Potassium-sulfur batteries attract tremendous attention as high-energy and low-cost energy storage system, but achieving high utilization and long-term cycling of sulfur remains challenging. Here we show a strategy of optimizing potassium polysulfides for building high-performance potassium-sulfur batteries. We design the composite of tungsten single atom and tungsten carbide possessing potassium polysulfide migration/conversion bi-functionality by theoretical screening. We create two ligand environments for tungsten in the metal-organic framework, which respectively transmute into tungsten single atom and tungsten carbide nanocrystals during pyrolysis. Tungsten carbide provide catalytic sites for potassium polysulfides conversion, while tungsten single atoms facilitate sulfides migration thereby significantly alleviating the insulating sulfides accumulation and the associated catalytic poisoning. Resultantly, highly efficient potassium-sulfur electrochemistry is achieved under high-rate and long-cycling conditions. The batteries deliver 89.8% sulfur utilization (1504 mAh g⁻¹), superior rate capability (1059 mAh g⁻¹ at 1675 mA g⁻¹) and long lifespan of 200 cycles at 25 °C. These advances enlighten direction for future KSBs development.

钾硫电池作为高能量、低成本的储能系统受到了极大的关注，但实现硫的高利用率和长期循环仍然具有挑战性。在这里，我们展示了优化多硫化钾以构建高性能钾硫电池的策略。通过理论筛选，我们设计了具有多硫化钾迁移/转化双功能的钨单原子和碳化钨复合材料。我们在金属有机框架中为钨创建了两种配体环境，它们在热解过程中分别转变为钨单原子和碳化钨纳米晶体。碳化钨为多硫化钾转化提供催化位点，而钨单原子促进硫化物迁移，从而显着减轻绝缘硫化物积累和相关的催化中毒。因此，在高倍率和长循环条件下实现了高效的钾硫电化学。该电池具有89.8%的硫利用率（1504 mAh g ^-1）、卓越的倍率性能（ 1675 mA g ^-1时为1059 mAh g ^-1）以及25°C下200次循环的长寿命。这些进展为未来 KSB 的发展指明了方向。