Electron Bridge Effect Induced by Iodide Catalysis for Enhancing ZnS Activation in Aqueous Zinc–Sulfur Batteries

Iodide catalysis has currently been utilized to address sluggish reaction kinetics of ZnS activation in aqueous Zn–S batteries, but the detailed charge transfer mechanism remains unclear. Here, we develop a sulfur–vacancy ZnS (V s –ZnS) nanotubes as the cathode material for aqueous Zn–S batteries. The abundant electron–deficient Zn atoms can serve as Lewis acid sites to enhance I – adsorption. Spectroscopic characterization and theoretical calculations reveal that I–Zn–S moieties can act as an electron bridge to facilitate electron transfer from S sites to I sites, thereby promoting the breakage of Zn–S bonds and reducing the energy barrier of ZnS activation. The fabricated V s –ZnS cathode allows for a long-term Zn–S battery with a capacity fading of 0.042% per cycle after 1500 cycles at 2.0 A g –1, even enabling an areal capacity of 4.81 mAh cm –2 at a high ZnS loading of 17.50 mg cm –2 and a reversible specific capacity of 314 mAh g –1 at −20 °C.