Enhancing high-temperature energy storage performance of poly(arylene ether nitrile) hybrids synergistically via phthalonitrile modified boron nitride and carbon nanotube

Polymer dielectrics with high energy density (ED) and excellent thermal resistance (TR) have attracted increasing attention with miniaturization and integration of electronic devices. However, most polymers are not adequate to meet these requirements due to their organic skeleton and low dielectric constant. Herein, we propose to fabricate ternary hybrid materials with improved ED and TR via self crosslinking of phthalonitriles terminated polyaryl ether nitrile (PEN), phthalonitriles modified boron nitride (BN-2CN), and carbon nanotube (CNT-2CN). FTIR, DSC, TGA, XPS, DMA, AFM, and SEM measurements confirm the fabrication of the CPEN-BN-CNT hybrids. With the addition of BN-2CN and CNT-2CN, the dielectric constant and breakdown strength of these hybrids are synergistically enhanced; as a result, the discharged ED of CPEN-BN8-CNT1 is increased to 2.48 J/cc, with an increment of 188% comparing with that of PEN. Accounting for the crosslinking of CPEN-BN-CNT hybrids, their TR is obviously promoted with their T_g and T_5% higher than 420 and 520 °C. Thermal decomposition kinetics calculations show that CPEN-BN8-CNT1 can be continuously used at 300 °C for 7.5 × 10⁴ years and 350 °C for 12.6 years. Therefore, the fabricated CPEN-BN-CNT hybrids demonstrate leaps in ED and TR simultaneously, which is an important reference for the preparation of advanced polymeric dielectrics.