Linear and ferroelectric effects of BaTiO3 particle size on the energy storage performance of composite films with different polymer matrices

Abstract The size of ceramic fillers is an important parameter influencing the energy storage performance of composite materials. Herein, composite films containing linear poly (methyl methacrylate) (PMMA) and ferroelectric polyvinylidene fluoride (PVDF) polymer matrices and BaTiO3 (BT) particles with different sizes were fabricated, and the dependences of their dielectric and energy storage properties on BT particle size were investigated systematically. The observed particle size effects on the PMMA/BT and PVDF/BT characteristics were almost identical. In particular, the dielectric permittivities of the composites gradually decreased while their breakdown electric fields (Eb) increased with an increase in BT particle size. Moreover, the composite films with small BT particles exhibited high discharged energy densities (Udischarged) at relatively low electric fields. The Udischarged of the PMMA/BT-60 nm sample was 5.68 J/cm3, which was 1.24 times higher than that of the PMMA/BT-500 nm sample at an electric field of 450 MV/m. Meanwhile, the Udischarged of PVDF/BT-60 nm was 10.06 J/cm3, which was 1.27 times greater than the Udischarged of PVDF/BT-500 nm at 350 MV/m. However, under high electric fields, the composite films with large BT particles produced higher Udischarged values. The maximum Udischarged magnitudes of the PMMA/BT-500 nm and PVDF/BT-500 nm samples were equal to 9.53 J/cm3 at 650 MV/m and 18.12 J/cm3 at 525 MV/m, respectively. Furthermore, the composite films filled with 500 nm BT particles demonstrated high cycling stability and fatigue endurance. The results of numerical simulations conducted to complement the experimental data revealed that the composite films with large BT particles possessed higher breakdown strengths.