Shear-Driven Structural Ordering Enables High Energy Density in Ferroelectric Polymer Capacitors

Abstract

Polymer film capacitors are fundamental to modern power electronics, yet low permittivity restricts their energy density. Although poly(vinylidene fluoride) (PVDF) possesses high intrinsic permittivity, stabilizing its polar structure remains thermodynamically challenging. Here, we report a scalable physical processing strategy to optimize PVDF-based films via a specialized shear-imposed coating methodology. By employing a micro-structured blade, we generate intense local shear flow fields that exert hydrodynamic tension to drive a coil-stretch transition. This process drives an α-to-β phase transition and templates the growth of oriented, polar-phase-rich crystal structures. Furthermore, we develop a stage-wise regulation strategy using binary solvents to orchestrate evaporation dynamics, effectively trapping these metastable shear-induced conformations before relaxation. Effective across the PVDF copolymer family, this method enables P(VDF-HFP) films to achieve a high energy density of 20.05 J/cm3, a 44% improvement over conventional casting. This work provides a general, non-chemical pathway for manufacturing high-performance functional polymers through multi-physical field synergistic regulation.