Suppressing dipole-dipole coupling enable high-capacitance relaxor dielectrics with highly polar fluorinated aromatic polythiourea in all-organic capacitor prototype

Balancing the contradict factors of high-dielectric-constant ( K) and high-breakdown-strength ( E b ) becomes a major obstacle that hinders the development of high-power-density ( U e ) dielectric capacitors. Herein, we successfully synthesize a high- E b and medium- K dielectrics of fluorinated aromatic polythiourea (F-ArPTU) via microwave radiation polymerization, and develop a high- U e relaxor dielectrics comprising of a high- K poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroethylene) (RFPs) and a high- E b F-ArPTU. Due to crystallization-induced separation, ultrahigh-insulation F-ArPTU can be segregated to the periphery of RFPs crystals, which is beneficial for suppressing dipole-dipole coupling to form smaller relaxor crystals in the composites compared with pristine RFPs. The confined effect of RFPs crystals results in not only balancing the contradict factors of high- K and high- E b , but also improving the capability of dipole switchablity, thereby achieving high- U e , and low loss in the composite system. For instance, the relaxor dielectrics RFPs with 20 wt% F-ArPTU possesses a relatively high- U e of 10.2 J cm −3 at the field of 320 MV m −1 , which is higher than that of biaxially oriented polypropylene (BOPP) and other all-organic dielectric polymers. As an all-organic capacitor prototype, the 20F-ArPTU/RFPs capacitor with a dimension of 5 × 5 cm 2 enable five times higher efficacy on power supply for electronic devices than the benchmark BOPP capacitors.