High Energy Storage Performance and Large Electrocaloric Response in Bi_0.5Na_0.5TiO₃–Ba(Zr_0.2Ti_0.8)O₃ Thin Films

Abstract

With regard to the global energy crisis and environmental pollution, ferroelectric thin films with unique polarization behavior have garnered considerable attention for energy storage and electrocaloric refrigeration. Herein, a series of (1 − x)Bi 0.5 Na 0.5 TiO 3 −xBa(Zr 0.2 Ti 0.8 )O 3 (x = 0.3−0.9; (1 − x)BNT−xBZT) films were fabricated on Pt(111)/Ti/SiO 2 /Si substrates. Incorporating BZT can tune the polarization behavior and phase transition temperature of BNT. A high recoverable energy density ≈ 82 J cm −3 and optimized efficiency ≈ 81% were realized for the (1 − x)BNT−xBZT thin film with x = 0.7. The thin film exhibits excellent stability in energy storage performance, a wide working frequency range (0.5−20 kHz), a broad operating temperature window (20−200 °C), and reduplicative switching cycles (10 7 cycles). In addition, the 0.5BNT−0.5BZT film exhibits a desirable electrocaloric effect with a large adiabatic temperature change (ΔT ≈ −22.9 K) and isothermal entropy change (ΔS ≈ 33.4 J K −1 kg −1 ) near room temperature under a moderate applied electric field of 2319 kV cm −1 . These remarkable performances signify that the (1 − x)BNT−xBZT system is a promising multifunctional electronic material for energy storage and solid-state cooling applications.

High Piezoelectricity in Eco-Friendly NaNbO3-Based Ferroelectric Relaxor Ceramics via Phase and Domain Engineering

“…The room-temperature dielectric constant (ε r ) of NN-10BTS- x NS ceramics can be observed to increase gradually with increasing NS content, and T m (temperature at the maximum value of ε r ) shifts significantly toward lower temperatures and becomes progressively relaxed, indicating a continuous phase transition process. , The modified Curie’s law used to calculate γ for ferroelectric materials can be used to describe the relaxor behaviors of NN-10BTS- x NS ceramics, as shown in Figure S1. The transition from a normal ferroelectric material to an ideal relaxor ferroelectricity is usually considered to correspond to a change of γ from 1 to 2, respectively . Therefore, the calculated γ value gradually increases from 1.52 to 1.91 as the NS content increases, which further indicates the enhanced ferroelectric relaxation characteristics of NN-10BTS- x NS ceramics.…”

“…Interestingly, besides T m , another indistinct dielectric peak of NN-10BTS- x NS ceramics at low NS content (i.e., x ≤ 1.5) can be successfully observed by the temperature-dependent ε r of NN-10BTS- x NS ceramics after polarization (Figure d). After poling, the partial Relaxor Ferroelectric state will be induced into the normal ferroelectric state, resulting in enhanced ferroelectricity and more obvious phase transition characteristics, thereby allowing another indistinct dielectric peak of the NN-10BTS- x NS ceramics to be seen more clearly in the polarized samples with features similar to those of the BNT-based non-ergodic relaxor ceramics. ,− …”

Ultrahigh Energy Density of Antiferroelectric PbZrO3‐Based Films at Low Electric Field

“…This is due to the fact that in order to enhance E b , the polarization of the material will be reduced, which in turn lowers the energy density. In contrast, the studied PLZ(5) and PSZ (5) films are found to possess high energy density far superior to other dielectric materials at [6,26,30,[35][36][37][38][39][40][41][42][43][44][45][46] f) Temperature dependent dielectric constant and dielectric loss for PLZ(5) films. g) Cycle reliability, h) frequency stability, and i) temperature stability of energy storage properties for representative PLZ(5) films.…”

Substantially Enhanced Electrocaloric Effect in Ba(Zr0.2Ti0.8)O3 Lead-Free Ferroelectric Ceramics via Lattice Stress Engineering

“…Electrocaloric effect (ECE), i.e., the adiabatic temperature change and isothermal entropy change arising from dipole orientation and phase transition induced by electric fields (Δ E ), has attracted a great deal of attention. , Cooling devices based on ECE are highly efficient solid-state cooling technology with the advantages of compact device configurations, lightweight, and environment-friendly. − In recent years, a high ECE has been explored in dielectric thin films, − bulk ceramics, − and polymers. − In particular, bulk ceramics hold significant potential for practical cooling applications owing to their high EC strength (Δ T /Δ E ), simple preparation process, and low cost. However, the working electric field of bulk ceramics is still inferior to those of polymers and thin films, which means that the ECE strength in bulk ceramics needs to be further enhanced to guarantee enough Δ T for the practical use of cooling devices.…”