Synergistic Enhancement of Dielectric Polymers Through Fluorine Incorporation for Improved Energy Storage, Reduced Loss, and Enhanced Processability

Abstract Establishing a harmonious equilibrium between high energy storage, minimal energy loss, and exceptional processability presents a formidable challenge within the realm of dielectric polymers. To address this challenge, harnessing the characteristics of long‐chain side groups to enhance polarity and toughness, as well as the fluorine effect to improve insulation and efficiency, a random copolymer, poly(4‐fluorostyrene‐trifluoroethyl methacrylate) (P(FS‐3FEMA)), is successfully synthesized via copolymerization of fluorine‐containing monomers, namely 4‐fluorostyrene (FSt) and trifluoroethyl methacrylate (3FEMA). Experimental findings demonstrate that elongating side chains enhances polymer toughness, boosts polarization strength, and self‐healing capacity. Introducing fluorine atoms into side chains maintains toughness while marginally increasing polymer chain spacing, reducing relaxation loss induced by dipole reorientation under an applied electric field. Additionally, fluorine incorporation enhances electron capture, effectively reducing leakage loss and the likelihood of thermal and electrical breakdown. Ultimately, the copolymer exhibits exceptional performance, characterized by extraordinarily high energy storage (U_e = 18.3 J cm⁻³), minimal energy loss (efficiency exceeding 89%), and enhanced toughness (increased by over 112%). This study presents a novel approach that harnesses the fluorine effect to reconcile the conflicting requirements of high energy storage, minimal energy loss, and exceptional processability in polymer dielectrics.