, showed a smooth non-porous surface with irregular-shaped particles ranging in size from 1 to 8 µm. The XRD pattern of Pd-coated alloy revealed that C14-type Laves phase was still maintained upon Pd deposition. This was further supported by calculated crystallite size of 29 nm for both materials. Furthermore, a Sieverts-type apparatus was used to study the kinetics of the alloys after pre-exposure to air and upon vacuum heating at 300 °C. The Pd-coated AB2 alloy exhibited good coating quality as confirmed by EDS with enhanced hydrogen absorption kinetics, even without activation. This is attributed to improved surface tolerance and a hydrogen spillover mechanism, facilitated by Pd nanoparticles. Vacuum heating at 300 °C resulted in removal of surface barriers and showed improved hydrogen absorption performances for both coated and uncoated alloys.

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Encapsulation of La1.5Mg0.5Ni7 nanocrystalline hydrogen storage alloy with Ni coatings and its electrochemical characterization

Cited by 30 publications

References 36 publications

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y₂Ni₇ for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y₂Ni₇ for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

Modification of Hydrogenation and Corrosion Properties of Hydrogen Storage Material by Amorphous TiCrFeCoNi HEA Layer

Improved Hydrogenation Kinetics of TiMn1.52 Alloy Coated with Palladium through Electroless Deposition

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Encapsulation of La1.5Mg0.5Ni7 nanocrystalline hydrogen storage alloy with Ni coatings and its electrochemical characterization

Cited by 30 publications

References 36 publications

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y2Ni7 for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y2Ni7 for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

Modification of Hydrogenation and Corrosion Properties of Hydrogen Storage Material by Amorphous TiCrFeCoNi HEA Layer

Improved Hydrogenation Kinetics of TiMn1.52 Alloy Coated with Palladium through Electroless Deposition

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Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y₂Ni₇ for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries

Anisotropic Nanoporous Nickel Obtained through the Chemical Dealloying of Y₂Ni₇ for the Comprehension of Anode Surface Chemistry of Ni‐MH Batteries