Water‐Trapping Single‐Atom Co‐N4/Graphene Triggering Direct 4e− LiOH Chemistry for Rechargeable Aprotic Li–O2 Batteries

Abstract

AbstractLithium–oxygen (Li–O2) batteries have received extensive attention owing to ultrahigh theoretical energy density. Compared to typical discharge product Li2O2, LiOH has attracted much attention for its better chemical and electrochemical stability. Large‐scale applications of Li–O2 batteries with LiOH chemistry are hampered by the serious internal shuttling of the water additives with the desired 4e− electrochemical reactions. Here, a metal organic framework‐derived “water‐trapping” single‐atom‐Co‐N4/graphene catalyst (Co‐SA‐rGO) is provided that successfully mitigates the water shuttling and enables the direct 4e− catalytic reaction of LiOH in the aprotic Li–O2 battery. The Co‐N4 center is more active toward proton‐coupled electron transfer, benefiting ‐ direction 4e− formation of LiOH. 3D interlinked networks also provide large surface area and mesoporous structures to trap ≈12 wt% H2O molecules and offer rapid tunnels for O2 diffusion and Li+ transportation. With these unique features, the Co‐SA‐rGO based Li–O2 battery delivers a high discharge platform of 2.83 V and a large discharge capacity of 12 760.8 mAh g−1. Also, the battery can withstand corrosion in the air and maintain a stable discharge platform for 220 cycles. This work points out the direction of enhanced electron/proton transfer for the single‐atom catalyst design in Li–O2 batteries.