Excellent high-temperature dielectric energy storage of flexible all-organic polyetherimide/poly(arylene ether urea) polymer blend films

Current commercial dielectric polymers can scarcely meet the increasing demand for advanced capacitors under harsh thermal conditions up to 150 °C due to the severely degraded efficiency at high electric field and high temperature. Here, we design and prepare all-organic polyetherimide/poly(arylene ether urea) polymer blend films which exhibit a record-high discharged energy density of ∼4.84 J/cm3 with an efficiency higher than 90% at 150 °C among the reported free-standing all-organic polymer-based dielectrics. Moreover, the capacitive energy storage performance shows an excellent temperature stability from room temperature to 150 °C, and a great long-term reliability over 20,000 cycles is achieved under working conditions of 200 MV/m and 150 °C in hybrid vehicles. These excellent dielectric energy storage performances benefit from the introduction of molecular trapping centers which notably reduce the high-temperature conduction loss. Our research provides a convenient and effective method to develop high-temperature polymer dielectrics.