A Rechargeable Zn–Air Battery with High Energy Efficiency Enabled by a Hydrogen Peroxide Bifunctional Catalyst

Rechargeable alkaline zinc–air batteries (ZAB) hold great promise as a viable, sustainable, and safe alternative energy storage system to the lithium-ion battery. However, the practical realization of ZABs is limited by their intrinsically low energy trip efficiency, stemming from a large charge and discharge potential gap. This overpotential is attributed to the four-electron oxygen evolution and reduction reactions and their sluggish kinetics. Here, a new concept based on two-electron generation and consumption of hydrogen peroxide at the air electrode is introduced. The O₂/peroxide chemistry, facilitated by a newly developed Ni-based bifunctional electrocatalyst, enables fast peroxide generation/consumption, exceptional energy efficiency, high durability, and high capacity. Hence, this new design offers substantial progress toward the commercialization of high energy density metal–air batteries.