The high performance of aqueous zinc–iodine batteries is limited by the soluble polyiodide shuttling and sluggish redox kinetics. Various strategies have been proposed to address these issues, but most of these optimizing strategies either add additional hurdles to the manufacturing process or require materials that are not currently commercially available. Herein, we take advantage of commercial 1,2-dimethyl-3-propylimidazolium iodide to serve as a redox reaction catalyst for the activation of iodine cathodes without any other material modification. Due to the strong bonding coordination between 1,2-dimethyl-3-propylimidazolium iodide and the polyiodides, the as-prepared cell has a high specific capacity (147 mA h g−1) at 50C, and ultralong cycling performance (20 000 cycles) with better capacity retention. This work introduces an effective and commercial material that enables bringing aqueous rechargeable zinc iodine batteries to the practical energy market.