Stripping Voltammetry for the Real Time Determination of Zinc Membrane Diffusion Coefficients in High pH: Towards Rapid Screening of Alkaline Battery Separators

Abstract

An anodic stripping voltammetry (ASV) sensing platform which provides real time determination of zincate diffusion through membrane separators in alkaline electrolyte with total experimental times on the order of hours is presented. Advanced separators are essential for future rechargeable alkaline zinc batteries. In order to be screened, these membranes need to be evaluated for their zincate blocking performance. Current complexometric titration and elemental analysis methods for zincate membrane diffusion characterization can take days to weeks to obtain results as well as include large sample dilution factors and require additional sample processing. The anodic stripping voltammetry (ASV) sensing platform presented here provides real time determination of zincate diffusion in alkaline electrolyte with total experimental times on the order of hours. This method eliminates the need for sample dilution and post experiment sample processing. This technique significantly increases the throughput for the screening of advanced alkaline battery separators resulting in rapid turnaround times in the analysis of these vital membranes. To evaluate the utility of this method, zincate diffusion through commercial Celgard 3501 and Cellophane 350P00 was monitored using both ASV and inductively coupled plasma‐mass spectrometry (ICP‐MS) methods. The obtained zincate diffusion coefficients for both techniques were found to compare favorably.

Impact of Triethanolamine as an Additive for Rechargeable Alkaline Zn/MnO2Batteries under Limited Depth of Discharge Conditions

“…43 The H-cell was assembled with a separator (exposed area: 1.17 cm 2 ) placed between the feed and draw chambers. 30 mL of 8.5 M KOH with or without 10 vol% TEA was then added to the draw chamber of the H-cell.…”

Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry by Means of a Lead Mediator

“…The extension of an ASV method into highly alkaline environments could prove useful for the in situ electrolyte monitoring of alkaline batteries and fuel cells such that potential diagnostics of their performance vs. electrolyte composition could be realized . Such methods could also be adapted for the monitoring of alkaline leaching solutions used for the recovery and recycling of metal ions in these devices and other materials .…”

“…With this in mind, we recently extended the ASV method to highly alkaline (pH>14) electrolytes, in order to monitor Zn transport across alkaline battery separators . Successful analysis of Zn in alkaline electrolyte is thought to rely on the ability of the hydroxide to form soluble metal anion species with the analyte [e. g. zincate, Zn(OH) 4 2− ] as well as with the plating films [e. g. Bi(OH) 4 − ][8].…”

“…Here, the LOD for Cu in the presence of 5.0 ppm Pb was determined to be 0.67 ppm. Although, other elemental analysis techniques have lower LODs, ASV allows for in situ monitoring without sample dilution, thus the experimental LOD including dilution factors has been shown to be comparable to ICP‐MS and complexometric titration techniques .…”

“…In its place, less oxygen sensitive Bi film electrodes have been used successfully in slightly acidic buffered solutions [2][3][4]. These films have additional advantages such as low background currents, better reproducibility, as well as little need for electrode conditioning as compared to Hg electrodes [5].The extension of an ASV method into highly alkaline environments could prove useful for the in situ electrolyte monitoring of alkaline batteries and fuel cells such that potential diagnostics of their performance vs. electrolyte composition could be realized [6]. Such methods could also be adapted for the monitoring of alkaline leaching solutions used for the recovery and recycling of metal ions in these devices and other materials [7].With this in mind, we recently extended the ASV method to highly alkaline (pH > 14) electrolytes, in order to monitor Zn transport across alkaline battery separators [6].…”