Reversible aqueous Zn battery anode enabled by a stable complexation adsorbent interface

Abstract

Abstract Rechargeable aqueous Zn batteries (RAZBs) are highly promising for grid‐scale energy storage systems. Nevertheless, strong water molecule adsorption on Zn electrode provokes undesired corrosion reactions and electrode polarization/dendrite growth, restricting the reversibility of Zn anode and the commercialization of RAZBs. Herein, ethylenediamine tetraacetic acid (EDTA), a typical compounding ingredient, was applied in aqueous ZnSO4 electrolyte to replace the adsorbed water molecules on Zn surface and enabled a stable complexation adsorbent interface. The chemically adsorbed EDTA layer reduced the direct contact between H2O molecules and metallic Zn, and reduced the corrosion rate to more than a half. Moreover, such adsorbent interface featuring abundant oxygen/nitrogen‐based functional groups regulated Zn deposition kinetics and promoted the uniform Zn plating. As consequence, the stable complexation adsorbent interface enabled highly‐reversible Zn stripping/plating behavior for 5000 h under a harsh dynamic measurement that combining eletrochemical cycling at 1 mA cm−2 and 0.5 mAh cm−2 for 72 h and resting for 24 h. The effectiveness of such complexation adsorbent interface was also verified in MnO2||Zn full cells. The complexation interface chemistry demonstrated in this study opened up new avenues for the design of low‐cost and highly reversible Zn metal electrodes towards next‐generation RAZBs.

Keywords

• aqueous batteries
• electrochemical reversibility
• electrode/electrolyte interface
• electrolyte additive
• Zn anode