Improved energy density and charge-discharge efficiency in solution processed highly defined ferroelectric block copolymer-based dielectric nanocomposites

The development of light and flexible capacitive energy storage devices with high electrical energy densities is of crucial significance to respond to the ever-rising demands in advanced applications and electricity needs. Incorporation of high dielectric constant ceramic fillers inside the ferroelectric polymer matrix offers great potential to improve the energy density of dielectric materials. However, this approach often suffers from highly reduced breakdown strength caused by the large difference of the matrix and filler dielectric constants together with often poor dispersion of the ceramic additives inside the polymer. Here, we demonstrate a simple method for the preparation of improved polymer-based dielectric nanocomposites based on self-assembly of medium dielectric constant hafnium oxide nanorods using ferroelectric block copolymer. The prepared nanocomposites exhibit both improved discharged energy densities and charge-discharge efficiencies, whereas they preserve their function up to comparable electric fields as the pristine block copolymer. The enhancement of the properties is mostly ascribed to the formation of deeper charge traps due to nanorod induced crosslinking inside amorphous domains and the reduction of ferroelectric loss influenced by creation of an additional paraelectric phase in nanocomposites.