Poly(methyl methacrylate)-based ferroelectric/dielectric laminated films with enhanced energy storage performances

In order to improve the energy storage density of poly(methyl methacrylate)-based (PMMA) flexible film dielectric capacitors, the ferroelectric phase poly(vinylidene fluoride) (PVDF) is introduced. Firstly, a blended structured PVDF doped PMMA composites is prepared and the polarization strength is apparently enhanced. However, the breakdown strength has been sacrificed due to the large amounts of defects caused by the different phases blending. To eliminate the influence of the blended structure on the breakdown strength, we designed a double-layer structure prepared by hot pressing at the temperature near the melting point of the polymers. The interfacial bonding of the composite films is controlled well to achieve high breakdown. Finally, a discharge energy density of 14.13 J/cm3 is obtained at a high electric field of 700 kV/mm in the double-layer structured PMMA and PVDF composite films, which is one times larger than that of pure PMMA films and 6 times larger than that of commercially available biaxially oriented polypropylene (BOPP) capacitors. In addition, the energy efficiency maintains up to 75% at 700 kV/mm. This work provides an effective approach for improving the energy storage density performance of polymer-based capacitors.Graphical abstractA double-layer structure was prepared by hot pressing at the temperature near the melting point of the polymers. In the composite, the discharge efficiency maintains around 75% at high-field electric and the energy storage density can reach 14.13 J/cm3, which is much larger than others composite.