Boosting oxygen reduction catalysis with abundant single atom tin active sites in zinc-air battery

Zinc (Zn)-air battery provides us an option to address both energy conversion and environment pollution issues. Herein, we successfully synthesized a type of Sn-N-C single atom catalyst and tailored the loading mass of single atom Sn. Sn1-N-C with the highest Sn loading mass exhibits the highest oxygen reduction reaction (ORR) activity (0.87 V vs. RHE for half-wave potential), near 4 e(-) selectivity, and excellent durability. Furthermore, Sn1-N-C based home-made Zn-air battery with a power density of 161 mW.cm(-2) at 250 mA.cm(-2) outperforms the one assembled from 20 wt.% Pt/C (63 mW.cm(-2) at 140 mA.cm(-2)) and shows superior stability (can last at least for 20 days until the overall consuming of 1 mm thick zinc plate), rendering it to be a promising alternative to replace noble metal Pt. The atomically dispersed Sn catalyzes ORR process via the 2 e(-) + 2 e(-) consequential pathway. This work potentially opens the door to provide valuable insights and principles for rational design of single atom Sn catalysts in Zn-air battery.