Effect of halides and alkali cations on the Zn(Hg)/Zn(II) electrode reactions

The kinetics, mass transfer, and surface roughness of zinc electrode in acidic zinc chloride solutions have been investigated in order to understand and optimize its performance in the zinc‐chlorine hydrate battery. Polarization and limiting currents were measured using a rotating hemispherical zinc electrode. Exchange current densities and Tafel slopes are reported and the cathodic zinc deposition is confirmed to be first order. A cathodic mechanism of two consecutive one‐electron transfer steps are postulated where the first step is the rate‐determining step. A diffusion coefficient of zinc ion in 0.05MZnCl2+1.0MnormalKCl , DZn2+=0.89×10−5 cm2/sec , is obtained from the kinetics‐diffusion mixed behavior. The surface roughness during the deposition depends strongly on the zinc‐chloride concentration, the fraction of the limiting current i/il , and the deposition time. Two regions are observed: (i) at appreciable fraction of the limiting current where the roughness is determined by the hydrodynamic conditions, and (ii) at well below the limiting current where the roughness is governed by the microthrowing power of the zinc deposit. The growth of zinc dendrites at the edges of a rotating disk electrode was investigated potentiostatically. After an initiation period the current increased sharply and dendrites were detected. The growth direction of the dendrites is explained in terms of the hydrodynamic flow and the level of zinc ion concentration.

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“…If the fractional coverage is assumed to approach unity, then Eq. [8] yields a Tafel slope be ----120 mV and a reaction order Z = 0. Thus, if Eq.…”

Section: (Ktk~ Exp [ --(1 --~)Fe I~ [Zn++] "R-t" ] [Ii]mentioning

confidence: 99%

“…Gaiser and Heusler (7) showed that zinc deposition is first order. Eriksurd (8) investigated the effect of halides and alkali cations on the Zn(Hg)/Zn(II) electrode reaction. Hulen and Eriksurd (9) studied the kinetics of the Zn(Hg)/Zn(II) electrode in acidic chloride solution.…”

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confidence: 99%

The Kinetics and Mass Transfer of Zinc Electrode in Acidic Zinc‐Chloride Solution

Kim

Jorné

1980

J. Electrochem. Soc.

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“…One is to extrapolate the exchange current from data at low concentrations such as the work of Hurlen et al [65,[71][72][73], where the io is three orders of magnitude smaller, the other is to measure the growth rate of a single, uniformly active surface such as the tip of a dendrite. The second method, used by Landau [48], yields an exchange current density of over 250 mA/cre 2. lt may overestimate the real value, however, since the ohmic drop is changing as the dendrite grows toward the counter electrode.…”

Section: Kinetics and Mechanisms Of The Zn+2/ Zn Electrode Reactionmentioning

confidence: 99%

Micro-scale mass-transfer variations during electrodeposition

Sutija¹

1991

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Electrochemistry of Zinc

Stroka

Maksymiuk

Galus

2006

Encyclopedia of Electrochemistry

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The sections in this article are Double‐layer Properties of Zinc Electrodes Pc ‐Zinc in Aqueous Solutions Zn Single Crystals in Aqueous Solutions Electrochemical Properties and Kinetics of the Zn ( II )/ Zn ( Hg ) and Zn ( II )/ Zn Systems Electrochemistry in Aqueous Solutions Electrochemistry in Water‐organic Solvent Mixtures Electrochemistry in Nonaqueous Solvents The Influence of Organic Compounds on the Electrode Processes The Electrochemical Properties of the Zinc Complexes Properties of Zinc Oxide Electrode Electrode Processes in Molten Salts Deposition and Underpotential Deposition of Zn on Solid Electrodes Underpotential Deposition of Zinc Zn UPD on Pt Zn UPD on Au Zinc Electrodeposition on Solid Electrodes Electrodeposition on Zn Electrodes Electrodeposition on Other Electrodes Passivation and Corrosion of Zinc Anodic Dissolution and Passivation of Zinc Corrosion Applied Electrochemistry Batteries Ni – Zn Cells Zn –Air Batteries Zn – Mn O 2 Batteries Zn – Ag Batteries Other Cells Electrowinning Zinc Electroplating Zinc Alloys Electroplating Electrochemical Sensors and Modified Electrodes Potentiometric Sensors Voltammetric/Amperometric Sensors Modified Electrodes

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Effect of halides and alkali cations on the Zn(Hg)/Zn(II) electrode reactions

Cited by 14 publications

References 58 publications

The Kinetics and Mass Transfer of Zinc Electrode in Acidic Zinc‐Chloride Solution

The Kinetics and Mass Transfer of Zinc Electrode in Acidic Zinc‐Chloride Solution

Micro-scale mass-transfer variations during electrodeposition

Electrochemistry of Zinc

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