# Sulfonated Cellulose Acetate Nanofibers Induced Zincophilic‐Hydrophobic Interface to Regulate Ion Transport for Long‐Lifespan Zinc‐Iodine Batteries

## TL;DR

This paper introduces a protective layer made of sulfonated cellulose acetate nanofibers to improve the performance and lifespan of zinc-iodine batteries.

## Contribution

The novel zincophilic-hydrophobic interface design using SCA nanofibers enhances ion transport and prevents battery degradation.

## Key findings

- The SCA nanofiber membrane reduces water activity and promotes Zn2+ desolvation.
- The membrane's electrostatic repulsion with polyiodide inhibits the shuttling effect.
- Zinc-iodine batteries achieved over 13,000 cycles with high capacity retention and reversibility.

## Abstract

Aqueous zinc‐iodine batteries (ZIBs) have attracted extensive attention due to their advantages of high theoretical specific capacity, abundant reserves, high safety, and low cost, while the Zn anodes are still suffering from dendrite growth, side reactions, and polyiodide corrosion, seriously affecting the service life of ZIBs. Herein, sulfonated cellulose acetate (SCA) nanofiber membrane with zincophilic‐hydrophobic property is constructed on the Zn anode as a protective layer by electrospinning to circumvent the above problems and achieve a stable Zn anode. Attributing to both the hydrophobicity and zincophilicity, the SCA nanofiber membrane not only reduces the activity of water but also promotes the Zn2+ desolvation. Moreover, negatively‐charged groups of the SCA nanofiber membrane cause electrostatic repulsion with polyiodide. Density functional theory calculations and COMSOL simulations further reveal that the SCA nanofiber membrane can tune the uniform 3D deposition behavior of Zn2+ by chemisorption and physical structure, respectively. The obtained ZIBs can achieve ultra‐long life span (> 13000 cycles) with high‐capacity retention (96.74%) and reversibility (average CE: 99.83%), demonstrating the reliability of our proposed strategy for achieving stable and high‐performance ZIBs.

Sulfonated cellulose acetate (SCA) nanofiber membrane with zincophilic‐hydrophobic property is constructed on the surface of the Zn anode by the electrospinning technique to tune the 3D deposition behavior of Zn2+ by chemisorption and micro‐sized physical structure. The negatively‐charged groups of SCA nanofiber membrane form an electrostatic repulsion force with polyiodide, which displays a certain inhibitory effect on the shuttling of polyiodide.