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

Zn-I₂ 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. Zn²⁺ 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 Zn²⁺ kinetics and low capacity, limiting their compatibility with cathodes. Herein, we report a unique charge and lattice self-regulation mechanism in Cu₃PSe₄ that drives expedited Zn²⁺ transport and high-capacity performance. In this configuration, Cu₃PSe₄ in situ decomposes to P and Cu₂Se during initial cycling and Cu₂Se provide subsequent capacity. Importantly, phosphorus modulates the Cu₂Se lattice, inducing a transition from conventional contraction to expansion during Zn²⁺ insertion, thereby enhancing ion transport kinetics and capacity simultaneously. Theoretical calculations reveal that P reconfigures the charge distribution and spatial configuration in Cu₂Se, reducing Zn²⁺ diffusion barrier. Consequently, the optimized Cu₃PSe₄ anode delivers 150.5 mAh g^-1 at 20 A g^-1, and the assembled Cu₃PSe₄||I₂ 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.