Structural models for nickel electrode active mass

Cornilsen, Bahne C.; Karjala, P. J.; Loyselle, Patricia L.

doi:10.1016/0378-7753(88)80029-6

Cited by 77 publications

(78 citation statements)

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“…Presumably due to instrumental limitations, only the former peak has been previously reported. 32,34,36 Weak features, assigned in this work to second order transitions, are observed at ∼790 cm −1 and ∼1075 cm −1…”

Section: Resultsmentioning

confidence: 93%

Raman and Infrared Spectroscopy of α and β Phases of Thin Nickel Hydroxide Films Electrochemically Formed on Nickel

et al. 2012

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The present work utilizes Raman and infrared (IR) spectroscopy, supported by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to re-examine the fine structural details of Ni(OH) 2 , which is a key material in many energy-related applications. This work also unifies the large body of literature on the topic. Samples were prepared by the galvanostatic basification of nickel salts and by aging the deposits in hot KOH solutions. A simplified model is presented consisting of two fundamental phases (α and β)o fN i ( O H ) 2 and a range of possible structural disorder arising from factors such as impurities, hydration, and crystal defects. For the first time, all of the lattice modes of β-Ni(OH) 2 have been identified and assigned using factor group analysis. Ni(OH) 2 films can be rapidly identified in pure and mixed samples using Raman or IR spectroscopy by measuring their strong O−H stretching modes, which act as fingerprints. Thus, this work establishes methods to measure the phase, or phases, and disorder at a Ni(OH) 2 sample surface and to correlate desired chemical properties to their structural origins.

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Section: Resultsmentioning

confidence: 93%

Raman and Infrared Spectroscopy of α and β Phases of Thin Nickel Hydroxide Films Electrochemically Formed on Nickel

et al. 2012

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“…Two electrochemical cycles were identified in 1969, and four phases were proposed to explain the voltage differences in 1980 [5,10]. In 1988 and 1990 these four phases were shown to exhibit the same layer-type structure, and variations in empirical formulae were directly correlated with the nonstoichiometry and point defect structure [11,12].…”

Section: Introductionmentioning

confidence: 99%

“…However, Raman spectroscopic studies on electrode active mass have indicated that these four electrochemically active materials actually share a common, nonclosepacked crystal structure (with …ABBCCA… stacking). This common structure is indicated by the Raman spectral selection rules; these do not change during cycling [11,12]. Only the peak positions vary.…”

Section: Introductionmentioning

confidence: 99%

“…This structure should be called the γ structure (after the structure of the charged phase in the α−γ cycle [10]), and was confirmed by reanalysis of the γ phase powder XRD pattern [11]. This structure contrasts with the closepacked, β−phase structure (with …ABAB… stacking), which is electrochemically unstable under normal cycling conditions [5,11,12]. "Aging" active mass in concentrated Conversion in KOH Overcharge alkali transform it into the β−phase structure [5,11,12].…”

Section: Introductionmentioning

confidence: 99%

“…This structure contrasts with the closepacked, β−phase structure (with …ABAB… stacking), which is electrochemically unstable under normal cycling conditions [5,11,12]. "Aging" active mass in concentrated Conversion in KOH Overcharge alkali transform it into the β−phase structure [5,11,12]. These structural similarities and conversions or transformations are represented in a modified Bode diagram shown in equation 2.…”

Section: Introductionmentioning

confidence: 99%

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A nonstoichiometric structural model to characterize changes in the nickel hydroxide electrode during cycling

Srinivasan

Cornilsen

Weidner

2004

J Solid State Electrochem

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Experimental capacities and mass changes are recorded using an electrochemical quartz crystal microbalance during the first 9 charge and discharge cycles of nickel hydroxide thin films cycled in 3.0 weight percent (wt%) potassium hydroxide electrolyte.For the first time, the film capacities have been corrected for the oxygen evolution side reaction, and the data used as input into the point defect-containing structural model to track the changes that occur during short-term cycling. Variations in capacity and mass during formation and charge/discharge cycling are related to changes in the point defect parameters, thus providing a structural origin for the unique experimental variations observed here and often reported in the literature, but previously unexplained. Proton-, potassium-, and water-content vary in the active material during charge/discharge cycling. The observed capacity loss, or "capacity fade," is explained by incomplete incorporation of potassium ions in (or near) the nickel vacancy during charge, as additional protons are then allowed to occupy the vacant lattice site. The increase in water content during reduction parallels the expansion of the electrode that is well known during cycling. This result confirms the origin of the swelling phenomenon as being caused by water incorporation. The model and methodology developed in this paper can be used to correlate electrochemical signatures with material chemical structure.

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Nickel Hydroxides

McBreen¹

1998

Handbook of Battery Materials

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Structural models for nickel electrode active mass

Cited by 77 publications

References 5 publications

Raman and Infrared Spectroscopy of α and β Phases of Thin Nickel Hydroxide Films Electrochemically Formed on Nickel

Raman and Infrared Spectroscopy of α and β Phases of Thin Nickel Hydroxide Films Electrochemically Formed on Nickel

A nonstoichiometric structural model to characterize changes in the nickel hydroxide electrode during cycling

Nickel Hydroxides

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