Enhanced energy-storage performance and electrocaloric effect in compositionally graded Pb (1−3x/2) La x Zr 0.85 Ti 0.15 O 3 antiferroelectric thick films

Abstract The compositionally graded multilayer Pb( 1−3 x /2 )La x Zr 0.85 Ti 0.15 O 3 (PLZT) antiferroelectric (AFE) thick films were deposited on LaNiO 3 /Si (100) substrates by using a sol–gel method. The effect of gradient sequence on dielectric properties, energy-storage performance, and electrocaloric effect (ECE) was investigated in detail. It is found that the compositionally graded films exhibited a significant enhancement in dielectric properties, energy-storage performance and ECE, which was, in contrast to the single-composition PLZT film, contributed by the strain and the gradient of polarization near the interfaces between the adjacent layers. A recoverable energy-storage density of 44 J/cm 3 and efficiency of 71% was obtained in the up-graded PLZT AFE thick film at 1950 kV/cm. A giant reversible adiabatic temperature change of ∆ T =28 °C at room temperature at 900 kV/cm was also achieved in the up-graded film. Moreover, all the thick films displayed a small leakage current density below 10 −6  A/cm 2 at room temperature. Thus, the compositionally graded PLZT AFE thick films with a large recoverable energy-storage density and a giant ECE could be a potential candidate for the applications in high energy-storage density capacitors and cooling devices.