Enhanced energy density of polymer nanocomposites at a low electric field through aligned BaTiO3 nanowires

Abstract

In practical application, new dielectric capacitors with greater energy density at lower operating voltage will be promising candidates for high-performance electrical devices. Theoretically, it is possible to achieve large electric polarization at a low electric field via embedding aligned ferroelectric nanowires in a polymer matrix, which could release high energy density. However, in terms of practice, the design of nanocomposites with aligned nanowires poses a great technical challenge. Here, a new physical-assisted casting method was developed to tune the orientation of elongated BaTiO₃ nanowires in a P(VDF-CTFE) matrix. In the Z-aligned nanocomposites, a large (D_max − P_r) value of 9.93 μC cm⁻² can be induced at a low electric field of 2400 kV cm⁻¹ by aligning 3 vol% ferroelectric BaTiO₃ nanowires in the poling direction. Compared with X–Y-aligned nanocomposites even at a high electric field of 3400 kV cm⁻¹, the Z-aligned nanocomposites could exhibit simultaneously an enhanced energy density of 10.8 J cm⁻³ and a discharge efficiency of 61.4% at 2400 kV cm⁻¹. To the best of our knowledge, among ferroelectric nanocomposites, this is the highest energy density ever obtained at such a low electric field. This work is of critical significance in making dielectric nanocomposites viable for energy storage devices in current electrical and electronic applications.