Enhancing energy storage density of poly(arylene ether nitrile) via incorporating modified barium titanate nanorods and hot-stretching

Dielectric energy storage materials that are extensively employed in capacitors and other electronic devices have attracted increasing attentions amid the rapid progress of electronic technology. However, the commercialized polymeric and ceramic dielectric materials characterized by low energy storage density face numerous limitations in practical applications. In this study, we report the simultaneous enhancement of dielectric properties of poly(arylene ether nitrile) (PEN) through the incorporating of sulfonated PEN (SPEN) modified barium titanate nanorods (BTNR) (SPEN@BTNR) and hot-stretching. BTNR is synthesized using a two-step hydrothermal method, aminated with KH550, and then reacted with SPEN to form the cladding-modified SPEN@BTNR. Due to the intrinsic high permittivity of barium titanate (BT) and enhanced compatibility between SPEN@BTNR and PEN stemming from the cladding of SPEN, the dielectric constant and breakdown strength of SPEN@BTNR/PEN composite are as high as 14.0 at 10³ Hz and 198.1 kV/mm at the doping amount of 15 wt.%, respectively. As a result, the energy storage density of SPEN@BTNR/PEN is increased to 2.43 J/cm³, compared with that of 0.82 J/cm³ for PEN. In addition, derived from the rearrangement of SPEN@BTNR and orientation of PEN after hot-stretching, the dielectric constant and breakdown strength of SPEN@BTNR/PEN with 15 wt.% fillers are further enhanced to 17.1 and 204.8 kV/mm, respectively, resulting in an energy storage density of 3.36 J/cm³. The boosting of energy storage density up to 310% provides a new idea for improving the performances of dielectric energy storage materials.