Constructing dual interfacial gold nanodot interlayers in sandwich-structured BaTiO3/P(VDF-HFP) composites for high energy storage density

Polymer dielectrics characterized by high power density, fast discharge rate and reliability are critical in pulse energy storage systems. However, the low discharge energy density (Ud) of polymer dielectrics, stemming from the inverse coupling between dielectric constant (epsilon r) and breakdown strength (Eb), renders them insufficient to meet miniaturized requirements of modern electronics. To address this challenge, we propose constructing dual interfacial gold nanodot interlayers within a barium titanate (BT)/poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) trilayer composite (BT-3L) to synergistically enhance its epsilon r and Eb, ultimately achieving high Ud. Specifically, dual gold nanodot interlayers are anchored at the interface between the P(VDF-HFP) outer layer and the BT/P(VDF-HFP) middle layer via sputtering and hot-pressing processes. Benefiting from the interfacial polarization and Coulomb blockade effect induced by gold nanodots, the concurrently enhanced epsilon r of 12.9 at 10 kHz and Eb of 520.08 MV m-1 are achieved. Consequently, a significantly improved Ud of 14.78 J cm-3, which is approximately 176.4% that of the BT-3L composite (similar to 8.38 J cm-3), is further realized in this composite with dual gold nanodot interlayers. This work provides a promising approach for designing high-performance multilayer dielectric composites.