Theory-guided Optimization of Coordination Sites Via D-Band Modulation for Efficient Single-Atomic Li–S Catalysis

Single-atomic moieties have readily stimulated widespread potential in lithium-sulfur (Li-S) electrochemistry. However, precise coordination atom tailoring remains an obstacle, impeding a priori design and activity management. Meanwhile, incisive understanding of coordination modulation pertaining to energy level structure and electron arrangement is still lacking. Herein, based on theoretical predictions, CoN3B moiety has been screened out among a series of CoN3X architecture (X = N, S, P, B, Se, or Te) with advanced ability to bind polysulfides and lower reaction barriers. The key roles of coordination sites in decreasing the d-band broadening, elevating the dband center and lowering the electron occupation of antibonding orbitals for efficient d-p orbital hybridization are proposed. Accordingly, the Li-S cell assembled with CoSA-NB as a self-supporting cathode delivers a specific capacity of 1259.5 mAh g-1 at 0.2 C and a negligible capacity decay of 0.045 % after 1800 cycles at 2.0 C. The rational selection of coordination sites and in-depth comprehending of catalytic roles offer valuable insights into the development of single-atomic Li-S catalysis.