Geomag Mimetic Dynamically Reconfigurable POSS Framework Enables Antifatigue Solid Electrolyte Interphases for Lithium Metal Anodes

ABSTRACT Lithium metal anodes are fundamentally limited by mechanical fatigue and structural instability of the solid electrolyte interphase (SEI) during repeated plating and stripping. Here, we introduce a stress‐adaptive molecular interphase featuring autonomously reconfigurable ion‐transport channels inspired by modular “Geomag”‐like architecture. The interphase is constructed from polyhedral oligomeric silsesquioxane (POSS) nanocages bridged by reversible melamine‐mediated hydrogen bonds, forming dynamic secondary junctions that enable stress‐triggered disconnect–reconnect behavior. This reversible connectivity allows the SEI to dissipate local strain while actively opening and closing Li ⁺ transport pathways, thereby homogenizing ion flux and stabilizing the interfacial electric field. Antifatigue architecture effectively suppresses dendrite nucleation and prolongs interfacial stability. Symmetric Li || Li and Li || Cu cells verify enhanced reversibility, while Li || LTO full cells sustain ultralong cycling exceeding 2000 h. Pouch‐type lithium metal cells further demonstrate stable electrochemical performance under practical conditions. This work establishes a general molecular design paradigm for autonomously self‐regulating SEIs toward durable lithium metal cells.