Annealing treatment of AB2-type hydrogen storage alloys: II. Electrochemical properties

Zhang, Q.A; Lei, Yongquan; Yang, Xiaoguang; Ren, Keke; Wang, Q.D

doi:10.1016/s0925-8388(99)00486-7

Cited by 22 publications

(13 citation statements)

References 8 publications

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“…9. The DSC curves also confirm that the ZrMn 0.5 Ni 1.5 sample behaves much differently as Table 2 Mater Renew Sustain Energy (2013) In the present Zr-Mn-Ni alloy system, the hydrogen capacity of C14 phase is, in general, higher than the capacity of C15 phase, which is contrary to the observation of some earlier reports [21,26,27]. However, from performance point of view, particularly for low temperature desorption, C15 phase co-existing with the non-laves phase of Zr 7 Ni 10 is found to be better.…”

Section: Hydrogen Storage Characteristicscontrasting

confidence: 56%

Effect of Ni concentration on the structural and hydrogen storage characteristics of Zr–Mn based laves phase system

Kumar

Pukazhselvan

Tyagi

et al. 2013

Mater Renew Sustain Energy

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The present communication reports the hydrogen storage characteristics of ZrMn 2-x Ni x laves phase hydrides. It is observed that promising hydrogen storage materials can be tailored when ''x'' is in the range of 1.5 B x C 1. The materials formed within this range reversibly store *2 to *3 H/F.U. under manageable operating conditions. The composition ZrMn 0.5 Ni 1.5 is found to absorb and desorb hydrogen under room temperature. The other two compositions ZrMn 0.75 Ni 1.25 and ZrMnNi absorb *3.6 H/F.U. and release *3 and *3.2 H/F.U., respectively. In each case, almost half of the effective storage capacity of total can be reversibly stored within 5 s under room temperature. Therefore, the materials falling within the range of 1.5 B x C 1 are promising candidates for stationary device applications. The correlation between the compositions, structural-microstructural features and thermodynamic data are presented.

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Section: Hydrogen Storage Characteristicscontrasting

confidence: 56%

Effect of Ni concentration on the structural and hydrogen storage characteristics of Zr–Mn based laves phase system

Kumar

Pukazhselvan

Tyagi

et al. 2013

Mater Renew Sustain Energy

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“…After annealing, the ZrNi secondary phase in the C15 alloy becomes undetectable. This reduction/diminishing of the secondary phase after annealing also occurs in the C14 AB 2 MH alloys [55,61,71,72]. In addition to C14 and TiNi, there is also a 5.2 wt % of C15 found in the C14 alloy since the alloy's e/a (6.82) is close to the e/a at the C14/C15 threshold for Zr/Ti ( ∼ =1.8 (6.91)) [24].…”

Section: X-ray Diffractometer Analysismentioning

confidence: 84%

“…While only the un-annealed C14 alloy was used for this comparative work, two versions of the C15 alloys were assessed: pristine (C15) and annealed alloys (C15A). Since the effects of annealing on the multi-phase C14-predominated AB 2 MH alloys have been well studied (elimination/reduction in secondary phase abundance results in reduction of synergetic effects, leading to deterioration of electrochemical properties) [55,61,71,72], only the impacts of annealing on the C15 AB 2 MH alloy will be verified in this work. ICP results of the three alloys (C14, C15, and C15A) are in excellent agreement with the corresponding design values.…”

Section: Methodsmentioning

confidence: 99%

“…We hope this work would illuminate future AB 2 MH alloy research. 2 AM + Ann GP No difference if composition is the same [53] (ZrTi)(VMnNi)x AM EC C14 has a higher discharge capacity (x < 2) C15 has a better HRD (x > 2) [35,54] (ZrTi)(NiMnM) x , where M = Cr, V, Co, Al IM + Ann EC C15 has a better cycle life but slower activation [40] (ZrTi)(VMnCoNi) 2 LM EC C14 has a higher capacity and HRD [55] ( …”

Section: Introductionmentioning

confidence: 99%

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Comparison of C14- and C15-Predomiated AB2 Metal Hydride Alloys for Electrochemical Applications

Kim

Nei²,

Wan

et al. 2017

Batteries

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Abstract:Herein, we present a comparison of the electrochemical hydrogen-storage characteristics of two state-of-art Laves phase-based metal hydride alloys (Zr 21.5 (V and Cr) in the first composition results in an average electron density below the C14/C15 threshold ( e/a ∼ 6.9) and produces a C14-predominated structure, while the average electron density of the second composition is above the C14/C15 threshold and results in a C15-predominated structure. From a combination of variations in composition, main phase structure, and degree of homogeneity, the C14-predominated alloy exhibits higher storage capacities (in both the gaseous phase and electrochemical environment), a slower activation, inferior high-rate discharge, and low-temperature performances, and a better cycle stability compared to the C15-predominated alloy. The superiority in high-rate dischargeability in the C15-predominated alloy is mainly due to its larger reactive surface area. Annealing of the C15-predominated alloy eliminates the ZrNi secondary phase completely and changes the composition of the La-containing secondary phase. While the former change sacrifices the synergetic effects, and degrades the hydrogen storage performance, the latter may contribute to the unchanged surface catalytic ability, even with a reduction in total volume of metallic nickel clusters embedded in the activated surface oxide layer. In general, the C14-predominated alloy is more suitable for high-capacity and long cycle life applications, and the C15-predominated alloy can be used in areas requiring easy activation, and better high-rate and low-temperature performances.

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“…[17][18][19][20] In addition, the multicomponent alloys have the best electrochemical properties in the as-cast state. [21][22][23][24] Compared to annealed material, cast material generally contains a larger fraction of secondary minor phase(s) due to microsegregation (coring) of the primary phase(s) during dendrite solidification. Rapid solidification is often employed to reduce the level of coring and reduce or eliminate minor phases that are frequently not desired.…”

mentioning

confidence: 99%

Examination of Multiphase (Zr,Ti)(V,Cr,Mn,Ni)2 Ni-MH Electrode Alloys: Part I. Dendritic Solidification Structure

Boettinger¹,

Newbury²,

Wang³

et al. 2010

Metall Mater Trans A

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The solidification microstructures of three nine-element Zr-Ni-based AB 2 type C14/C15 Laves hydrogen storage alloys are determined. The selected compositions represent a class of alloys being examined for usage as an MH electrode in nickel metal-hydride batteries that often have their best properties in the cast state. Solidification is accomplished by dendritic growth of hexagonal C14 Laves phase, peritectic solidification of cubic C15 Laves phase, and formation of cubic B2 phase in the interdendritic regions. The B2 phase decomposes in the solid state into a complex multivariate platelike structure containing Zr-Ni-rich intermetallics. The observed sequence C14/C15 upon solidification agrees with predictions using effective compositions and thermodynamic assessments of the ternary systems, Ni-Cr-Zr and Cr-Ti-Zr. Experimentally, the closeness of the compositions of the C14 and C15 phases required the use of compositional mapping with an energy dispersive detector capable of processing a very high X-ray flux to locate regions in the microstructure for quantitative composition measurement and transmission electron microscope examination.

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Annealing treatment of AB2-type hydrogen storage alloys: II. Electrochemical properties

Cited by 22 publications

References 8 publications

Effect of Ni concentration on the structural and hydrogen storage characteristics of Zr–Mn based laves phase system

Effect of Ni concentration on the structural and hydrogen storage characteristics of Zr–Mn based laves phase system

Comparison of C14- and C15-Predomiated AB2 Metal Hydride Alloys for Electrochemical Applications

Examination of Multiphase (Zr,Ti)(V,Cr,Mn,Ni)2 Ni-MH Electrode Alloys: Part I. Dendritic Solidification Structure

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