High-temperature energy storage dielectric with inhibition of carrier injection/migration based on band structure regulation

Dielectric capacitors have a high power density, and are widely used in military and civilian life. The main problem lies in the serious deterioration of dielectric insulation performance at high temperatures. In this study, a polycarbonate (PC)-based energy storage dielectric was designed with BN/SiO₂ heterojunctions on its surface. Based on this structural design, a synergistic suppression of the carrier injection and transport was achieved, significantly improving the insulating properties of the polymer film. In particular, the composite film achieves optimal high-temperature energy-storage properties. The composite film can withstand an electric field intensity of 760 MV m⁻¹ at 100°C and obtain an energy storage density of 8.32 J cm⁻³, while achieving a breakthrough energy storage performance even at 150°C (610 MV m⁻¹, 5.22 J cm⁻³). Through adjustment of the heterojunction structure, free adjustment of the insulation performance of the material can be realized; this is of great significance for the optimization of the material properties. (Figure presented.).