High energy density of BaTiO3@TiO2 nanosheet/polymer composites via ping-pong-like electron area scattering and interface engineering

Dielectric substances exhibit great potential for high-power capacitors due to their high stability and fast charge-discharge; however, a long-term challenge is to enhance energy density. Here, we propose a poly(vinylidene fluoride) (PVDF) composite utilizing BaTiO3 nanoparticle@TiO2 nanosheet (BT@TO ns) 2D nanohybrids as fillers, aiming at combining the interfacial strategy of using a core-shell filler and the electron scattering of a 2D filler to improve the energy density. With 4 wt% filler, the composite possesses the largest breakdown strength (E-b) of 561.2 MV m(-1), which is significantly enhanced from the 407.6 MV m(-1) of PVDF, and permittivity of 12.6 at 1 kHz, which is a 23% increase from that of PVDF. A superhigh energy density of 21.3 J cm(-3) with an efficiency of 61% is obtained at 550 MV m(-1). The 2D BT@TO ns-filled composite exhibits a higher energy density than composites filled with core-shell 1D BT@TO nws or non-core-shell 0D BT, 1D TO, or 2D TO particles. The E-b and energy density improvements are attributed to the buffer layer-based interface engineering and enhanced area scattering of electrons caused by the 2D hybrids, an effect similar to that of a ping-pong paddle to scatter electric field-induced charge migrations in composites. Thus, an effective hybrid strategy is presented for achieving high-performance polymer composites that can be used in energy storage devices.

Automated summary

Dielectric substances have the potential to be used in high-power capacitors due to their stability and fast charging ability. However, enhancing energy density has been a long-term challenge. In this study, a poly(vinylidene fluoride) composite filled with BaTiO3 nanoparticle@TiO2 nanosheet 2D hybrids was proposed to improve energy density. Experimental results showed that the composite had higher breakdown strength, permittivity, and energy density compared to composites filled with other types of particles. The improvements were attributed to the interface engineering and electron scattering effects of the 2D hybrids. Overall, an effective hybrid strategy was presented for high-performance polymer composites in energy storage devices.