Cellulose/BaTiO3 nanofiber dielectric films with enhanced energy density by interface modification with poly(dopamine)

Flexible electrostatic capacitors have many potential applications in modern electric power systems. In this study, flexible cellulose-based dielectric films were prepared by compositing regenerated cellulose (RC) and one-dimensional BaTiO3 nanofiber (BTNF) via a simple and environmentally friendly process. To improve compatibility and distributional homogeneity of the fillers/matrix, BTNF was surface modified by dopamine to prepare the poly(dopamine) modified BTNF ([email protected]). The obtained RC/[email protected] composite films ([email protected]) possessed higher dielectric constant and breakdown strength than those of the RC and RC/BTNF composite films. In particular, RC/[email protected] composite films with 2 vol% [email protected] ([email protected]) exhibited a high discharged energy density of 17.1 J/cm3 at 520 MV/m, which exceeded 40 % compared with that of RC-2BTNF at 460 MV/m. Meanwhile, [email protected] could continuously work for more than 10,000 times with a high efficiency of 91 %. Furthermore, the composite films could maintain good dielectric properties for a long time when stored in vacuum condition (under 0.3 atm). Therefore, these flexible cellulose-based dielectric materials are promising in the field of novel high-performance film dielectric capacitors.