Ultrahigh efficiency and enhanced discharge energy density at low loading of nanofiller in trilayered polyvinylidene fluoride-Ba0.8Sr0.2TiO3 nanocomposites

Abstract

Poly(vinylidene)fluoride-Ba0.8Sr0.2TiO3 (PVDF-BST) trilayered nanocomposites (with different vol% loading of BST nanoparticles, i.e. 0.75%, 1.50%, 2.25% and 3.00%) has been processed by the tape casting technique. The upper and lower layers of the nanocomposites are casted in the same direction, whereas the middle layer is casted in the opposite direction. The trilayered PVDF-BST nanocomposite consisting of 3.00 vol% of BST nanoparticles exhibited high dielectric permittivity (~25), low tangent loss (~0.03) and moderately high breakdown strength (BDS ~282 MV/m). Moreover, it also possesses a high discharge energy density (~7.8 J/cc at 1400 kV/cm) and efficiency (~93%). A mechanism for the excellent energy storage behavior and dielectric properties has been proposed. Where, moderately high BDS and low tangent loss are associated with the spatial distribution of the local electric field at interlayer interfaces of PVDF-BST trilayered nanocomposites, which restricts the conduction of charge carriers at high electric field. The ultrahigh efficiency and enhanced discharge energy density is attributed to the formation of interfacial dipoles at various interfaces such as interlayer, intralayer (PVDF/PVDF), and PVDF/BST interfaces. These investigations would be adopted as a futuristic strategy for developing excellently efficient polymer-ceramic nanocomposites for the high energy density capacitors used in pulsed power applications. Highlights: PVDF-BST trilayered nanocomposites exhibit high ε′ ~25 and low tanδ ~0.03. Nanocomposite shows ultra-high energy efficiency ~93% and enhanced UD ~ 7.8 J/cc. Mechanism for the excellent energy storage and dielectric properties Relies on the interfacial dipoles and distribution of the local electric field.