Large Electrocaloric Effect in Ferroelectric Polymers Near Room Temperature

Abstract

Applying an electrical field to a polar polymer may induce a large change in the dipolar ordering, and if the associated entropy changes are large, they can be explored in cooling applications. With the use of the Maxwell relation between the pyroelectric coefficient and the electrocaloric effect (ECE), it was determined that a large ECE can be realized in the ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer at temperatures above the ferroelectric-paraelectric transition (above 70 degrees C), where an isothermal entropy change of more than 55 joules per kilogram per kelvin degree and adiabatic temperature change of more than 12 degrees C were observed. We further showed that a similar level of ECE near room temperature can be achieved by working with the relaxor ferroelectric polymer of P(VDF-TrFE-chlorofluoroethylene).

Multicaloric effect in ferroelectric PbTiO3from first principles

“…Contrary to the old belief that such effects, while common, are miniscule, a large variety of giant caloric effects has been recently discovered in some ferroic materials [1][2][3][4][5][6][7][8][9][10] . These discoveries have opened the door to the use of these giant effects in an efficient and environmentally friendly solid-state refrigeration technology.…”

“…Moreover, given a relative abundance of extrinsic multiferroics among ferroics with multiple order parameters, such prediction may open an unusual route to solid state refrigeration advancement. Recent discoveries of giant caloric effects in some ferroic materials [1][2][3][4][5][6][7][8][9][10] have opened the door to the use of solidstate materials as an alternative to gases for conventional and cryogenic refrigeration 11 . The wide class of ferroics includes such diverse materials as ferromagnets and magnetic materials, ferroelectrics, ferroelastics and multiferroics.…”

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

“…Th e tuning parameter for the caloric eff ect (external fi eld) can be any generalized thermodynamic force, provided that the change in the conjugated generalized thermodynamic displacement is large enough. Hence, giant caloric eff ects have already been reported for magnetic fi eld (magnetocaloric eff ect) 1 -3 , electric fi eld (electrocaloric eff ect) 4,5 , uniaxial stress (elastocaloric eff ect) 6 and hydrostatic pressure (barocaloric eff ect) 7,8 .…”

Electrocaloric and elastocaloric effects in soft materials

“…It was shown recently that a giant ECE can be observed in inorganic perovskite ferroelectric thin films [1][2][3][4]6,9,10] as well as in organic, P(VDF-TrFE)-based ferroelectric copolymers [1,11,12]. First proof of concept cooling devices were produced from these solid-state materials, but with rather low power density due to the relatively large EC inactive regenerator mass [13,14].…”