High performance capacitors via aligned TiO2 nanowire array

Capacitors generally suffer from low energy density, which seriously limits their applications in energy storage devices. In this letter, TiO2 nanowire arrays were synthesized by a hydrothermal method and the morphologies were tuned by modulating the concentration of the Ti source. High energy density was realized after incorporating TiO2 nanowire arrays into a polyvinylidene fluoride matrix. The alignment of TiO2 nanowires with the direction of the applied electric field played an important role in achieving high breakdown strength and energy density, i.e., 380 kV/mm and 23.21 J/cm3, respectively. The findings provide a route to increase the energy density of polymer capacitors.