Improved Electrochemical Performance of Zinc Anodes by EDTA in Near‐Neutral Zinc−Air Batteries

Abstract

The influence of ethylenediaminetetraacetic acid (EDTA) electrolyte additive on the performance of ZnÀ air batteries with nearneutral chloride-based electrolytes was examined for primary and secondary batteries. The electrochemical measurements indicated that Zn is not completely active in neat 2 M NaCl, but still could be discharged up to 1 mA cm À 2 around À 1.0 V Ag/AgCl . The characterization of the Zn surfaces revealed the existence of a passive film consisting of Simonkolleite, Zn(OH) 2 , and/or ZnO. The EDTA additive enhanced the discharge voltages by 200 mV to À 1.2 V Ag/AgCl indicating an active Zn surface. The effect of EDTA is explained by its chelation abilities with Zn 2 + before formation of hydroxide or oxide species. The ZnÀ air cells with EDTA were operated up to 930 h with specific energies up to 840 Wh kg Zn À 1 . The cells could also be cycled up to 70 cycles while providing enhanced discharge voltages at 1.15 V over 50 cycles. The positive effect of EDTA is dependent on the amount of free EDTA molecules. Nevertheless, the ZnÀ air cells showed better performance in terms of higher discharge voltage, discharge energies, and lower overpotentials in presence of EDTA.

Laboratory X-ray computed tomography imaging protocol allowing the operando investigation of electrode material evolution in various environments

“… 53 , 54 In such electrolytes, additives are also employed either to improve the Zn deposition behavior even more or to enhance the activity of Zn. 55 , 56 In this study, however, zw_07 and zw_01 , which were immersed in NaCl with the addition of glycine (near-neutral), still showed a tendency toward dendritic growth unless the applied current was very low (25 or 10 μA). This could be due to the insufficient concentration of the additive or its neutralization by the initial addition of the Zn into the electrolyte.…”

Modulating chelation with pH sensitivity for controlled structural defects and enhanced electrochemical and photocatalytic activities of LDH films

“…This difference is attributable to the strong chelation ability of Zn 2+ ions with EDTA molecules, leading to the creation of a more stable and long-lasting coating. 41,42 Consequently, this coating may effectively impede the inltration of corrosive ions, enhancing its corrosion resistance properties.…”

Low-Temperature and High-Performance Vanadium-Based Aqueous Zinc-Ion Batteries

“…Zn 2+ can only be deposited along the (002) crystal surface in the charge and discharge (GCD) process, greatly slowing down the growth of dendrites. 24,25 Merely solving the dendrite growth problem is not enough, so L-carnitine and sodium tartrate have also recently been used as electrolyte additives to improve the anodic HERs. 26,27 These additives are rich in hydroxyl, carboxyl, and other oxygen-containing functional groups, which can effectively regulate the solvated shell of Zn 2+ , thereby reducing the HERs caused by the decomposition of active H 2 O molecules.…”

“…The EDTA additive is also often used in the modification of electrolyte of AZIBs, the (100) crystal surface will generate a dissolution reaction when the Zn comes into contact with EDTA. Zn 2+ can only be deposited along the (002) crystal surface in the charge and discharge (GCD) process, greatly slowing down the growth of dendrites. , Merely solving the dendrite growth problem is not enough, so l -carnitine and sodium tartrate have also recently been used as electrolyte additives to improve the anodic HERs. , These additives are rich in hydroxyl, carboxyl, and other oxygen-containing functional groups, which can effectively regulate the solvated shell of Zn 2+ , thereby reducing the HERs caused by the decomposition of active H 2 O molecules . Therefore, designing an excellent electrolyte additive is attractive and challenging.…”