Greatly enhanced energy density in polymer nanocomposites coated with high-k perovskite nanosheets

Polymer dielectric materials with high energy storage density are vital component in advanced electronic devices. However, the increase of conduction loss at relatively high electric field will lead to film failure and hinder the exploration of high energy density in the dielectric polymer. Herein, a general strategy is proposed to effectively enhance the breakdown strength and energy density by coating wide bandgap Ca2Nb3O10 nanosheets on the surface of the polyvinylidene fluoride film using Langmuir-Blodgett and spray coating technologies. The coating layers of Ca2Nb3O10 nanosheets exhibit high insulation feature, and therefore, suppress the leakage current density of the nanocomposite film, resulting in remarkably enhanced breakdown strength of 710 MV/m and discharged energy density of 25.1 J/cm3, with a satisfactory charge–discharge efficiency of 78%. Our work may provide a scalable, and yet effective route to tailor the energy storage density of polyvinylidene fluoride-based polymers.