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

Abstract

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 (U_d) of polymer dielectrics, stemming from the inverse coupling between dielectric constant (ε_r) and breakdown strength (E_b), 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 ε_r and E_b, ultimately achieving high U_d. 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 ε_r of 12.9 at 10 kHz and E_b of 520.08 MV m⁻¹ are achieved. Consequently, a significantly improved U_d of 14.78 J cm⁻³, which is approximately 176.4% that of the BT-3L composite (∼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.