I3-/I- Redox Reaction-mediated Organic Zinc-Air Batteries with Accelerated Kinetics and Long Shelf Lives

The storage time of Zn-air batteries (ZABs) for practical implementation have been neglected long-lastingly. ZABs based on organic solvents promise long shelf lives but suffer from sluggish kinetics. Here, we report a longly storable ZAB with accelerated kinetics mediated by I-3(-)/I- redox. In the charge process, the electrooxidation of Zn-5(OH)(8)Cl-2 center dot H2O is accelerated by I-3(-) chemical oxidation. In the discharge process, I- adsorbed on the electrocatalyst changes the energy level of oxygen reduction reaction (ORR). Benefitting from these advantages, the prepared ZAB shows remarkably improved round-trip efficiency (56.03% vs. 30.97% without the mediator), and long-term cycling time (> 2600 h) in ambient air without replacing any components or applying any protective treatment to Zn anode and electrocatalyst. After resting for 30 days without any protection, it can still directly discharge continuously for 32.5 h and charge/discharge very stably for 2200 h (440 cycles), which is evidently superior to aqueous ZABs (only 0/0.25 h, and 50/25 h (10/5 cycles) by mild/alkaline electrolyte replenishment). This study provides a strategy to solve both storage and sluggish kinetics issues that have been plaguing ZABs for centuries, opening up a new avenue to the industrial application of ZABs.

Automated summary

A long-storable Zn-air battery with accelerated kinetics mediated by I-3(-)/I- redox is reported. The use of I-3(-) chemical oxidation accelerates the electrooxidation of Zn-5(OH)(8)Cl-2 center dot H2O in the charge process. In the discharge process, I- adsorption on the electrocatalyst changes the energy level of oxygen reduction reaction (ORR). The prepared ZAB exhibits significantly improved round-trip efficiency and long-term cycling time, making it a promising candidate for industrial applications.