Ultra-low loadings of gold nanoparticles significantly boost capacitive energy storage of multilayer polymer composites

Abstract

Polymer dielectrics have been extensively studied for their high power density and fast charge–discharge rate. It is crucial to balance their dielectric constant and breakdown strength to achieve high energy storage density. In this work, a multilayer composite film consisting of ferroelectric polymer P(VDF–HFP) and linear polymer PMMA layers is designed. Meanwhile, two nanolayers of gold nanoparticles are sputtered at the P(VDF–HFP)/PMMA interface. The experimental results demonstrate that the introduction of gold nanoparticles synergistically enhances the dielectric and breakdown properties. In particular, the Coulomb blockade effect of ultra-small gold nanoparticles significantly boosts the breakdown properties. Compared to the multilayer film without gold sputtering, the film sputtered for 4 min shows a 34% increase in breakdown strength from 463.38 kV mm⁻¹ to 620.84 kV mm⁻¹ and a 202% increase in energy density from 4.58 J cm⁻³ to 13.82 J cm⁻³. This work provides an efficient strategy to design high-energy-density dielectrics for advanced pulsed power capacitor applications.