Local Diverse Polarization Optimized Comprehensive Energy‐Storage Performance in Lead‐Free Superparaelectrics

Abstract

To realize the ultrahigh W rec , it is essential to improve the above factors simultaneously.Recently, numerous studies have shown that linear dielectrics, ferroelectrics, and antiferroelectrics are difficult to achieve breakthroughs in energy-storage performance owing to the lack of high-polarization genes, poor efficiency caused by high P r , unstable antiferroelectric phase and antiferroelectric-ferroelectric phase transition, respectively. [2] To further enhance the W rec , transforming ferroelectrics and antiferroelectrics into relaxors is a simple but effective method, leading to the decreased domain size and P r . Interestingly, the strategies for the formation of relaxors are diverse. For relaxor antiferroelectrics, ultrahigh W rec of 12.2 and 18.5 J cm −3 can be achieved in NaNbO 3 (NN)-based ceramics using nanodomain engineering, causing a diffuse antiferroelectric to ferroelectric phase transition behavior to reduce the possibility of breakdown by reducing large transient currents and volume changes. [3] However, relatively low efficiency (η < 80%) limits their actual applications. The strategy of constructing phase boundary was designed to obtain excellent comprehensive energy-storage properties in AgNbO 3 (AN)-based ceramics. [4] For relaxor ferroelectrics, many strategies, such as composition adjustment, [5] domain/nanodomain engineering, [6] high-entropy design [7] were proposed to improve the energy-storage performance. Unfortunately, in addition to high-entropy strategy, there is no effective design to realize ultrahigh energy storage density (W rec ≥ 10 J cm −3 ) in relaxor ferroelectrics, making them comparable to relaxor antiferroelectric energy storage ceramics in competitiveness and development potential. [3,8] The control of polarization, domain or polar nanoregions (PNRs) configuration is an amusing approach to design new dielectric materials with enhanced energy-storage performance. Unmatched temperature range, [9] nanoscale polarization mismatch and reconstruction, [10] and crossover region [11] were adopted to form different domain configurations such as coexisting Ti-rich and Bi-rich PNRs, and coexisting nanodomain and PNRs. However, low W rec (<4 J cm −3 ) and medium η (≈80%) were obtained in relaxors due to the insufficient E b , fast polarization saturation and the existence of large size nanodomains. It is common that enhanced relaxation can result in a decreased polarization, and some methods should be used Lead-free dielectric ceramics with ultrahigh energy-storage performance are the core components used in next-generation advanced pulse power capacitors. However, the low energy storage density largely hinders their development towards miniaturization, lightweight, and integration. Here, an effective strategy of constructing local diverse polarization is designed in superparaelectrics to realize an ultrahigh energy storage density of ≈10.59 J cm −3 as well as a large efficiency of ≈87.6%. The excellent comprehensive energy-storage performance is mainly attributed to the desi...

Delayed Polarization Saturation Induced Superior Energy Storage Capability of BiFeO3‐Based Ceramics Via Introduction of Non‐Isovalent Ions

“…The enhanced polarization (P max − P r ) can be illustrated on the basis of a simplified Landau-Devonshire ferroelectric theory model. The free energy (G) in different states can be expressed as a function of the polarization (P) as follows: [25,26] 2 4 6…”

Large Energy Capacitive High-Entropy Lead-Free Ferroelectrics

“…Pulse power capacitors are intensively used in microwave communications, hybrid electrical vehicles, medical devices, and other electronic power systems [1][2][3][4]. Lead-free dielectric ceramics, the core components of capacitors, are becoming high-profile energy storage materials owing to their distinctive features of high power density (P D ), ultrafast charge/discharge rate (t 0.9 ), and excellent operation stability [2,5].…”

Superior Capacitive Energy-Storage Performance in Pb-Free Relaxors with a Simple Chemical Composition

“…Relaxors have shown great promise for superior energy-storage performance, due to slim hysteresis with small remnant polarization ( P r ). Designing Pb-free relaxors containing highly polarizable ions with enhanced local polarization is a prevailing idea expected to achieve enhanced energy-storage properties. ,− Importantly, intrinsic polar structures, including the shapes, sizes, dipole patterns, and volume fraction of polar nanoregions substantially affect the properties. Based on rational chemical element substitution/doping and constructing solid solutions, various strategies, such as domain modification, , superparaelectric state, ,, high-entropy, , and phase structure control, − have been proposed.…”

“…Designing Pb-free relaxors containing highly polarizable ions with enhanced local polarization is a prevailing idea expected to achieve enhanced energy-storage properties. ,− Importantly, intrinsic polar structures, including the shapes, sizes, dipole patterns, and volume fraction of polar nanoregions substantially affect the properties. Based on rational chemical element substitution/doping and constructing solid solutions, various strategies, such as domain modification, , superparaelectric state, ,, high-entropy, , and phase structure control, − have been proposed. Furthermore, breakdown strength ( E b ) is also an important parameter, and can be improved through nanostructure construction, , grain refining, electrical microstructure control, , defect engineering, etc.…”