Ultra‐high power density in poly(arylene ether nitrile)‐based composites containing barium titanate and boron nitride nanosheets

Abstract Barium titanate (BT) nanoparticles were surface coated by a silane coupling agent (KH550) and core–shell structured nanoparticles (named KH550@BT) were obtained. Similarly, BT nanoparticles coated by polydopamine (PDA) were named as PDA@BT. Meanwhile, boron nitride (BN) nanosheets (BNNS) were successfully unstripped from block BN. Then, two kinds of ternary poly(arylene ether nitrile) (PEN)‐based composites are prepared using the solution casting method. Composites with 30 wt% KH550@BT and 12 wt% BNNS were named as KH550@BT/BNNS/PEN. Composites with 30 wt% PDA@BT and 12 wt% BNNS were named as PDA@BT/BNNS/PEN. The microstructure, dielectric properties, and energy storage properties of the ternary composites were studied in detail. PEN embedded with either BNNS or BT were prepared and studied for comparison. As a result, the introduction of BT will improve the dielectric constant ( ε r ) and energy storage density ( W ), but it will reduce the breakdown strength ( E b ) and charge–discharge efficiency ( η ) of composites. BNNS not only improves E b and W but also improves η of composites. Although the introduction of BT and BNNS simultaneously may reduce η , it will improve ε r , E b , and W of composites. Most importantly, the fast discharge speed and high power density demonstrate that the BT/BNNS/PEN composites are potential candidates to be used in high power pulsed capacitors fields. Highlights Boron nitride nanosheets improve the breakdown strength of composites. The composites achieve simultaneous increment of ε r and E b . The power density of the BT/BNNS/PEN composites was higher than 70 MW cm −3 .