Electrocaloric effect and pyroelectric energy harvesting in diffuse ferroelectric Ba(Ti1-xCex)O3 ceramics

In the present work Ba(Ti1-xCex)O3 ceramics are prepared through a standard solid-state sintering process. Crystal structures, dielectric properties, ferroelectric properties and electrocaloric effects are exactly studied. Ce4+ ions cannot entirely enter the position of Ti4+, so some impure phases are generated. The diffusivity of phase transition is strengthened by substituting Ti4+ with Ce4+ cations. The maximal pyroelectric coefficient decreases, and the extent of corresponding temperature deviating from the dielectric peak temperature to higher temperature increases with increasing the content of cerium cations. The adiabatic temperature change and isothermal entropy change display the same tendency as that of the pyroelectric coefficient. The Ba(Ti0.9Ce0.1)O3 ceramic shows the largest adiabatic temperature change of 0.41 K and the largest isothermal entropy change of 0.45 J/(kg·K) among the ceramics. Accordingly, the adiabatic temperature change responsivity is 0.090 × 10−6 K·m/V, and the isothermal entropy change responsivity is 0.100 × 10−6 J·m/(kg·K·V). For individual composition, the absolute value of pyroelectric coefficient decreases with increasing the magnitude of applied electric field, and the temperature of maximal pyroelectric coefficient deviates from the dielectric peak temperature shifts to higher temperature. Ba(Ti0.9Ce0.1)O3 ceramics show the largest pyroelectric energy density of 0.14 J/cm3 among all compositions.