NaNbO3 two-dimensional platelets induced highly energy storage density in trilayered architecture composites

Polymer-based dielectric materials with high power density, high energy density, and broad operating temperature range are critical to the development of cost-efficient and lightweight capacitors for modern high-power electrical systems. Here, NaNbO3 (NN)/polymer composites, especially two-dimensional (2D) NN platelets, were used to create new composite films for energy storage applications for the first time. The trilayered architecture composites comprised of two outer layers of 2D NN platelets dispersed in a poly(vinylidene fluoride) (PVDF) matrix to provide high dielectric constant and a middle layer of pristine PVDF to offer high breakdown strength. The breakdown strength and energy density of the trilayered architecture composite films were improved significantly via tailoring the contents of the 2D NN platelets. The composite films with an optimized filler content illustrate a high discharge energy density of 13.5 J cm−3 at 400 MV m−1, far more than the best commercial biaxially- oriented polypropylenes. Moreover, the composite films show a superior power density of 2.68 MW cm−3 and ultra-fast discharge speed of 0.127 μs. Finite element simulation further revealed the breakdown strength and energy density of the composite films were much enhanced compared to the corresponding single layer composite films. Therefore, the new trilayered architecture composite films can be applied as an alternative promising high-performance electrostatic capacitor material.