High-entropy single-atom catalysts to accelerate polysulfide conversion kinetics in lithium-sulfur batteries

Single-atom catalysts (SACs) offer new possibilities to meliorate redox kinetics of lithium‑sulfur (Li-S) batteries due to their superior applicability in terms of atomic-scale reaction mechanisms and structure-activity relationships. However, introducing high entropy into SACs to design atomically dispersed materials with low symmetry and explore its application in Li-S batteries have not attracted widespread attention. Herein, five kinds of SACs and a quinary high-entropy SAC (HESAC) anchored on nitrogen-doped carbon nanocubes were synthesized by a one-step pyrolysis strategy. Electrochemical tests demonstrated that HESAC achieved excellent cycling stability and rate performance, which was mainly due to the synergistic catalytic effect of multi-metal sites in HESAC on lithium polysulfides, as confirmed by in situ ultraviolet visible spectroscopy. In addition, NiSAC revealed the highest catalytic activity among five SACs, indicating that the Ni atoms in HESAC played a leading role in promoting the conversion of lithium polysulfides. Combined with the adsorption ability study, it can be concluded that catalytic ability had a dominant influence on battery performance. This work proves that HESAC can effectively accelerate the sulfur conversion reaction kinetics, thus broadening the application of atomically dispersed catalysts with multiple compositions in Li-S batteries.