Enhenced energy storage performance of polyetherimide by adding few amount of CNO nanosheets

The low dielectric constant of polymers restricts their usage in energy storage capacitors. Existed methods of adding traditional ceramic fillers to enhance dielectric constant of polymers inevitably sacrifice their machinability since large amount of fillers are required. In addressing this issue, this work prepared the polymer-based composites by selecting the calcium niobate (CNO) nanosheets with high dielectric constant as fillers, the polyetherimide (PEI) as polymer matrix. At a low loading level (1 wt%), the PEI/CNO composite present excellent energy performances due to their enhanced dielectric constant and suppressed dielectric loss. The strong interactions between the negative charged CNO surface and the positive charged O atoms in polymer chains endow the PEI/CNO composites with these excellent performances. Finally, the finite element analysis simulation and the density functional theory calculation were employed to confirm these results. This work provides a simple method in fabricating polymer-based dielectrics focused on the practical application, which might serve some new ideas in designing capacitive polymers.