The Behavior of the Zinc Electrode in Alkaline Solutions: V . Supersaturated Zincate Solutions

Abstract

Light scattering, density, and viscosity data are presented for electrolytically prepared supersaturated zincate solutions that were allowed to decay naturally. The results indicate that the solute species in the supersaturated solutions are not completely different from those in saturated or unsaturated zincate solutions. An explanation for the formation and behavior of the supersaturated solutions is given based on various solute species that are formed by the reaction of OH− ions and H2O molecules with normalZnfalse(OH)2 and the subsequent formation of polynuclear zincate species. The rate and extent to which these are formed depends on the availability of OH− ions and unbound H2O molecules at the electrode surface.

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

“…[139][140][141][142][143][144][145][146][147] Dirkse suggested that Zn(OH) 4 2 or polynuclear species may exist in supersaturated zincate solutions and that the existence of these species depends on the availability of OH − and free H 2 O molecules in the electrolyte. [ 137 ] Peng studied the mechanism of zinc electroplating and suggested that Zn(OH) 2 became Zn(OH) ad by gaining one electron and then Zn(OH) ad was reduced to Zn by gaining a second electron. [ 141 ] Einerhand et al used a rotating ring disk electrode (RRDE) to determine the amount of hydrogen produced from the electrodeposition of zinc in alkaline solution and showed that hydrogen evolution increased with decreasing concentration of KOH and zincate.…”

Zinc Electrode Cycle-Life Performance in Alkaline Electrolytes Having Reduced Zinc Species Solubility

“…At high hydroxyl-ion concentrations the hydroxyl group is believed (Reichle et aI, 1975;Gubeli and Ste-Marie, 1967;Dirkse, 1981) to -5-2+ tetrahedrally complex the Zft ion, and the ove~all complex-formation reaction has the following equilibrium expression:…”

“…Dimers or polymeric forms of tetrahedrally complexed Zn have been proposed (Dirkse, 1981), but because of the effects of ionic strength on activity, the existence of these polymeric species cannot be predicted using Eq. (3).…”

“…Therefore the Zn(OH)2-saturated solution is -7-unstable and ZnO will precipitate, though slowly (Dirkse, 1981).…”

<i>Operando</i> X-ray Fluorescence Imaging for Zinc-based Secondary Batteries

“…Thus, it is suggested that the increased bright zone is attributable to the liquid phase with highly concentrated zinc species such as those in supersaturation. 11 High rate oxidation usually leads to fast passivation and solid zinc oxide formation, 12 however, in this intermediate state, soluble zinc species were observed in the system.…”