Enhanced energy storage performance in polypropylene-acrylic acid grafted polypropylene-ZrO<sub>2</sub> ternary nanocomposites
Wenfeng Liu, Hongbo Liu, Lu Cheng, Shengtao Li
Abstract
Abstract To improve the energy storage density while maintaining low dielectric loss is crucial for the miniaturization of capacitors. In the present study, we proposed a ternary nanocomposite system comprised of polypropylene (PP), acrylic acid grafted PP (PP-g-AA), and nano-ZrO 2 . The PP-g-AA was firstly prepared by a free radical grafting with the proportion fixed to 50 wt%, and the content of nano-ZrO 2 ranged from 0.5 wt% to 5 wt% to tailor the ternary composite. The transmission electron microscope observation showed that PP-g-AA could significantly benefit the dispersion of nanoparticles and the differential scanning calorimetry results indicated the superior compatibility of the ternary nanocomposites. Accordingly, with the optimum nano-ZrO 2 content of 0.5 wt%, the ternary nanocomposites achieved the permittivity of 2.7 and DC breakdown strength of 456.2 kV mm −1 , resulting in the enhanced energy density of 2.77 J cm −3 which was 60% higher than neat PP, while the dielectric loss was kept lower than 0.003. Moreover, even at the temperature of 120 °C, the ternary nanocomposites maintained a high-performance energy storage density of 2.28 J cm −3 (with energy storage efficiency above 90%), which was 670% of the neat PP.