Solvent-Free Dual In-Situ Interfacial Engineering of Polyester Composites for Enhanced Capacitive Energy Storage

Abstract

Molecular-level interfacial engineering has emerged as a pivotal strategy for simultaneously enhancing the dielectric constant and breakdown strength of polymer composites for capacitive energy storage. However, conventional fabrication methodologies, particularly those involving the utilization, removal, and recovery of organic solvents, incur substantial carbon emissions, conflicting with the global imperative of sustainable development. Herein, we propose a solvent-free, dual in-situ one-step synthesis strategy that integrates polyester condensation polymerization with inorganic crystal solvothermal synthesis. This approach facilitates the formation of an organic-inorganic hybrid interface phase, arising from extensive interdiffusion of polymer chains and inorganic components during the dual in-situ synthesis process. Importantly, this interface phase can be precisely tailored via in-situ modulation of inorganic phase growth, enabling molecular-level interfacial engineering. This unique interfacial architecture not only enhances the mechanical properties but also simultaneously elevates the dielectric constant and the breakdown strength. Concurrently, the hybrid interface effectively suppresses excessive electrical conduction, thereby minimizing energy losses. The resultant composite exhibits an exceptional energy density of 15 J cm⁻³ and a high efficiency of 85% at 100 Hz, far surpassing the performance metrics of current state-of-the-art linear polymer dielectrics. This work pioneers a scalable pathway toward the sustainable production of high-performance polyester-based composites.