Clean Technology 2008
B. Chu, B. Neese, M. Lin, X. Zhou, Q. Chen, Q.M. Zhang
The Penn State University, US
dielectric, energy density, nanocomposite, polymer blends
Large enhancement in the electric energy density and electric displacement level were found in nanocomposites of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (PVDF-TrFE-CFE) relaxor ferroelectric polymer/ZrO2 nanoparticles. Through the interface effect the presence of the nanoparticles (with only 1.6 vol% of ZrO2 nanoparticles in the composite) raises the maximum electric displacement D from 0.085 C/m2 under 400 MV/m in the neat terpolymer to more than 0.11 C/m2 under 300 MV/m in the nanocomposites. Consequently, a high energy density of 10.5 J/cm3 can be achieved under a lower field (300 MV/m) in the nanocomposites compared with the neat terpolymer. Similarly, in PVDF terpolymer/ copolymer blends, the improvement of energy density was also observed. Addition of small amount of copolymer (less than 10wt% copolymer) into terpolymer could greatly improve the breakdown field of terpolymer, and at the same time the electric displacement of terpolymer was not reduced or even enhanced. Evidences show that the polymer-polymer interface may contribute to the field induced electric displacement. The highest energy density obtained in the terpolymer/copolymer blends is around 11.5J/cm3 under an electric field of 375MV/m.