Water-Trapping Single-Atom Co-N4/Graphene Triggering Direct 4e− LiOH Chemistry for Rechargeable Aprotic Li–O2 Batteries
Lithium–oxygen (Li–O 2 ) batteries have received extensive attention owing to ultrahigh theoretical energy density. Compared to typical discharge product Li 2 O 2 , LiOH has attracted much attention for its better chemical and electrochemical stability. Large-scale applications of Li–O 2 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-N 4 /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–O 2 battery. The Co-N 4 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% H 2 O molecules and offer rapid tunnels for O 2 diffusion and Li + transportation. With these unique features, the Co-SA-rGO based Li–O 2 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–O 2 batteries.
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