Phosphorus‐Induced Charge Redistribution and Lattice Self‐Regulation in Cu ₃ PSe ₄ Enables Low <i>N</i> / <i>P</i> Ratio and Durable Zn–I ₂ Batteries

ABSTRACT Zn–I 2 batteries is a promising large‐scale energy storage technology, yet conventional Zn metal anode faces challenges including corrosion, dendrite growth, and side reactions, hindering its practical application. Zn 2+ host anodes, leveraging the rocking‐chair mechanism and inherent polyiodide inertness, offer a potential solution to these issues. However, existing host anodes suffer from sluggish Zn 2+ kinetics and low capacity, limiting their compatibility with cathodes. Herein, we report a unique charge and lattice self‐regulation mechanism in Cu 3 PSe 4 that drives expedited Zn 2+ transport and high‐capacity performance. In this configuration, Cu 3 PSe 4 in situ decomposes to P and Cu 2 Se during initial cycling and Cu 2 Se provide subsequent capacity. Importantly, phosphorus modulates the Cu 2 Se lattice, inducing a transition from conventional contraction to expansion during Zn 2+ insertion, thereby enhancing ion transport kinetics and capacity simultaneously. Theoretical calculations reveal that P reconfigures the charge distribution and spatial configuration in Cu 2 Se, reducing Zn 2+ diffusion barrier. Consequently, the optimized Cu 3 PSe 4 anode delivers 150.5 mAh g −1 at 20 A g −1 , and the assembled Cu 3 PSe 4 ||I 2 cell achieves an exceptional lifespan of 30,000 cycles at 9 mg cm −2 with a low N/P ratio of 1.1, demonstrating superior stability. This work provides a novel system of corrosion‐resistant anode for high‐performance and metal‐zinc‐free zinc–iodine batteries.