Evaluation of the diffusion coefficient of the zincate ion using a rotating disk electrode

Pessine, Elisabete Jorge; Agostinho, Sílvia Maria Leite; Chagas, H C

doi:10.1139/v86-083

Cited by 15 publications

(14 citation statements)

References 11 publications

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“…However, charge screening alone is not sufficient to explain the high selectivity of Nafion for hydroxide over zincate. Although zincate is divalent while hydroxide is monovalent, zincate has a threefold larger hydrodynamic radius (0.34 nm, versus 0.11 nm for hydroxide), [ 36,37 ] resulting in a more diffuse charge. We believe that size‐based exclusion plays an equally important role and that the particularly high selectivity of NC‐Celgard stems from its lower wettability compared to bulk Nafion.…”

Section: Resultsmentioning

confidence: 99%

High Depth‐of‐Discharge Zinc Rechargeability Enabled by a Self‐Assembled Polymeric Coating

Arnot

Lim

Bell

et al. 2021

Advanced Energy Materials

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Zinc has the potential for widespread use as an environmentally friendly and cost‐effective anode material pending the resolution of rechargeability issues caused by active material loss and shape change. Here, a self‐assembled Nafion‐coated Celgard 3501 (NC‐Celgard) separator is shown to enable unprecedented cycle life of a Zn anode in alkaline electrolyte at high depth‐of‐discharge (DODZn). Using commercially relevant energy‐dense electrodes with high areal capacities of 60 mAh cm–2, Zn–Ni cells tested at 20% DODZn cells achieve over 200 cycles while 50% DODZn cells achieve over 100 cycles before failure. The 20% and 50% DOD cells deliver an average of 132 and 180 Wh L–1 per cycle over their lifetime respectively. Rechargeability is attributed to the highly selective diffusion properties of the 300 nm thick negatively charged Nafion coating on the separator which prevents shorting by dendrites and inhibits redistribution of the active material. Crossover experiments show that the NC‐Celgard separator is practically impermeable to zincate ([Zn(OH)4]2–), outperforming commercial Celgard, cellophane, Nafion 211 and 212 separators while still allowing hydroxide transport. This work demonstrates the efficacy of selective separators for increasing the cycle life of energy‐dense Zn electrodes without adding significant volume or complexity to the system.

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Section: Resultsmentioning

confidence: 99%

High Depth‐of‐Discharge Zinc Rechargeability Enabled by a Self‐Assembled Polymeric Coating

Arnot

Lim

Bell

et al. 2021

Advanced Energy Materials

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“…Moreover, diffusion coefficient of zincate ions in 4 M NaOH (containing 2-10 mM zincate, at 25°C) is reported to be 3.10 × 10 À 6 cm 2 s À 1 . [33] At higher concentrations of both zincate and electrolyte, the reported diffusion coefficient value is significantly lower, i. e. 0.99 × 10 À 6 cm 2 s À 1 in 9 M KOH containing 1.21 M zincate and 0.14 × 10 À 6 cm 2 s À 1 in 11.2 M NaOH containing 1.43 M zincate. [34] Even though Eqs.…”

Section: Resultsmentioning

confidence: 99%

“…These variations in diffusion coefficient value arise from presence of different combinations of zinc species coordinated to H 2 O, Cl − , and NH 3 in the mentioned environments. Moreover, diffusion coefficient of zincate ions in 4 M NaOH (containing 2–10 mM zincate, at 25 °C) is reported to be 3.10×10 −6 cm 2 s −1 [33] . At higher concentrations of both zincate and electrolyte, the reported diffusion coefficient value is significantly lower, i. e. 0.99×10 −6 cm 2 s −1 in 9 M KOH containing 1.21 M zincate and 0.14×10 −6 cm 2 s −1 in 11.2 M NaOH containing 1.43 M zincate [34]…”

Section: Resultsmentioning

confidence: 99%

Zinc Electrodeposition in Acetate‐based Water‐in‐Salt Electrolyte: Experimental and Theoretical Studies

Amiri

Bélanger

2021

ChemElectroChem

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Zinc electroplating has found applications in many fields. The chemical composition of the electrodeposition bath can have a great impact on the final coating quality and the economics of the process. In traditional aqueous electrolytes, zinc deposition competes with the hydrogen evolution and oxygen reduction reactions, which can lead to hydrogen embrittlement of the substrate as well as decrease in efficiency. Highly concentrated water-in-salt electrolytes can suppress these reactions significantly. Here, we show that electrodeposition of zinc with high efficiencies can be achieved using an acetate-based water-in-salt electrolyte at room temperature. Nucleation studies confirm that at potentials more negative than À 1.30 V vs. Ag/AgCl, the three-dimensional (3D) nucleation process becomes instantaneous, while at more positive potentials it is progressive. Using two of the most common nucleation and growth models, Scharifker-Mostany and Mirkin-Nilov-Heerman-Tarallo, nucleation parameters such as the nucleation rate constant and nuclei density are found, showing a good agreement between the two models.

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“…This result indicates that the actual ionic conductivity may be dependent on the interplay between the effective mesh size and the hydrodynamic radius of charge conducting ions. When ZnO particles are dispersed into an alkaline solution, zincate complexes (Zn(OH) 4 2− ) are formed with a thin electric dipole layer of the solvent attached to the complex surface which influences the Brownian motion of the particles in the medium . Pessine et al.…”

Section: Resultsmentioning

confidence: 99%

“…Pessine et al. reported that the “solvodynamic radii” of Zn(OH) 4 2− calculated from the Stokes‐Einstein equation had a range of values from 0.35 to 0.41 nm . For hydroxide ions, Roobottom et al.…”

Section: Resultsmentioning

confidence: 99%

Effects of Crosslinker Concentration in Poly(Acrylic Acid)‐KOH Gel Electrolyte on Performance of Zinc‐Air Batteries

Tran

Clark

Chung

et al. 2020

Batteries & Supercaps

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Zinc-air batteries (ZABs) using gel polymer electrolytes suffer from low energy efficiency and poor cyclability. This issue is not only associated with the air electrode, as early failure of the battery is often due to the Zn electrode. Here, the cycle life of ZABs using alkaline poly(acrylic acid) (PAA-KOH) as the electrolyte is shown to vary by changing its crosslinking density. For ZABs using hydrogel electrolytes, understanding the failure mechanism and optimization of the hydrogel composition are key to achieving better utilization of the Zn electrode and battery rechargeability. In addition, the effects of crosslinker concentration on rheological properties, sol-gel fraction, ionic conductivity, and water retention ability of the hydrogel are discussed. PAA-KOH gels with lower crosslinking concentrations are weaker, but they have higher conductivity and better water retention, whereas gels with higher crosslinking concentrations affect the diffusion of zincate ions and facilitate passivation of the Zn electrode, resulting in early failure of the battery.[a] T.

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Evaluation of the diffusion coefficient of the zincate ion using a rotating disk electrode

Cited by 15 publications

References 11 publications

High Depth‐of‐Discharge Zinc Rechargeability Enabled by a Self‐Assembled Polymeric Coating

High Depth‐of‐Discharge Zinc Rechargeability Enabled by a Self‐Assembled Polymeric Coating

Zinc Electrodeposition in Acetate‐based Water‐in‐Salt Electrolyte: Experimental and Theoretical Studies

Effects of Crosslinker Concentration in Poly(Acrylic Acid)‐KOH Gel Electrolyte on Performance of Zinc‐Air Batteries

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