Targeted Modular Design of Rollable Polymer Dielectrics for High Efficiency Energy Storage Under Harsh Condition

ABSTRACT For capacitive energy storage at elevated temperature and high electric field harsh conditions, robust polymer dielectric films are desired with excellent electrical‐thermal‐mechanical properties. However, the enhancement of the temperature resistance generally sacrifices the electric bandgap and impacts mechanical toughness. A four‐block molecular construction methodology is strategically proposed to simplify chemical structures to universal blocks that balances thermo‐mechanical properties, electrical breakdown, dielectric polarization, and loss performance. The novel target‐designed polymer dielectrics achieve high energy densities of 8.5 J/cm 3 at 150°C and 6.4 J/cm 3 at 200 °C with over 90% efficiency. The strain at break, a key feature that dominates the scale‐up processability, can reach 40%, which is much higher than the reported other lab‐made polymer dielectrics. Successful roll‐to‐roll fabrication of the large‐area film is thus achieved, while unreduced energy storage performance under harsh conditions is still maintained. Our four‐block modular design paradigm establishes a universal framework that bridges microscopic chemical characteristics with macroscopic multifunctional requirements, providing a transformative strategy to fully access the polymer design space and break long‐standing trade‐offs between critical material parameters.