Synthesis and Characterization of PVDF CaCu3Ti4O12 Nanocomposite for High Energy Density Capacitors

Abstract

Polymer ceramic nanocompositesare highly in demand due to its prospective applications in electrical and electronics engineering e.g. embedded electronics, varistors, sensors, and high energy density capacitors. Ceramic materials which are usually used as a filler in the polymer matrix such as lead zirconate titanate (PbZrTiO3 ), lead titanate (PbTiO3), barium titanate (BaTiO3), barium strontium titanate ( BaxSr1-xTiO3), etc.possesses a high dielectric constant. But, the dielectric strength of these ceramics is low due to their brittle nature. On the other side, polymers such as polyvinylidene fluoride (PVDF), polyvinyledenedifluoride trifluoroethylene (PVDF-TrFE), biaxially oriented polypropylene (BOPP) etc shows high dielectric strengthandlow dielectric constants (i.e. lt 10). So, incorporationof the ceramic materials inthe polymer matrix could become a promising material for high energy density capacitor and other applications. Among all the polymers, polyvinylidene fluoride (PVDF) is flexible in nature and, has high dielectric breakdown strength but low intrinsic permittivity. Besides this, it is very versatile in nature as it exist in different crystalline phase viz.and#945;, and#946; and and#947;-phases having different dielectric and polarization behavior.The evolution of these phases are controlled by different ways of processing e.g. quenching, annealing, stretching etc. The and#946; and and#947;-phases are polar in nature, but the tangent loss of and#947;-phase is found to be less as compared to and#946;-phase. The and#947;-phase of PVDF is found to be most suitable for energystorage applications. The dielectric and energy storage behavior of polymer ceramic nanocomposite based on PVDF have been widely investigated. Among all dielectric ceramics, calcium copper titanate (CaCu3Ti4O12) ceramic shows colossal dielectric constant (and#949; ~ 104 -105) which is constant over a broad frequency (102 Hz -106 Hz) and temperature range (100 K -600 K).