Single-Atom Catalyst Induced Amorphous Li2O2 Layer Enduring Lithium–Oxygen Batteries with High Capacity

Abstract

Aprotic lithium–oxygen batteries (LOBs) may deliver exceptionally high energy density but struggle to attain rapid reversibility and substantial capacity simultaneously, due to typical surface or solution-formed insulating solid Li₂O₂. Tuning the structure of Li₂O₂ to create a large-area amorphous layer on the cathode is predicted to overcome the multiperformance limitations. Here, an isolated nickel single atom to nitrogen-doped graphene as a cathode catalyst (Ni─NG SAC) for LOBs is presented via a green click-trapping strategy. Derived from the maximized exposure of atomic active sites of the cathode, the formation/decomposition mechanisms of Li₂O₂ are tailored, and a large area of thin Li₂O₂ amorphous film is achieved. The structure and functions of Ni─NG SAC are explored by theoretical computation and synchrotron radiational investigation. Consequently, the abundant Ni─N₄ sites enhance redox kinetics and stand out to deliver an impressive specific discharge/charge capacity of 24 248/17 656 mAh g⁻¹ at 200 mA g⁻¹, together with a long cycle life of over 500 cycles. This study contributes helpful insights to achieve high-capacity LOBs with long lifespans, by constructing unique single-atom catalysts to optimize the formation of amorphous discharge Li₂O₂ products.