An analysis of lead-free (Bi0.5Na0.5)0.915-(Bi0.5K0.5)0.05Ba0.02Sr0.015TiO3 ceramic for efficient refrigeration and thermal energy harvesting

TLDR

The study introduces a generalized solid‑state refrigeration cycle contrasting the ferroelectric Ericson cycle. The article demonstrates the colossal energy harvesting capability of a lead‑free (Bi₀.₅Na₀.₅)₀.₉₁₅-(Bi₀.₅K₀.₅)₀.₀₅Ba₀.₀₂Sr₀.₀₁₅TiO₃ ceramic using the Olsen cycle while introducing a generalized solid‑state refrigeration cycle. The Olsen cycle exploits a temperature‑induced polarization change when a unipolar electric field is applied to ferroelectric ceramics. The maximum harvestable energy density is 1523 J/L (1523 kJ/m³) under 20–160 °C and 0.1–4 MV/m, which is 1.7 times higher than the best reported for lanthanum‑doped lead zirconate titanate thin films.

Abstract

This article demonstrates the colossal energy harvesting capability of a lead-free (Bi0.5Na0.5)0.915-(Bi0.5K0.5)0.05Ba0.02Sr0.015TiO3 ceramic using the Olsen cycle. The maximum harvestable energy density estimated for this system is found to be 1523 J/L (1523 kJ/m3) where the results are presented for extreme ambient conditions of 20–160 °C and electric fields of 0.1–4 MV/m. This estimated energy density is 1.7 times higher than the maximum reported to date for the lanthanum-doped lead zirconate titanate (thin film) system. Moreover, this study introduces a generalized and effective solid state refrigeration cycle in contrast to the ferroelectric Ericson refrigeration cycle. The cycle is based on a temperature induced polarization change on application of an unipolar electric field to ferroelectric ceramics.