Tuning interfacial relaxations in P(VDF-HFP) with Al2O3@ZrO2 core-shell nanofillers for enhanced dielectric and energy storage performance

High energy density is a desirable index for advanced energy storage materials. Here, core-shell structured nanoparticles Al2O3@ZrO2 ([email protected]) are synthesized to fabricate P(VDF-HFP)/[email protected] nanocomposite films. Experimental and simulation results confirm that [email protected] nanoparticles are effective in suppressing the local electric field distortion of nanocomposites, as well as intensifying the interfacial polarization without affecting the intrinsic orientational polarization. The activation energy of the interfacial relaxation in crystalline/amorphous region is increased from 0.96 eV of the neat P(VDF-HFP) to 1.25 eV of P(VDF-HFP)/5 vol%[email protected] nanocomposite. Meanwhile, a new dielectric relaxation with energy of ∼1.08 eV related to nanoparticles/amorphous phase of P(VDF-HFP) is induced. The modulated interfaces present substantial capability in inhibiting charge motion, which contributes to an improved electrical property and energy density of the nanocomposites. Specifically, a ∼200% enhancement in discharged energy density is achieved in the P(VDF-HFP)/5 vol%[email protected] nanocomposite, demonstrating a promising dielectric material choice for energy storage capacitor applications.