Remarkably boosting capacitive energy storage of layer-structured nanocomposites via the incorporation of Au quantum...

Polymer dielectrics are widely employed in pulsed energy storage and conversion systems due to their ultrahigh power density, fast discharge speed, and reliability. However, their low discharge energy densities pose a significant limitation for application in miniaturized and integrated devices. Here, a significantly enhanced energy storage property is achieved via incorporating Au quantum dots (QDs) into a sandwich-structured nanocomposite, where the PMMA/P(VDF-HFP) (A/F) blended polymer serves as middle layer and the P(VDF-HFP) acts as outer layer. Benefiting from the micro-capacitor and Coulomb blockade effects induced by the Au QDs, the resulting nanocomposite simultaneously achieves enhanced dielectric constant of 10.34 at 10 kHz and breakdown strength of 577.3 MV m^-1. Subsequently, a significantly enhanced discharge energy density of 16.07 J cm^-3 is further acquired, which is approximately 177.1 % that of the nanocomposite without Au QDs. This work proposes a novel structure design combining Au quantum dots with a sandwich-structured composites, which also provides a feasible paradigm for optimizing the energy storage performance of polymer dielectrics.