A Self-Deoxidizing Electrolyte Additive Enables Highly Stable Aqueous Zinc Batteries

In aqueous zinc (Zn) batteries, the Zn anode suffers from severe corrosion reactions and consequent dendrite growth troubles that cause fast performance decay. Herein, we uncover the corrosion mechanism and confirm that the dissolved oxygen (DO) other than the reputed proton is a principal origin of Zn corrosion and by-product precipitates, especially during the initial battery resting period. In a break from common physical deoxygenation methods, we propose a chemical self-deoxygenation strategy to tackle the DO-induced hazards. As a proof of concept, sodium anthraquinone-2-sulfonate (AQS) is introduced to aqueous electrolytes as a self-deoxidizing additive. As a result, the Zn anode sustains a long-term cycling of 2500 h at 0.5 mA cm(-2) and over 1100 h at 5 mA cm(-2) together with a high Coulombic efficiency up to 99.6 %. The full cells also show a high capacity retention of 92 % after 500 cycles. Our findings provide a renewed understanding of Zn corrosion in aqueous electrolytes and also a practical solution towards industrializing aqueous Zn batteries.

Automated summary

We uncover the corrosion mechanism in aqueous zinc batteries, and find that dissolved oxygen is the main cause of zinc corrosion and by-product precipitates. We propose a chemical self-deoxygenation strategy using sodium anthraquinone-2-sulfonate as a self-deoxidizing additive, which successfully solves the hazards caused by oxygen. The zinc anode exhibits a long-term cycling performance with high Coulombic efficiency and capacity retention. These findings are important for understanding zinc corrosion in aqueous electrolytes and industrializing aqueous zinc batteries.