Theory-guided optimization of coordination sites via d-band modulation for efficient single-atomic Li–S catalysis

Abstract

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 d-band 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.