Synergistic Interplay of Fe and Co Single‐Atom Sites Spatially Separated on g‐C 3 N 4 for Enhanced Electrochemical Performance in Li‐O 2 Batteries

ABSTRACT Developing single‐atom catalysts (SACs) with efficient atomic usage and well‐defined coordination environments is pivotal for addressing limitations in redox kinetics and durability in lithium‐oxygen (Li‐O 2 ) batteries. Herein, an efficient yet broadly applicable ball‐milling followed by pyrolysis approach for the synthesis of bi‐metal Fe, Co SACs supported on a graphitic carbon nitride (g‐C 3 N 4 ) matrix is proposed. The synthesis involves a top‐down approach, where Fe and Co metals are atomized and stabilized on g‐C 3 N 4 support, facilitating uniform distribution of isolated metal atoms while inhibiting aggregation. This approach promotes the formation of coexisting Fe‐N 4 and Co‐N 4 single‐atom sites anchored on distinct triazine units within g‐C 3 N 4 , where the Co‐N 4 sites serve primarily as electronic modulators of the Fe‐centred active sites. The electronic interplay between the Co and Fe‐N 4 sites within the g‐C 3 N 4 framework modulates the local electronic structure and optimizes the adsorption energetics of LiO 2 intermediates, thereby accelerating both the oxygen reduction reaction and oxygen evolution reaction. As a result, the resulting catalysts deliver enhanced discharge capacity, lower overpotential, and prolonged cycling stability in Li‐O 2 batteries. Overall, this work provides new insights into bi‐metal synergistic catalysis on g‐C 3 N 4 and highlights the critical role of active‐site engineering in governing Li‐O 2 battery performance.