Aqueous zinc–iodine (Zn||I2) batteries exhibit significant potential for large-scale energy storage, but their reversibility and cycle stability remain considerable challenges due to the severe side reactions on Zn anode and the shuttle effects of polyiodide ions. Here, a ternary co-solvents electrolyte, including diethyl carbonate, ethyl acetate, and H2O, is developed to effectively address the above issues. Specifically, the multi-solvents cooperatively reconstruct the solvation structure of Zn2+ and disrupt the strong bonding between H2O, markedly suppressing the water-induced parasitic reactions and reducing the freezing point of the electrolyte. Meanwhile, the reduced H2O content in the hybrid electrolyte significantly inhibits the solubility of iodine and thus impedes polyiodide shuttling. Furthermore, theoretical simulations combined with operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) and X-ray photoelectron spectroscopy reveal that the OTf− anions will be profoundly reduced to produce a F-rich inorganic–organic solid electrolyte interphase layer (SEI) on the Zn surface under the synergistic effect of the solvent molecules, effectively suppressing the formation of Zn dendrites and anode corrosion caused by active H2O and polyiodide ions. Consequently, the Zn||I2 batteries demonstrate stable operational performance across an extended temperature range from −30 to 50 °C, achieving a maximum lifespan of 20 000 cycles.