Large Energy Capacitive High-Entropy Lead-Free Ferroelectrics

Abstract

Advanced lead-free energy storage ceramics play an indispensable role in next-generation pulse power capacitors market. Here, an ultrahigh energy storage density of ~ 13.8 J cm−3 and a large efficiency of ~ 82.4% are achieved in high-entropy lead-free relaxor ferroelectrics by increasing configuration entropy, named high-entropy strategy, realizing nearly ten times growth of energy storage density compared with low-entropy material. Evolution of energy storage performance and domain structure with increasing configuration entropy is systematically revealed for the first time. The achievement of excellent energy storage properties should be attributed to the enhanced random field, decreased nanodomain size, strong multiple local distortions, and improved breakdown field. Furthermore, the excellent frequency and fatigue stability as well as charge/discharge properties with superior thermal stability are also realized. The significantly enhanced comprehensive energy storage performance by increasing configuration entropy demonstrates that high entropy is an effective but convenient strategy to design new high-performance dielectrics, promoting the development of advanced capacitors "Image missing".

A review on structure–property relationships in dielectric ceramics using high‐entropy compositional strategies

“…This disruption resulted in the formation of smaller PNRs and significantly increased the maximum polarization strength P max . 77 The weakly coupled PNRs, presence of polymorphic oxygen octahedra, TA B L E 1 Energy storage density, breakdown field strength, and energy storage efficiency of the high-entropy dielectric.…”

“…Another design concept aimed to disrupt the long‐range ordered ferroelectric state by introducing an enhanced local random field was utilized in (Bi 0.5 Na 0.5 )(Ti 1−2 x Fe x Nb x )O 3 ( x = 1/3) ceramic using NaNbO 3 , (Bi 0.5 Na 0.5 )TiO 3 , and BiFeO 3 (the design concept is shown in Figure 7). This disruption resulted in the formation of smaller PNRs and significantly increased the maximum polarization strength P max 77 . The weakly coupled PNRs, presence of polymorphic oxygen octahedra, and higher grain boundary density collectively contributed to a higher breakdown field strength E b .…”

Excellent Energy‐Storage Performance in Lead‐Free Capacitors with Highly Dynamic Polarization Heterogeneous Nanoregions

“…The emergence of coexisting in-phase and antiphase oxygen octahedral tilts could be mainly attributed by the introduction of large-tolerance BFN causing the obvious stabilization of T phase at room temperature, which can enhance the disturbance degree of the system, that is, the random field. [21] Furthermore, more electric energy can be absorbed by oxygen octahedral tilt distortions during the process of establishing longrange ferroelectric order from PNRs under electric fields, leading to more delayed polarization saturation behavior. [2] As shown in Figure 3e, a large number of randomly distributed Moiré fringe structures rather than nanodomains can be clearly found and most of their sizes are ≈3 to 6 nm.…”

“…[11,19,20] For band structure, selecting a matrix with a high bandgap (E g ) or introducing high-E g solutions can improve the intrinsic breakdown strength to enhance E b . [21,22] Compared to the above structural regulation pathways, the regulation of local polarization structure is more complex and challenging.…”

AgNbO3-Based Multilayer Capacitors: Heterovalent-Ion-Substitution Engineering Achieves High Energy Storage Performances

“…Besides, the demands for miniaturization, compactness, and integration of electronic devices make it urgent to develop dielectric capacitors with high energy storage density. Therefore, up to now, considerable efforts have been consistently dedicated to improving their energy storage density. − …”