Density and Viscosity Measurements of Zincate/KOH Solutions

Siu, S.

doi:10.1149/1.1837583

Cited by 11 publications

(13 citation statements)

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“…Therefore, the parameters represent this battery type. Decades ago, thermodynamics [64,57,65,66,67,68] and ionic transport [69,70,71,72,39,30,73,74,64,73,34,67,75,76] in the aqueous alkaline electrolyte (32 weight percent KOH) were accurately studied with experiments. We discuss the parameters in the Supplementary Materials A.…”

Section: Parameterizationmentioning

confidence: 99%

“…The sum includes ZnO for w 2 , but not for w 1 here because Siu et al define weight percent in two different ways [67]. The partial molar volume of the solvent is then determined from Eq.…”

Section: Acknowledgementmentioning

confidence: 99%

“…Appendix A.2.3. Multi-Phase Transport The dynamic viscosity η e of aqueous potassium hydroxide solutions is given by Siu et al [67] the permeability of the gas diffusion electrode at the initial saturations 0 = 0.63 is B e = 1 · 10 −14 m 2 [75]. Linear interpolating of the data in [76] yields the surface tension σ = 7.2252 · 10 −5 m 3 kg ρ e − 6.1263 · 10 −4 kg s 2 .…”

Section: Acknowledgementmentioning

confidence: 99%

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Modeling nucleation and growth of zinc oxide during discharge of primary zinc-air batteries

Stamm

Varzi

Latz

et al. 2017

Journal of Power Sources

104

145

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Metal-air batteries are among the most promising next-generation energy storage devices. Relying on abundant materials and offering high energy densities, potential applications lie in the fields of electro-mobility, portable electronics, and stationary grid applications. Now, research on secondary zinc-air batteries is revived, which are commercialized as primary hearing aid batteries. One of the main obstacles for making zinc-air batteries rechargeable is their poor lifetime due to the degradation of alkaline electrolyte in contact with atmospheric carbon dioxide. In this article, we present a continuum theory of a commercial Varta PowerOne button cell. Our model contains dissolution of zinc and nucleation and growth of zinc oxide in the anode, thermodynamically consistent electrolyte transport in porous media, and multi-phase coexistance in the gas diffusion electrode. We perform electrochemical measurements and validate our model. Excellent agreement between theory and experiment is found and novel insights into the role of zinc oxide nucleation and growth and carbon dioxide dissolution for discharge and lifetime is presented. We demonstrate the implications of our work for the development of rechargeable zinc-air batteries. Highlights• Modeling and simulating of VARTA button cell • Validation of galvanostatic discharge and lifetime analysis• Nucleation and growth of ZnO and its impact on discharge curve• Degradation due to carbonation of alkaline electrolyte (Birger Horstmann) promising candidates to fulfill this demand, because of their high specific energy density and the use of cheap and abundant materials. These batteries are open at the cathode and use atmospheric oxygen.Several metals, e.g., lithium, sodium, and zinc, are potential active anode materials in metal-air cells [1]. The high theoretical energy density of lithium-air batteries has stimulated a lot of research [2]. For aprotic electrolytes, the challenge is to influence growth mechanisms in order to maximize capacity, while maintaining sufficient reversibility [3,4,5,6,7,8,9]. Aqueous lithium-air batteries require a stable lithium conducting anode protection [10,11,12,13]. Non-aqueous sodium-air cells rely

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Section: Parameterizationmentioning

confidence: 99%

“…The sum includes ZnO for w 2 , but not for w 1 here because Siu et al define weight percent in two different ways [67]. The partial molar volume of the solvent is then determined from Eq.…”

Section: Acknowledgementmentioning

confidence: 99%

Section: Acknowledgementmentioning

confidence: 99%

See 1 more Smart Citation

Modeling nucleation and growth of zinc oxide during discharge of primary zinc-air batteries

Stamm

Varzi

Latz

et al. 2017

Journal of Power Sources

104

145

View full text Add to dashboard Cite

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“…At low zincate concentrations, a linear viscosity law is appropriate, i.e., ␣ϭ1, as demonstrated by Siu and Evans for dissolved zinc oxide concentrations up to 1 M. 7 In concentrated zincate solutions, Briggs et al have demonstrated a third-order relationship, or ␣ϭ3. 8 We have considered both cases here.…”

Section: Model Developmentmentioning

confidence: 98%

Electrohydrodynamic Impedance in the Presence of Nonuniform Transport Properties

Barton

West

2001

J. Electrochem. Soc.

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A numerical model is described for electrohydrodynamic impedance spectroscopy ͑EHDIS͒ in the presence of viscosity and diffusivity gradients near the electrode. The viscosity is assumed to depend on the concentration of a diffusion-limited reaction product raised to a power. An effective diffusion coefficient measured from a Levich analysis is shown to approach the nearsurface value of the diffusion coefficient when the near-surface kinematic viscosity is greater than in the bulk. Similarly, EHDIS measurements can lead to quick estimates of near-surface viscosity. The model is applied to interpret experimental data for the steady-state limiting current and electrohydrodynamic impedance of the zinc-KOH system.Mass transport limitations in electrode processes may lead to concentration gradients normal to electrode surfaces. For example, electrodissolution of metal anodes at the limiting current produces saturated or supersaturated concentrations of product salts or oxides near the electrode surface. Spatial variations in species concentration suggest that electrolyte properties such as density, viscosity, and diffusivity may vary in a similar manner. In general, it is necessary to account for such complexity when modeling these systems.Previous workers have considered the effect of spatial variations in fluid and transport properties near a rotating disk electrode. Newman showed that mass transfer to the electrode surface is uniform, even when nonuniformities are present, but found a strong effect on limiting current for copper deposition from aqueous CuSO 4 solution. 1 Pollard and Newman included variable physical properties in their analysis of steady-state silicon deposition to a rotating disk. 2 Barcia et al. have considered the effect of nonuniform viscosity on the electrohydrodynamic impedance spectroscopy ͑EHDIS͒ of masstransfer-limited dissolution of iron in aqueous iron sulfate solution. 3 In the latter study, an empirical viscosity profile was assumed, that was independent of the concentration profiles of dissolved species, and the fluid flow and mass transfer problems were solved separately.In a previous paper, experimental results were presented for mass-transfer limited zinc dissolution in KOH solutions. 4 EHDIS results were shown independent of disk rotation speed over a fourfold speed range. Moreover, electrochemical impedance spectroscopic ͑EIS͒ data were given in which no transport-limiting oxide film is detected. These results suggest that the phenomena controlling the EHDIS are confined to the electrolyte region. However, a simple model, in which fluid properties are assumed uniform, was unable to satisfy both the observed dependence of the steady-state limiting current on rotation speed and transient EHDIS measurements for realistic values of the bulk viscosity and diffusion coefficient. 4 In this paper, we consider the effect of nonuniform viscosity and diffusivity on steady-state and transient electrode response, and compare such a model to experimental results. The approach of Barcia et al. 3...

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“…with the capillary pressure p c . The corresponding transport parameters are given in the Supplementary Materials in Section S3 [59,11,60,61,62,63,64,65,66,67,68,30,69,60,70,59,58,10].…”

Section: Liquid Phase Transportmentioning

confidence: 99%

Zinc electrode shape-change in secondary air batteries: A 2D modeling approach

Schmitt

Arlt

Manke

et al. 2019

Journal of Power Sources

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Zinc-air batteries offer large specific energy densities, while relying on abundant and non-toxic materials. In this paper, we present the first multi-dimensional simulations of zinc-air batteries. We refine our existing theory-based model of secondary zinc-air systems. The model comprises thermodynamically consistent multi-species transport in alkaline electrolytes, formation and dissolution of metallic zinc and passivating zinc oxide, as well as multi-phase coexistence in gas diffusion electrodes. For the first time, we simulate zinc shape-change during battery cycling by modeling convection of zinc solids. We validate our model with in-situ tomography of commercial button cells. Two-dimensional volume-averaged simulations of cell voltage and zinc electrode morphology during discharge agree with these measurements. Thus, we can study how electrolyte carbonation limits shelf-life and how zinc shape-change limits cycle-life. The charging current is found to be the major contributor to cycle-life limitations. Finally, we optimize initial anode structure and charge-discharge protocols for improved performance and cycle-ability.

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Density and Viscosity Measurements of Zincate/KOH Solutions

Cited by 11 publications

References 0 publications

Modeling nucleation and growth of zinc oxide during discharge of primary zinc-air batteries

Modeling nucleation and growth of zinc oxide during discharge of primary zinc-air batteries

Electrohydrodynamic Impedance in the Presence of Nonuniform Transport Properties

Zinc electrode shape-change in secondary air batteries: A 2D modeling approach

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