Promoting effect of d-band center and in-situ precipitation strategy on sulfur evolution reaction

The slow conversion of polyphase in lithium-sulfur (Li-S) batteries not only intensifies the shuttle effect of lithium polysulfides (LiPSs), but also causes the continuous accumulation of inactive sulfur species, resulting in rapid capacity attenuation and sluggish dynamic performance. Herein, the promoting effect of atomic interface stress on sulfur reaction was investigated via CoFe-CoFe₂O₄ heterogeneous nanosheets with a cavity structure. The strain force induced by the in-situ precipitation of CoFe bimetallic alloy in oxide matrix increased the d-band center, which was conducive to the interaction between catalyst and LiPSs. The sulfur cathode based on this two-dimensional (2D) nanosheet design showed an extremely high capacity of 751 mAh g⁻¹ at 4 C. Even with a sulfur loading of 5.55 mg cm⁻², its area capacity was still as high as 7.15 mAh cm⁻². Meanwhile, the enhanced stability greatly improved the practical potential of Li-S batteries.