High energy density induced by DA@NBT powders in PVDF flexible and transparent composite films

Energy storage of polymer-ceramic composite films is urgently demanded in modern electric power supply and renewable energy system. Herein, a series of flexible composite films are fabricated by combining Na0.5Bi0.5TiO3@dopamine (NBT@DA) as filler and poly(vinylidene fluoride) (PVDF) as matrix via a solution casting method. The sample with 1 vol% NBT@DA/PVDF composite film exhibits the highest breakdown strength (380 kV/mm), and thus a high energy density of 9.16 J/cm(3) is achieved in the composition, which is 1.5 times higher than that of pure PVDF. The improved breakdown strength is attributed to the reduced mobility of polymer chains induced by the NBT@DA powders. In addition, the outstanding transmittance and flexibility make the composite films as a promising candidate for future flexible portable energy devices.