Strain‐Adaptive Dielectric Metamaterials via Bioinspired “Ligament‐Bone” Architecture for Ultrahigh‐Energy Capacitive Storage

ABSTRACT Polymer dielectrics for capacitive energy storage face fundamental trade‐offs between breakdown strength, energy density, efficiency, and mechanical robustness. Herein, we break this paradigm by designing a bioinspired strain‐adaptive dielectric metamaterial with a multiscale “ligament‐bone” architecture. The “ligament” phase epoxy‐functionalized polyvinylidene fluoride‐based polymer provides dynamic constraints to suppress ferroelectric loss, while the “bone” units, alumina‐coated barium titanate nanocores (Al 2 O 3 @BaTiO 3 ), engineered with a strain‐responsive “periosteum” shell, mitigate interfacial distortion and carrier migration. This hierarchical design synergistically enables unprecedented electro‐mechanical properties: a record‐high energy density of 26.1 J cm −3 with 90.2% efficiency at 600 MV m −1 , coupled with a Young's modulus of 2.13 GPa. Operando characterizations and multiscale simulations reveal that strain‐adaptive reconfiguration of polymer chains and core‐shell interfaces dynamically optimizes field/charge distribution under extreme conditions. This biomimetic strategy establishes a universal framework for designing next‐generation dielectrics for extreme‐condition electronics.