Excellent Energy Storage and Discharge Performances Realized in Polymer Nanocomposites by Introducing Core-Shell Antiferroelectric Fillers and Constructing Bilayer Interfaces

Polymer composites filled with one or two-dimensional ferroelectrics possess large discharged energy density (Ue), but deliver low efficiency (eta) by reason of their high remnant electric displacement (Dr), and require demanding process conditions. To solve these issues, we have proposed Pb,La(Zr,Sn,Ti)O3 (PLZST)@Al2O3 nanoparticles (NPs)/polyimide (PI)-PLZST@Al2O3 NPs/poly(vinylidene fluoride-hexafluoropropylene) P(VDF-HFP) bilayer nanocomposites. PLZST antiferroelectrics exhibit small Dr and high maximum electric displacement (Dmax), and the Al2O3 shell possesses near dielectric constant with P(VDF-HFP) and PI, which can improve the Dmax, increase the breakdown strength (Eb), and refine D -E loops, and simple preparation method of the NPs is beneficial for the industrial production. The bilayer structure combines advantages of PLZST@Al2O3 NPs/PI with slim D -E loops and small Dr, and PLZST@Al2O3/P(VDF-HFP) possessing high Dmax. Besides, large dielectric differences between adjacent layers inhibit electrical tree growth, thus further causing improved Eb, which is confirmed by electrical tree evolving simulations. Consequently, the bilayer nanocomposites display an ultrahigh Ue of 21.89 J/cm3, which surpasses those of currently reported polymer nanocomposites filled with NPs, and large eta of 78.2%. More encouragingly, it manifests ultrafast discharge time of 18.8 ns and ultrahigh power density of 28.3 MW/cm3, meaning its great application prospect in pulse power systems.