Covalently modified and hierarchically structured corn-like BNNs@BT/benzoxazole composites with enhanced dielectric properties over an ultra-wide temperature range

Abstract

Polymer dielectric material is widely used in pulsed power technology and high-energy weapon systems. However, enhanced dielectric constant of polymer is accompanied by suppressed breakdown strength with the addition of dielectric ceramic. Herein, we report an efficient method to prepare functional corn-like hybrids which consist of BaTiO3 nanowires (BT) and BNNs nanosheets based on surface modification and high temperature ceramization. It is demonstrated that the outer BNNs not only optimizes the intrinsic dielectric difference matching, but also effectively suppress the loss caused by carrier migration. Especially, an increasement for operating temperature is achieved with the help of the poly-p-phenylene benzobisoxazole (PBO). Under 4 wt% filling, the composites have the highest discharged energy density (Ud = 2.24 J cm−3). Meanwhile, it also has high charge and discharge efficiency (η = 85 %) and an ultra-wide temperature dielectric stability (25 ℃-200 ℃). This work provides a promising dielectric nanocomposite candidate for high temperatures applications.