Zinc–iodine (Zn–I₂) batteries are promising candidates for high-performance and cost-effective energy storage, yet their practical deployment is hindered by severe polyiodide shuttling and limited redox kinetics. To overcome this bottleneck at its core, a molecular-level fixation catalysis strategy—inspired by click chemistry principles is presented—that transcends the limitations of conventional adsorption and heterogeneous catalysis. Inspired by the selectivity and efficiency of click reactions, a Cp(Fe(CO)₂)₂-derived molecular catalyst (Fe-Cp) is designed that forms directional and robust Fe─I coordination bonds, locking iodine species into stable Fe-CpI complexes. Beyond anchoring, Fe-Cp uniquely enables axial electron transfer, facilitating reversible charge redistribution and dynamic iodine redox conversion beyond the reach of surface-confined systems. This dual-function mechanism not only suppresses the polyiodide shuttle but also dynamically regulates the electron redistribution at the catalytic interface, fundamentally enhancing reaction kinetics. Benefiting from this design, the Zn–I₂ batteries deliver an exceptional cycling lifespan of 63 000 cycles at 20 A g⁻¹ with 95% capacity retention and ≈100% Coulombic efficiency. Remarkably, even under a high mass loading of 20 mg cm⁻² in pouch Zn–I₂ cells, the system maintains a high areal capacity of 3.3 mAh cm⁻² and ≈100% capacity retention even after 2000 cycles.