Asymmetric Twist Molecule‑Mediated Local Electric Field Enabling Stable Zinc‑Iodine Batteries

ABSTRACT

Aqueous zinc‑iodine (Zn‐I ₂ ) batteries demonstrate significant potential for large‑scale energy storage, yet their practical application remains hindered by polyiodide shuttling at the cathode and uncontrolled Zn dendrite growth at the anode. In this work, an asymmetric twist molecule (ATM) was designed, which disrupts the equilibrium of molecular charge distribution and spatial steric effects. The rigid twist backbone locks the amino and carboxyl groups in a fixed orientation, generating a permanent molecular dipole that creates a stable local electrostatic field. This field adsorbs iodide ions, suppressing iodine hydrolysis and preventing polyiodide migration. Meanwhile, the oriented local electric field homogenizes the Zn ²⁺ flux and mitigates dendrite formation at the Zn anode, enabling uniform Zn deposition. Consequently, experimental results demonstrate that the Zn‐I ₂ battery delivers a reversible capacity of 235 mAh g ⁻¹ under a high loading of 7.3 mg cm ⁻² . Furthermore, the ATM containing Zn//Zn symmetric cell exhibits an ultralong cycling lifespan exceeding 6100 h at 1 mA cm ⁻² . This study proposes a feasible technical pathway for constructing highly stable aqueous Zn‐I ₂ batteries through the concept of asymmetric twist molecular design.