Layered porous Na0.5Bi0.5TiO3-0.06BaTiO3 for enhanced pyroelectric thermal energy harvesting

Abstract

Layered Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT) ceramics of dense-porous-dense structure along the thickness are fabricated. The porous layer is sandwiched between the top and bottom dense layer, nullifying the electrode material's seepage into pores. Thus, porous pyroelectric material reduces the dielectric breakdown during poling and increases the repeatability of the poling process. The burnt-out polymer technique creates 10.7 %, 14.23 %, 21.3 % and 28 % porosity. The dielectric constant in layered porous structure decreased from 785 to 221 as the porosity increased from 5.4 % (pure NBT-6BT) to 28 % (layered NBT-6BT-12) at room temperature (poled condition). The introduction of porosity showed an increment of 124 % in the modified pyroelectric energy harvesting figure of merit Fe* for NBT-6BT-12 at 80 °C. The real-time thermal energy harvesting obtained by heating and cooling the pyroelectric material demonstrated equivalent voltage for NBT-6BT-12 layered porous structure. The layered porous structure can be a viable alternative for enhanced voltage sensitivity and energy harvesting.