High rate dischargeability of hydride electrode modified with magnetron sputtered MCrFeCoNi (M = V or Mn) coatings

Giemza, Agnieszka

doi:10.15199/40.2018.8.3

Cited by 1 publication

(3 citation statements)

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“…For the tested materials, the exchange current density increases with cycle number with an apparent tendency to settle on a constant level (≈120 mA∙g −1 ). The shape of measured dependences is similar to those we observed many times for different types of hydride electrodes [ 25 , 26 , 27 , 28 , 34 , 35 , 36 ].…”

Section: Resultssupporting

confidence: 87%

“…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%

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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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