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

Abstract

Electrostatic capacitors are emerging as a highly promising technology for large‐scale energy storage applications. However, it remains a significant challenge to improve their energy densities. Here, an effective strategy of introducing non‐isovalent ions into the BiFeO3‐based (BFO) ceramic to improve energy storage capability via delaying polarization saturation is demonstrated. Accordingly, an ultra‐high energy density of up to 7.4 J cm−3 and high efficiency ≈ 81% at 680 kV m−1 are realized, which is one of the best energy storage performances recorded for BFO‐based ceramics. The outstanding comprehensive energy storage performance is attributed to inhibiting the polarization hysteresis resulting from generation ergodic relaxor zone and random field, and generating highly‐delayed polarization saturation with continuously‐increased polarization magnitudes with the electric field of supercritical evolution. The contributions demonstrate that delaying the polarization saturation is a consideration for designing the next generation of lead‐free dielectric materials with ultra‐high energy storage performance.

High-Entropy Strategy for Improved Mechanical and Energy Storage Properties in BaTiO3–BiFeO3-Based Ceramics

“…47 The regions that range in size from 3 to 5 nm are likewise in line with the PNR results that have been previously published; these regions often have lower switching energies and are diagnostic of RFE. 1,11 Moreover, PNRs that manifest as Moiréfringe structures are prominently visible in HR-TEM (Figure 6c). These structures indicate localized polar lattice distortion and result from the interference of two overlaid lattice patterns with mismatched orientations.…”

“…In order to understand the effect of the SMZTN content on the breakdown electric field ( E b ) of the BF-BT matrix, the E b values of BF-BT-SMZTN ceramics were featured by the Weibull distribution. Generally, the Weibull distribution can be expressed by the following equations: where E i denotes the specifc breakdown strength of ceramic samples, i is the ordinal number of ceramic samples, and n represnts the total amount of ceramic samples. The intersection of the fitted line and Y i = 0 denotes the theoretical E b value.…”

“…Dielectric capacitors have several advantages over batteries and electrochemical capacitors (supercapacitors), such as ultrahigh power density (MW kg –1 ), mechanical and thermal stability, and faster charge and discharge rates (<1 μs). These advantages make dielectric capacitors better suited for high-power/pulse power technologies in transportation (electric cars and trains) and the Internet of Things (IoT). − One major drawback of dielectric capacitors is their very poor energy storage capacity as compared to electrochemical or other emerging energy storage devices . To fulfill the demands of the integration of electronic devices, a range of modulation techniques are available to improve their energy densities ( W ) and energy-storage efficiencies (η). , …”

Tailoring Phase Fraction Induced Saturation Polarization Delay for High-Performance BaTiO3-Based Relaxed Ferroelectric Capacitors

“…As a result, the macroscopic polarization in such structures only occurs under high electric fields and low temperatures, which is favor to delayed saturation polarization. 36 The hysteresis area <A> of BBNT-xBLTT ceramics varied with different electric fields is examined, as shown in Figure 3d−f and Figure S4. The relationship between the hysteresis area and electric field can be described by the scaling law (<A> ∝ E α ), 37,38 where the parameter <A> with a characteristic of The value of the exponent α is mainly determined by the domain state and the mechanism of polarization switching.…”

“…A large activation energy ( E a ) value indicates a weakly coupled polar structure in RFEs. As a result, the macroscopic polarization in such structures only occurs under high electric fields and low temperatures, which is favor to delayed saturation polarization …”