Modulating Electronic Environment and Coordination Structure of Ruthenium with Ultralow Loading Atomic Nickel toward Highly Reversible Li–O2 Batteries

Abstract The atomic‐scale catalyst has attracted growing interests with great potential for next‐generation energy storage systems, owing to its extremely high atomic utilization efficiency (≈100%) and superior catalytic activity. However, due to the lack of control over coordination environments and electronic density, it remains a significant challenge to precisely construct a redox‐active single‐atom site in electrochemical reactions. Herein, a direct bimetallic modification strategy is reported to modulate the electronic environment and coordination structure of ruthenium with ultra‐low loading atomic nickel (NiRu─N/rGO). Through a series of characterization (e.g., HAADF‐STEM and XAFS), it can be found the dispersed atomic nickel sites are immobilized on the ruthenium interface by forming the new chemical heteroatom bonds (Ni─Ru), which will further reduce the grain size, tune coordination structure and tailor the electronic state of ruthenium through the electron transfer and redistribution. Interestingly, the above elaborately designed Ni─Ru heterogeneous bimetallic catalyst can be expected to enhance the electrocatalytic reactivity at the cathode/anode sides of Li–O 2 battery (LOB) system, and the working mechanisms of above are revealed through the carefully designed in situ experiments and theoretical calculations. This work will provide a novel research paradigm for the design of high‐performance LOBs towards practical applications.