Atomic-Level Tin Regulation for High-Performance Zinc-Air Batteries

The trade-off between the performances of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) presents a challenge in designing high-performance aqueous rechargeable zinc-air batteries (a-r-ZABs) due to sluggish kinetics and differing reaction requirements. Accurate control of the atomic and electronic structures is crucial for the rational design of efficient bifunctional oxygen electrocatalysts. Herein, we designed a Sn-Co/RuO2 trimetallic oxide utilizing dual-active sites and tin (Sn) regulation strategy by dispersing Co (for ORR) and auxiliary Sn into the near-surface and surface of RuO2 (for OER) to enhance both ORR and OER performances. Both theoretical calculations and advanced dynamic monitoring experiments revealed that the auxiliary Sn effectively regulated the atomic/electronic environment of Ru and Co dual-active sites, which optimized the *OOH/*OH adsorption behavior and promoted the release of the final products, thus breaking the reaction limits. Therefore, the as-designed Sn-Co/RuO2 catalysts exhibited superb bifunctional performance with an oxygen potential difference (Delta E) of 0.628 V and negligible activity degradation after 200,000 (ORR) or 20,000 (OER) CV cycles. The a-r-ZABs based on the Sn-Co/RuO2 catalyst exhibited a higher performance at a wide temperature range of -30 to 65 degrees C. They demonstrated an ultralong lifespan of 138 days (20,000 cycles) at 5 mA cm-2, 39.7 times higher than that of Pt/C + IrO2 coupled catalysts at a low temperature of -20 degrees C. Additionally, they maintained an initial power density of 85.8% after long-term tests, significantly outperforming previously reported catalysts. More importantly, the a-r-ZABs also showed excellent stability of 766.45 h (about 4598 cycles) at a high current density of 10 mA cm-2.