Largely enhanced high‐temperature energy storage performance of P(VDF‐HFP) dielectric films via calcium niobate nanosheets.

The capacitive energy‐storage capacity of most emerging devices rapidly diminishes with increasing temperature, making high‐temperature dielectrics particularly desirable in modern electronic systems. In this work, calcium niobate (Ca2Nb3O10, CNO) nanosheets have been added into poly(vinylidene fluoride‐hexafluoropropylene) (P(VDF‐HFP), PVHP), forming PVHP/CNO nanocomposites with exceptional temperature stability and ultrahigh energy storage density. Especially, at 80°C and 450 MV/m, the PVHP/0.3 wt%CNO nanocomposite shows an excellent Wrec of 10.81 J/cm3 which is higher than previous PVDF‐based composite films at high temperatures. Because of the high dielectric permittivity of CNO nanosheets and the way that the parallel organization of the nanosheets blocks the course of electrical trees, nanocomposites exhibit greater dielectric constants and breakdown field strengths simultaneously. These findings, will be helpful in the development of flexible, high‐energy‐density capacitors that have stable performance at high temperatures. Highlights: A record‐high high‐temperature Wrec is obtained.Excellent temperature stability from 25 to 80°C is achieved.The incorporation of Ca2Nb3O10 nanosheets significantly enhances Eb. [ABSTRACT FROM AUTHOR]