A Phosphorus-Positive Porous Aromatic Framework Enables Shuttle-Free Durable Zinc-Iodine Batteries.

Aqueous zinc-iodine (Zn-I2) batteries have the advantages of low cost, high specific capacity, and high energy density, but they face challenges like the shuttle effect of polyiodide intermediates and slow redox kinetics. Herein, the phosphorus-positive porous aromatic framework (PAF-182) is first proposed as the iodine cathode additive, which can capture and confine polyiodides due to the proper pore size and the unique P+ site on the backbone. Both experimental and theoretical studies reveal that the robust electrostatic interaction inhibits the shuttling effect of polyiodides and localizes the iodine redox reaction on the cathode, favoring rapid redox kinetics. As a result, the Zn-I2 batteries with PAF-182 deliver the high specific capacity of 227.2 mA h g-1 at 0.05 A g-1 and retain 80.35% capacity after 20000 cycles at 2 A g-1. This work paves the way for the application of porous aromatic frameworks in Zn-I2 batteries and the realization of next-generation high-performance Zn-I2 batteries.