Orbital Hybridization in Dual-Atom Embedded Siloxene Accelerate Sulfur Redox Reactions for Lithium-Sulfur Batteries

Promoting the sulfur reduction reaction (SRR) is crucial for improving the working efficiency of the lithium-sulfur (Li-S) battery. Inheriting the advantages of single-atom catalysts (SACs), dual-atom catalysts (DACs) have emerged as promising candidates with more flexible catalytic sites and better catalytic effect. Siloxene, a new encouraging polar 2D material for sulfur cathode, can effectively stabilize bimetallic atoms during electrochemical cycling. Herein, a series of transition metal dual-atom embedded siloxenes (TM₁TM₂-DA) are constructed as the cathode in Li-S batteries via First-principal calculations. The superior catalytic performance of sulfur reduction and Li₂S oxidation reaction of FeNi-DA is screened as the optimal catalysis, in addition to prominent electronic conductivity and favorable adsorption energies to polysulfides. The redistribution of d-electron density caused by Fe-Ni orbital hybridization is the key to improve the catalytic activity. Furthermore, easily-obtained descriptors (D_c and L_s) are selected for efficiently screening TM₁TM₂-DA catalysts with low SRR barriers. This work sheds light on DACs activation mechanisms and provides an efficient pathway to design cathode in Li-S batteries.