Enhancing the energy storage performance of PVDF films through optimized hot-pressing temperatures

Poly(vinylidene fluoride) (PVDF) polymers have garnered significant interest due to their dielectric tunability and applications in micro-electric high-power systems. However, the relationship between structure and energy storage performance is not yet fully illustrated, particularly regarding the fabrication process. Herein, the influence of hot-pressing temperature on the structural and electrical properties were systematically studied, and the optimal temperature was also determined. PVDF films after hot-pressing at 150 ℃ exhibited a high discharged energy density (ESD) of 19.24 J/cm³, coupled with a large breakdown strength (E_b) of 604.08 kV/mm and a high efficiency (η) of 68.99%. The primary contribution to the improved ESD originates from the enhanced crystallinity resulting from the formation of more α-phase and γ-phase structures. Concurrently, the decrease in defects can also promote the enhancement of breakdown strength. This work can provide valuable insights into the optimization of the fabrication process to achieve superior energy storage performance in PVDF films.