Hierarchical carrier trapping engineering in all-organic composites for high-temperature dielectric energy storage

Abstract

Polymer dielectrics encounter significant limitations in high-temperature energy storage applications due to the exponentially increasing conduction losses that occur under simultaneous thermal and electrical stresses. To address this issue, this study proposes a solution-processable, sandwich-structured all-organic polymer composite film that strategically integrates wide-bandgap poly(vinylidene fluoride-hexafluoropropylene) (PVH) and high-permittivity poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorofluoroethylene) (PVTC) within a polyetherimide (PEI) matrix. Experimental characterization and simulation analyses reveal that the wide-bandgap filler and interlayer heterogeneous interfaces create hierarchical carrier traps and energy barriers, collectively suppressing both intra- and inter-layer carrier migration. This synergistic approach reduces conductive losses and enhances breakdown strength by about 25% at 150 °C. The optimized sandwich-structured film exhibits a high discharged energy density of 6.1 J cm⁻³, along with a charge/discharge efficiency of 89%, as well as stable energy storage characteristics over 50 000 charge–discharge cycles and self-healing capability. This work provides a generalizable design strategy for high-temperature dielectric polymers, demonstrating exceptional potential for large-scale manufacturing and application in harsh-environment energy storage systems.