Thermomechanical Energy Conversion Potential of Lead‐Free 0.50Ba(Zr0.2Ti0.8 )O3–0.50(Ba0.7Ca0.3)TiO3 Bulk Ceramics

Abstract

AbstractWhen employed appropriately, ferroelectric materials present themselves as one of the most efficient means of waste (thermal/mechanical) energy scavenging. A large conversion potential can be obtained when appropriate materials are combined with high‐field actuation (Ericsson cycle). However, waste energy rarely presents itself in an isolated form (heat or vibration). There is also a distinct lack of systems capable of simultaneous thermomechanical energy conversion, especially in the low‐frequency range. In this regard a systematic approach to the concept of combined energy harvesting and storage potential of a singular material system is presented. Polarization versus electric field hysteresis loops were gathered as a function of temperature, uniaxial compressive stress, and electric field. Thereafter, a theoretical assessment was made to the effect of the biased and unbiased energy conversion potential of 0.50 Ba(Zr0.2Ti0.8)O3–0.50 (Ba0.7Ca0.3)TiO3 bulk lead‐free ferroelectric material. Maximum energy conversion potentials of 150 and 210 kJ m−3 were obtained for thermal (5 MPa, 24–96 °C) and mechanical cycles (24 °C, 5–160 MPa), respectively. A slightly improved performance of 220 kJ m−3 was obtained under simultaneous depolarization, despite performance degradation through individual biasing. However, the energy‐storage density improved by 100 % (80 kJ m−3) and 50 % (60 kJ m−3), respectively, when operated under elevated stress (60 MPa) and temperature (90 °C). Results are indicative of a singular material system that could be used for combined thermomechanical energy conversion and on‐board storage capacity.