Synchronizing multistep polysulfide redox kinetics on CeO2 tailored Co-N4 single atom catalyst

초록

The intrinsic kinetic mismatch in the multistep sulfur redox process fundamentally drives polysulfide shuttling, severely limiting the electrochemical performance of LSBs. Herein, we report a Co-NC@CeO2-x catalyst that integrates atomically dispersed Co-N4 sites with redox-active cerium oxide, enabling cooperative regulation of sulfur reduction kinetics. Strong metal-support interaction induces charge redistribution, rendering the Co centers more electron-deficient while increasing the Ce3 +/Ce4+ ratio in CeO2. Electrochemical analyses reveal that Co-N4 sites preferentially accelerate liquid-phase polysulfide conversion, leading to Li2S4 accumulation and kinetic imbalance. CeO2 functions as an interfacial kinetic regulator, electronically activating Co-N4 sites to accelerate solid-phase polysulfide transformation, rebalancing the multistep sulfur redox pathway. As a result, the assembled cell exhibits high-capacity performance (1012 mA h g−1 at 0.5 C) with prolonged cycling stability (0.03% decay per cycle for 1000 cycles at 1 C). In large-area pouch-cell configuration with high S loading (4 mg cm−2) under lean-electrolyte systems, remarkable capacity (1608 mA h g−1 at 0.1 mA cm−2) is obtained with excellent cyclic stability. © 2026 Elsevier B.V.

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