Excellent energy storage performance in polymer composites with insulating and polarized two-dimensional fillers

Flexible dielectric materials have given rise to extensive attention in power electronics and other fields because of their outstanding superiorities such as high-power density. However, how to effectively heighten the energy storage density of the dielectric is a long-term challenge. The single fillers introduced tends to focus on enhancing the insulating or polarized properties of the composite, which limits further improvements in energy storage density. In this paper, through the co-doped of insulating boron nitride (BNNS) and polarized titanium dioxide (TiO2) two-dimensional nanosheets, the polarization strength is enhanced, and the breakdown strength can maintain at a high level, then an excellent energy storage density of 20.08J/cm3 and charge–discharge efficiency of 73 % are obtained. Meanwhile, the co-doped composite has great stability and an ultrahigh power density close to 5 times of BOPP. This study offers a guidance for the reasonable design of P(VDF-TrFE-CFE) polymer composite with excellent electric storage properties.