Crosslinked poly(arylene ether ketone)s with lateral methylsulfone groups for capacitive energy storage

Polymer dielectrics are vital materials for thin film capacitors, and their performance directly determines the energy storage density and reliability of capacitors. This work focuses on the synthesis of poly(arylene ether ketone)s polymer dielectrics utilizing monomer S-BPA, which features lateral methylsulfone groups with a large dipole moment. Among the synthesized polymers, ASPEK_20% stands out with a dielectric constant of 4.2 and an extremely low dielectric loss of about 0.003. Additionally, it exhibits a remarkable discharged energy density of up to 11.10 J cm⁻³ at an electric field strength of 760 MV m⁻¹, along with a discharge–charge efficiency of 87.5 %. The outstanding energy storage capabilities of this polymer materials can be primarily attributed to two factors: the first is the high dielectric constant caused by the dipole of the lateral methylsulfone groups with strong polarity; furthermore, its high breakdown field strength is enhanced by cross-linking of propenyl group, suppressing the movement of the lateral methylsulfone dipole. Our work may provide a comprehensive and practical strategy to prepare high performance polymer dielectrics for thin film capacitors.