Three series of poly (vinylidene fluoride-chlorotrifluoroethylene)/barium titanate (BT) nanocomposites with varied compositions were fabricated via solution cast process followed by thermally treated in different ways. Quenching the composite samples at lower temperature could effectively enhance their dielectric constant, breakdown strength as well as the energy density. The highest energy density (13.6 J/cm3) is observed in the sample quenched from 200 degrees C to 94 degrees C with 5 vol% BT, which is much higher than nanocomposites reported in the current literature. The addition of ceramic particles leads to the improvement of dielectric permittivity and energy density measured under the same electric field. However, the dielectric breakdown strength and the energy density measured at breakdown strength of the resultant composites are reduced as a function of BT content. The fixed maximum electric displacement and reduction of saturation electric field suggest that the addition of ceramic particles with high dielectric constant may help increase the energy density of composites under low electric field but not for high electric field. POLYM. ENG. SCI., 2013. (c) 2012 Society of Plastics Engineers.