Bilayer PI/BaTiO3-P(VDF-TrFE-CFE) composites with high discharge energy density

Ferroelectric polymer P(VDF-TrFE-CFE) is widely employed as energy storage materials of dielectric capacitors, but the discharge energy density of P(VDF-TrFE-CFE) is limited by the lower breakdown strength, which restricts the further development. The paper proposes a solution by preparing P(VDF-TrFE-CFE) composites based on bilayer structure and nanoparticles. Polyimide (PI) with high breakdown strength is used as the bottom layer, and the BaTiO3/Ferroelectric polymer composites BT-P(VDF-TrFE-CFE) with high dielectric constant is used as the top layer, the bilayer composite films PI/BTP(VDF-TrFE-CFE) doped with different content of BaTiO3 (1 vol.%, 3 vol.%, 5 vol.%) were prepared via coating, heat treatment and quenching. The microstructure and energy storage performance of bilayer films were analyzed, the results show that the discharge energy density of composite film doping with 3 vol.% of BaTiO3 can be up to 9.8 J/cm3 at 440 kV/mm, which is higher than pure P(VDF-TrFE-CFE) film (7.2 J/cm3). The energy storage efficiency of composite film is 46% at 440 kV/mm, slightly lower than pure P(VDF-TrFE-CFE) film (49% at 337 kV/mm).