Ultrahigh-energy density polymer dielectrics via in-situ phase-regulated interfaces in electric-field-directed 3D printing

In-situ electric-field-directed 3D printing co-engineers molecular alignment, deep traps and interfacial barriers. • Achieves 30.5 J cm −3 energy density, >84.5% efficiency and 750 MV m −1 breakdown strength. • Novel multiscale charge-blocking mechanism couples H-bond deep traps with band bending to suppress injection. • Establishes a scalable design paradigm to break the polarization-breakdown-efficiency trade-off in polymer dielectrics. The inherent conflict between polarization and breakdown strength limits the development of high-energy-density polymer dielectrics with both high efficiency and reliability. Here, we report an electric-field-directed 3D printing strategy that creates in-situ phase-regulated interfaces in an all-organic composite of partially hydrogenated poly(vinylidene fluoride- co -chlorotrifluoroethylene) (PVCT) and hydrogenated poly(methyl methacrylate) (PMAA). By coupling in-situ electric poling with hydrogen-bond-assisted assembly, we construct a seamless integration of a surface charge-blocking layer, a bulk deep-trap network, and a highly oriented polar crystalline matrix. This multi-scale engineered dielectric overcomes the traditional polarization-insulation trade-off. It delivers an exceptional discharged energy density of 30.5 J cm −3 , an efficiency exceeding 84.5%, and a remarkable breakdown strength of 750 MV m −1 . The printed capacitor also demonstrates superior thermal stability and outstanding cycling endurance, retaining over 98.7% of its initial efficiency after 10,000 cycles. This work establishes a scalable manufacturing paradigm for designing high-performance polymer dielectrics, opening new avenues for next-generation energy storage and power electronics. In-situ phase-regulated interfaces via electric 3D printing overcome the polarization-insulation trade-off for ultrahigh energy density, efficiency, and stability in polymer dielectrics. Download: Download high-res image (178KB) Download: Download full-size image