Asymmetric Polarization Modulation of d–p Hybridization-Enhanced Bidirectional Sulfur Redox Kinetics with Heteronuclear Dual-Atom Catalysts

Lithium sulfur batteries (LiSBs) represent a highly promising avenue for future energy storage systems, offering high energy density and eco-friendliness. However, the sluggish kinetics of the sulfur redox reaction (SRR) poses a significant challenge to their widespread applications. To tackle this challenge, we have developed an efficient heteronuclear dual-atom catalyst (hetero-DAC) that leverages surface charge polarization to enhance the asymmetric adsorption of sulfur intermediates. This study investigates how asymmetric electronic redistribution of CoFe DACs modulates the d-p orbital hybridization with sulfur intermediates, revealing the mechanisms of moderate adsorption dynamics with enhanced catalytic performance. The dynamic switching between mono and dual adsorption sites, enabled by the heteronuclear polarized configuration, fine-tunes the orbital hybridization, boosting the bidirectional rate-determining steps, that is, the solid-solid conversion of Li₂S₂ to Li₂S and the reverse dissociation of Li₂S. Consequently, the thus-designed CoFe DACs cathode delivers impressive rate performance, achieving a high initial specific capacity of 703.9 mA h g^-1 at 3 C, with a negligible decay rate of only 0.031% over 1000 cycles, demonstrating sustained long-term cycling stability. This work bridges geometric configurations and electronic structures, elucidating the mechanisms of asymmetric trapping and conversion enabled by hetero-DACs and offering fresh perspectives for catalyst design in LiSBs and beyond.