Local Electric Field Microenvironment‐Induced Dynamic Spatial Confinement to Stabilize I <sup>+</sup> Toward High‐Mass‐Loading and Stable Zinc–Iodine Batteries
Liting Chen, Song Huang, Zhenfeng Feng, Zhenxin Lin, Haolong Huang, Minghui Ye, Yufei Zhang, Zhipeng Wen, Yongchao Tang, Xiaoqing Liu, Cheng Chao Li
Abstract
Abstract Four‐electron iodine conversion chemistry (I −/ I 2 /I + ) endows zinc–iodine batteries with competitive energy density. The stability of I + conversion relies on its interaction with sufficient nucleophilic species (e.g., Cl − , Br − ). However, under high iodine loading, nucleophilic species fail to afford sufficient coordination strength and number within thick iodine cathode to stabilize I + , thus compromising the high‐voltage plateau and capacity. Here, we effectively spatially confine nucleophilic species (Cl − ) on the cathode by ─C─N + ‐induced localized electric field (LEF) microenvironment in polyquaternary ammonium iodide (PDDA‐I). Spatial confinement maximizes Cl − concentration on the cathode ensuring highly reversible I 0 /I + conversion, even in the low‐concentrated ZnCl 2 addition and high iodine loading. Importantly, the dynamically regulated Cl − maintains a balance with iodine species at the ─C─N + sites during cycling, effectively limiting the shuttling effect of polyiodides. Consequently, even adopting a high iodine loading of 16.03 mg cm −2 , the PDDA‐I still maintains a distinct four‐electron‐conversion dual voltage plateau with a remarkable capacity of 4.97 mAh cm −2 . An impressive lifespan of 10 000 cycles is achieved at 12.6 mg cm −2 with a capacity decay of 0.0012% per cycle, exceeding conventional iodine cathodes by 20‐fold. This work provides an important reference for high‐performance four‐electron conversion zinc–iodine batteries at high iodine loading.