Solvent-free dual in situ interfacial engineering of polyester composites for enhanced capacitive energy storage

Abstract

Molecular-level interfacial engineering has emerged as a key strategy to simultaneously enhance the dielectric constant and breakdown strength of polymer composites for capacitive energy storage. However, conventional fabrication methods, particularly those involving the use, removal, and recovery of organic solvents, result in substantial carbon emissions, posing a direct challenge to global sustainability goals. To address this critical issue, this study introduces sodium dodecylbenzene sulfonate (SDBS) to enable the tailored in situ growth of inorganic components through a solvent-free, dual in situ one-step synthesis strategy. This approach facilitates the formation of a hybrid interfacial phase via enhanced molecular-level interdiffusion between polymer chains and inorganic components. The resulting interfacial architecture not only improves mechanical properties but also concurrently increases the dielectric constant and breakdown strength. In addition, the hybrid interface effectively suppresses excessive electrical conduction, thereby reducing energy losses. The resultant composite achieves an exceptional energy density of 15.07 J cm⁻³ and a high efficiency of 85% at 100 Hz, significantly outperforming state-of-the-art linear polymer dielectrics. This work advances molecular-level interfacial engineering by enabling in situ control over the size of the inorganic phase, offering a scalable pathway toward the sustainable production of high-performance polyester-based composites.