Transient and Failure Analyses of the Porous Zinc Electrode: II . Experimental

Abstract

Experiments were conducted to characterize behavior and failure mechanisms of porous zinc electrodes, prepared by pressing amalgamated zinc powder of particle size ranging from 250 to 325 mesh. The zinc test electrodes were disks with a cross‐sectional area of 1 cm2 and a thickness of 0.1 cm. Distribution of zinc and normalZnO , and electrode overpotentials were measured during galvanostatic discharge in 40 normalw/normaloKOH solution saturated with normalZnO . The observed reaction profiles were highly nonuniform and the reaction zone, located near the electrode surface, was very thin, typically 0.2 mm. The utilization of the present electrodes was very sensitive to the applied current density, initial porosity, amount of electrolyte, and the type of membrane. The measured reaction profiles and overpotentials were compared with the theoretical predictions of a recently developed mathmatical model. The agreement between observations and predictions provides a good interpretation of the discharge failure modes of negative zinc electrodes.

Multiscale Structured Particle‐Based Zinc Anodes in Non‐Stirred Alkaline Systems for Zinc–Air Batteries

“…[5,6] Dendritic deposits,aswell as passivation effects during the discharge processa re challenges arising from concentration depletion or oversaturationi nt he electrolytea nd the subsequent precipitation of zincate ions at the electrode.L ikewise, an unequal current distribution during operation induces an on-uniform distribution of the depositiono fz inc species. [7][8][9][10][11][12][13][14] It has been shown previously that the dissolutiono fz inc within the electrolyte induces an increaseo ft he density of the electrolyte.T his causes the zinc species to sink in the directiono ft he earthsg ravitational field. [3,15] Thep redominant current density has as ignificant influence on the deposition of the zinc species on the surface of the electrode.I ng eneral,l ow currents lead to uniform deposits of small crystals because the diffusional transport is high enough to balancet he consumptiono fz incate ions at the electrodes urface.H igh currents cause diffusion-limited depositions,w hich result in larger crystals and dendrite growth.…”

“…Dendritic deposits, as well as passivation effects during the discharge process are challenges arising from concentration depletion or oversaturation in the electrolyte and the subsequent precipitation of zincate ions at the electrode. Likewise, an unequal current distribution during operation induces a non‐uniform distribution of the deposition of zinc species . It has been shown previously that the dissolution of zinc within the electrolyte induces an increase of the density of the electrolyte.…”

Derivation of a local volume-averaged model and a stable numerical algorithm for multi-dimensional simulations of conversion batteries

“…Clark et al [6] review the current state of zinc-air battery modeling [7,8,9,10,11,12,13,14,15,16]. In our previous works on metal-air batteries [17,7,8,9,10,18], we show how to incorporate convection by a multi-component incompressibility constraint for concentrated solutions (see Eq.…”

A brief overview of secondary zinc anode development: The key of improving zinc-based energy storage systems

“…This type of zinc oxide may proceed via the nucleation and growth model 19 and/or via the adsorption model (Equation 4). [19][20][21][22] This compact ZnO layer passivates the zinc electrode, although its formation can be partially controlled by means of adjusting the discharge cell cutoff voltage or the depth of discharge (DoD). 20,23 ZnOH ads…”