Study on the Effect of Inorganic Fiber on the Energy Storage Characteristics of Sandwich Composite Films

Polymer-based composite dielectrics are expected to be widely used as key materials for thin film capacitors in fields such as pulsed power supplies and high-power energy storage systems due to their excellent breakdown performance and excellent flexibility. This work uses PVDF polymers as a matrix and introduces PMMA to reduce dielectric loss. Inorganic fibers with different structures were designed and filled into the intermediate layer of the sandwich structure, with polymers selected as outer layers on both sides to maintain flexibility. It was found that the addition of Ag particles can effectively improve the polarization strength of the composite film, but the breakdown characteristics also deteriorate. However, the addition of the Al2O3 shell layer can effectively alleviate the problem of breakdown degradation and reduce ferroelectric losses. Finally, ABA Film has the best energy storage characteristics, with a discharge energy storage density of 5.98 J/cm2, and a charge–discharge efficiency of not less than 65.4%.