Dielectric and energy storage properties of PVDF films with large area prepared by solution tape casting process

A pilot-scale poly(vinylidene fluoride) (PVDF) film with a thickness of 2-20 μm, a width of 15 cm and a length of above 250 m was fabricated by using solution tape casting process. The crystallinity, dielectric and energy storage properties of the PVDF film were studied. The results displayed that there were predominant β phase in the PVDF film prepared at 60 °C, and coexistence of α and β phases at 80 °C. The PVDF film fabricated at 80 °C exhibited a dielectric constant of 8.7 and a dielectric loss of 3.8% at 1 kHz and room temperature. The discharged energy density calculated from D-E hysteresis loop reached to 10.1 J/cm3with charge-discharge efficiency of 37.9% at 550 MV/m.