Conference Presentation (After Call)

FZJ-2026-00114

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Boosting Zinc Anode Activity in Near-Neutral Zinc-Air Batteries Through EDTA Electrolyte Additive

Durmus, Y. E. (Corresponding author)FZJ* ; Kungl, H.FZJ* ; Tempel, H.FZJ* ; Eichel, R.-A.FZJ*RWTH*

2025

Abstract: Metal-air batteries are emerging as a promising electrochemical energy storage technology, offering high theoretical energy densities and relying on cost-effective, safe, and abundant active materials. Among them, zinc-based metal-air batteries stand out for both primary and secondary applications. While primary zinc-air batteries (ZABs) are already commercially available for various uses, secondary ZABs face significant challenges, especially in alkaline environments. One potential solution is the use of aqueous neutral electrolytes, which help mitigate issues like electrolyte carbonization and dendrite formation. However, despite these advantages, neutral-electrolyte ZABs still struggle with performance limitations due to zinc surface passivation, the formation of insoluble zinc species, and corrosion.This study investigates the effect of ethylenediaminetetraacetic acid (EDTA) as an electrolyte additive on the performance of near-neutral secondary Zn-air batteries. The electrochemical behavior of Zn electrodes was analyzed in a 2M NaCl solution (pH 10) with and without EDTA. Open-circuit and potentiodynamic polarization experiments were first conducted to assess the corrosion parameters of Zn electrodes. Intermediate-term (24-hour) discharge experiments were then performed in a three-electrode cell setup under various current densities. The results indicated that in pure 2M NaCl electrolytes, Zn exhibited only partial activity, with discharge occurring primarily due to localized pitting. In contrast, the electrolyte containing EDTA enabled full Zn activity and significantly higher discharge potentials, highlighting its effectiveness in enhancing electrochemical performance.To further examine the dissolution behavior and discharge products, the electrode surfaces were analyzed using laser scanning microscopy (LSM), X-ray diffraction (XRD), and scanning electron microscopy (SEM) after discharge experiments. Additionally, the performance of full-cell Zn-air batteries was evaluated through galvanostatic discharge experiments (in primary mode) lasting up to 930 hours, achieving specific energies of up to 840 Wh/kgZn, and through galvanostatic cycling experiments (in secondary mode) lasting up to 575 hours with 70 cycles. The inclusion of EDTA in the electrolyte significantly improved specific energies and mass utilization efficiencies compared to pure electrolytes, demonstrating its potential as a promising additive for enhancing near-neutral Zn-air battery performance.

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Contributing Institute(s):

1. Grundlagen der Elektrochemie (IET-1)

Research Program(s):

1. 1223 - Batteries in Application (POF4-122) (POF4-122)
2. BMBF 03SF0627B - Verbundvorhaben iNEW2.0: In iNEW (Inkubator Nachhaltige Elektrochemische Wertschöpfungsketten) werden neuartige und leistungsfähige Elektrolyseverfahren zur Anwendung in nachhaltigen Power-to-X Wertschöpfungsketten erforscht und entwickelt (03SF0627B) (03SF0627B)

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