High-performance capacitors based on NaNbO3 nanowires/poly(vinylidene fluoride) nanocomposites

Abstract

Electrostatic capacitors with high power density have been demonstrated as efficient power sources in modern electrical and electronic devices. Nevertheless, the low energy density restricted the applications of electrostatic capacitors in the ever-developing electronic world. To improve energy density, herein, one-dimensional (1D) NaNbO₃ (NN) nanowires with a high-aspect-ratio are prepared by a simple hydrothermal method and introduced into a poly(vinylidene fluoride) (PVDF) matrix. The NN@PDA nanowires/PVDF nanocomposite films show a high discharge energy density of 12.26 J cm⁻³ at 410 MV m⁻¹, which is about 107% higher than that of pristine PVDF (5.87 J cm⁻³ at 350 MV m⁻¹) and 510% higher than that of the best commercial biaxially-oriented-polypropylenes (BOPP) (2 J cm⁻³ at 640 MV m⁻¹). Moreover, the composite films show a superior power density of 2.01 MW cm⁻³ and ultra-fast discharge speed of 146 ns. As verified by finite element simulations, 1D NN nanowires incorporation into the polymer matrix could significantly improve the local electric distribution and electric current density distribution in the nanocomposites. Ultimately, it is anticipated that this work will open a new design paradigm to boost the performance of polymer nanocomposites for compact and flexible electrical energy storage applications.