HighlightsThe porous structure and interconnected conductive pathways accommodate a large amount of iodine, entrap polyiodides and guarantee its efficient utilization. While the Fe single atom catalyst efficiently catalyzes the iodine/polyiodide conversion.With “confinement-catalysis” host, the ZnǀǀI2battery delivers a high capacity of 188.2 mAh g−1at 0.3 A g−1, excellent rate capability with a capacity of 139.6 mAh g−1at 15 A g−1and ultra-long cyclic stability over 50,000 cycles with 80.5% initial capacity retained under high iodine loading of 76.72 wt%.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40820-023-01093-7.