Ultrahigh Energy Storage Density and Efficiency of Lead‐Free Dielectrics with Sandwich Structure

Abstract

Lead‐free dielectric capacitors have attracted significant research interest for high‐power applications due to their environmental benefits and ability to meet the demanding performance requirements of electronic devices. However, the development of lead‐free ceramic dielectrics with outstanding energy storage performance remains a challenge. In this study, environmentally friendly ceramic dielectrics with sandwich structures are designed and fabricated to improve energy storage performance via the synergistic effect of different dielectrics. The chemical compositions of the outer and middle layers of the sandwich structure are 0.35BiFeO3‐0.65SrTiO3 and Bi0.39Na0.36Sr0.25TiO3, respectively. The experimental and theoretical simulation results demonstrate that the breakdown strength is over 700 kV cm−1 for prepare sandwich structure ceramics. As a result, an ultrahigh recoverable energy storage density of 9.05 J cm−3 and a near‐ideal energy storage efficiency of 97% are simultaneously achieved under 710 kV cm−1. Furthermore, the energy storage efficiency maintains high values (≥ 96%) within 1–100 Hz and the power density as high as 188 MW cm−3 under 400 kV cm−1. These results indicate that the designed lead‐free ceramics with a sandwich structure possess superior comprehensive energy storage performance, making them promising lead‐free candidates in the energy storage field.

Robust Energy Storage Property of La-Doped PZT Films Within a Wide Temperature Range

“…Energy storage capacitors with wide temperature stability have attracted much attention in high-power systems and high-frequency pulsed devices due to their high dielectric constant, excellent energy storage performance, along with fast charging and discharging performance. − Antiferroelectric (AFE) films have been widely explored for applications in energy storage devices owing to their tunable dynamic dipoles under external excitation, including electric fields and temperature. Up to now, most of the research has focused on AFE bulk ceramics and films.…”

Achieving High Energy Storage Performance under a Low Electric Field in KNbO3-Doped BNT-Based Ceramics

“…The formula for calculating W rec , W tot , and energy storage efficiency (η) is as follows , W normalr normale normalc = ∫ P normalr P max E .25em normald P W normalt normalo normalt = ∫ 0 P max E .25em normald P η = W r e c W t o t × 100 % where E and P max denote the electric field and maximum polarization, respectively. From eq , it may be noted that high breakdown field strength ( E b ), small hysteresis return area, and large polarization difference (Δ P ) enable the sample to reach high W rec . − …”

Strong Local Polarization Fluctuations Enabled High Electrostatic Energy Storage in Pb-Free Relaxors

“…Among dielectrics, relaxor ferroelectrics (RFEs) are particularly promising due to their high polarization (P m ), low P r (corresponding to large ΔP, where ΔP = P m − P r ), and low hysteresis. These key features of RFEs arise from their nanoscale polar structures, represented as polar nanoregions (PNRs), 28,29 which enable to respond rapidly and effectively to external E. By weakening the intercoupling and reducing the energy barrier between PNRs through various tactics, such as reducing their size or volume fraction, 1,30,31 constructing polymorphic symmetries, 7,32,33 assembling different configurations, 34,35 it is possible to reduce H and enhance E B , leading to improvements in both η and W rec of RFEs. These approaches are typically implemented by merging nonferroelectrically or weakly ferroelectrically active ions or constituents into a ferroelectric (FE) matrix.…”