Polyiodide Confinement by Starch Enables Shuttle‐Free Zn–Iodine Batteries

作者：Shaojian Zhang, Junnan Hao, Huan Li, Pengfang Zhang, Zu‐Wei Yin, Yu‐Yang Li, Bingkai Zhang, Zhan Lin, Shi‐Zhang Qiao · 发表于：Advanced Materials · 年份：2022 · DOI：10.1002/adma.202201716 · 被引用次数：444 · 研究领域：Advanced battery technologies research、Advanced Battery Materials and Technologies、Advanced Battery Technologies Research

Abstract Aqueous Zn–iodine (Zn–I 2 ) batteries have been regarded as a promising energy‐storage system owing to their high energy/power density, safety, and cost‐effectiveness. However, the polyiodide shuttling results in serious active mass loss and Zn corrosion, which limits the cycling life of Zn–I 2 batteries. Inspired by the chromogenic reaction between starch and iodine, a structure confinement strategy is proposed to suppress polyiodide shuttling in Zn–I 2 batteries by hiring starch, due to its unique double‐helix structure. In situ Raman spectroscopy demonstrates an I 5 − ‐dominated I − /I 2 conversion mechanism when using starch. The I 5 − presents a much stronger bonding with starch than I 3 − , inhibiting the polyiodide shuttling in Zn–I 2 batteries, which is confirmed by in situ ultraviolet–visible spectra. Consequently, a highly reversible Zn–I 2 battery with high Coulombic efficiency (≈100% at 0.2 A g −1 ) and ultralong cycling stability (>50 000 cycles) is realized. Simultaneously, the Zn corrosion triggered by polyiodide is effectively inhibited owing to the desirable shuttling‐suppression by the starch, as evidenced by X‐ray photoelectron spectroscopy analysis. This work provides a new understanding of the failure mechanism of Zn–I 2 batteries and proposes a cheap but effective strategy to realize high‐cyclability Zn–I 2 batteries.