Electrocatalysts for Zinc-air Batteries Featuring Single Molybdenum Atoms in a Nitrogen-doped Carbon Framework.

Bifunctional catalysts can facilitate two different electrochemical reactions with conflicting characteristics. Here we report a highly reversible bifunctional electrocatalyst for rechargeable zinc-air batteries featuring a "core-shell structure" in which N-doped graphene sheets wrap around vanadium molybdenum oxynitride nanoparticles. Single Mo atoms are released from the particle core during synthesis and anchored to electronegative N-dopant species in the graphitic shell. The resultant Mo single-atom catalysts excel as active OER sites in pyrrolic-N and as active ORR sites in pyridinic-N environments. Zinc-air batteries with such bifunctional and multicomponent single-atom catalysts deliver high-power density (∼376.4 mW cm -2 ) and long-cycle life of over 630 h, outperforming noble-metal based benchmarks. Flexible zinc-air batteries that can tolerate a wide range of temperatures (-20 to 80°C) under severe mechanical deformation are also demonstrated. This article is protected by copyright. All rights reserved.