Largely enhanced energy storage performance of sandwich-structured polymer nanocomposites with synergistic inorganic nanowires

Abstract It is of crucial importance to develop novel dielectric materials with high discharge energy densities to meet the urgent requirements in the rapid advances in modern electronics and electrical power systems. In this work, we describe a new class of sandwich-structured ceramic-polymer nanocomposites base on poly(vinylidene fluoride-co-hexafluoropropylene) exhibiting outstanding energy storage performance. The central layer of the composite consists of MgO nanowires to offer high breakdown strength, whereas the outer layers contain BaTiO3 nanofibers to provide improved dielectric constant of the composites. The systematic investigation gave the composites with 2 wt% MgO in the central layer and 20 wt% BaTiO3 in the outer layers to yield the best energy density of 15.55 J cm−3 with a charge-discharge efficiency of 68% at the Weibull breakdown strength of 416 MV m−1. It is found that the trilayered nanocomposite exhibits superior energy storage performance as compared to the corresponding single-layered composite films. The result demonstrates the uniqueness of the layered structure to incorporate multiple inorganic components into polymer with enhanced collective properties for energy applications.