Grain size and lattice compatibility enhanced figure-of-merit in Ba0.95Ca0.05Ce0.005ZrxTi0.995−xO3 material for pyroelectric energy conversion

Phase-transforming ferroelectric materials have attracted significant attention due to their potential for energy conversion from waste heat. Here, we explore the impact of grain size and lattice compatibility on the energy conversion figure-of-merit (FOM) of a phase-transforming ferroelectric system Ba0.95Ca0.05Ce0.005ZrxTi0.995−xO3 with Zr content ranging from 0.004 to 0.03. The results demonstrate that tuning grain size and lattice compatibility can significantly increase the FOM. The optimal composition Zr0.006 exhibits the highest FOM among its neighboring compositions, with a corresponding peak pyroelectric current density of 5.6 μA/cm2 generated from a temperature fluctuation of 30 °C at a temperature rate of 5 °C/s. This work provides a rational understanding of the effect of grain morphology and crystal structure on the pyroelectric properties for energy conversion.