Enhanced Catalytic Conversion of Polysulfide Using 1D CoTe and 2D MXene for Heat-Resistant and Lean-Electrolyte Li−S Batteries

Abstract The key to achieving high-power, high-energy, and high-level safety for Li–S batteries is to accelerate the polysulfide conversion via electrocatalysis. Herein, we develop a bifunctional electrocatalytic 1D-2D CoTe-MXene separator modifier for heat-resistant and lean-electrolyte Li−S batteries. This combination of multiple compositions and hierarchical architecture design improves the separator's thermal durability while also speeding up Li2S nucleation and decomposition. As a result, Li−S batteries with CoTe-MXene separators achieve the high discharge capacity of 1664 mAh g−1, excellent rate capability (905 mAh g−1 at 3 C), and long-term cyclability at 60 °C. More impressively, the battery can deliver a high areal capacity of 9.0 mAh cm−2 even at a lean electrolyte (3 µL mg−1) and a high temperature (60 °C), which is rarely achieved by traditional Li–S batteries.