Engineering Poly(phthalazinone ether sulfone) Dielectric Films for Stable High-Temperature Capacitive Energy Storage

Poly(aryl ether) (PAE) dielectrics have captured widespread interest in the domain of film capacitors primarily due to their exceptional high-temperature endurance, advantageous film-forming capabilities, and superior mechanical attributes. However, the conventional PAEs had a complicated film-forming process and low discharge energy density. In order to solve this problem, a poly(phthalazinone ether sulfone) (PPES) with phthalazinone structures is synthesized. Compared to the commercial polysulfone, the PPES exhibits significantly higher discharge energy density (U-e) and breakdown strength both at room temperature and elevated temperature. In particular, the U-e value of PPES (3.66 J/cm(3)) at 150 degrees C and 500 MV/m is even superior to that of commercially available bi-oriented polypropylene dielectric films, which are only 2.71 J/cm(3) at room temperature and 450 MV/m. This investigation has demonstrated that the PPES films with phthalazinone structures are highly promising for energy storage under harsh conditions.