Fast Iodine Conversion and Suppressed Polyiodide Shuttle Enabled by PEDOT Nanowires for Long-Cycling Zinc–Iodine Batteries

Aqueous rechargeable zinc–iodine batteries (ZIBs) have attracted tremendous attention in grid-scale energy storage. Nevertheless, their sluggish I – /I 0 conversion reaction kinetics and the severe polyiodide shuttles impede their practical applications. Herein, a cathode host comprising poly(3,4-ethylenedioxythiophene) nanowires and commercial Ketjen black (KB) is developed to address the above issues. The computational simulation of molecular electrostatic potential and experiment results reveal that the electrons transfer from the thiophene ring of PEDOT to neighboring I 2 molecules and PEDOT chains strongly interact with I 3 – species. These interactions jointly accelerate I – /I 0 conversion, lower reaction barriers, and suppress polyiodide formation and shuttles. Consequently, coin cell ZIBs with I 2 loadings of 13.1 and 1.7 mg cm –2 can stably operate for over 580 and 2300 cycles at 0.2 A g –1, respectively. A pouch cell employing the PEDOT-KB host with an I 2 loading of 5.8 mg cm –2 delivers a stable discharge capacity of 102 mAh g –1 over the 200 cycles. This work offers a facile yet effective strategy to design cathode hosts for shuttle-free high-performance ZIBs.