Role of Na in structural and polarization characteristics of prototype lead-free K0.5Na0.5NbO3 piezoelectrics

Wang, Na; Yao, Yonghao; Liu, Hui; Chen, Jun

doi:10.1016/j.scriptamat.2024.116032

Cited by 3 publications

(1 citation statement)

References 34 publications

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“…A clear separation is observed in the Bi–O pairs, resulting from the strong hybridization between the Bi 6s 2 and O 2p orbitals. Asymmetric peaks are also observed in the Na–O pairs, which is thought to be due to the steric effect caused by the smaller ionic radius of Na + . , On the other hand, Ba–O exhibits a single symmetric peak. The statistical analysis of the orientation of polar displacement vectors is presented in the form of a stereographic projection along [001] c .…”

Section: Resultsmentioning

confidence: 99%

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

Sun,

Liu,

Zhang

et al. 2024

J. Am. Chem. Soc.

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Electrostatic energy-storage ceramic capacitors are essential components of modern electrified power systems. However, improving their energy-storage density while maintaining high efficiency to facilitate cutting-edge miniaturized and integrated applications remains an ongoing challenge. Herein, we report a record-high energy-storage density of 20.3 J cm −3 together with a high efficiency of 89.3% achieved by constructing a relaxor ferroelectric state with strongly enhanced local polarization fluctuations. This is realized by incorporating highly polarizable, heterovalent, and large-sized Zn and Nb ions into a Bi 0.5 Na 0.5 TiO 3 −BaTiO 3 ferroelectric matrix with very strong tetragonal distortion. Element-specific local structure analysis revealed that the foreign ions strengthen the magnitude of the unit-cell polarization vectors while simultaneously reducing their orientation anisotropy and forming strong fluctuations in both magnitude and orientation within 1−3 nm polar clusters. This leads to a particularly high polarization variation (ΔP) of 72 μC cm −2 , low hysteresis, and a high effective polarization coefficient at a high breakdown strength of 80 kV mm −1 . This work has surpassed the current energy density limit of 20 J cm −3 in bulk Pb-free ceramics and has demonstrated that controlling the local structure via the chemical composition design can open up new possibilities for exploring relaxors with high energy-storage performance.

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Section: Resultsmentioning

confidence: 99%

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

Sun,

Liu,

Zhang

et al. 2024

J. Am. Chem. Soc.

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Multicomponent modified perovskite lead-free KNN ceramic to establish R–T phase boundary near room temperature for energy acquisition and harvesting

Yadav,

Sinha,

Shukla

et al. 2024

J Mater Sci: Mater Electron

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Chemical Bonding Engineering: Insights into Physicochemical Performance Optimization for Energy-Storage/Conversion

Zhou,

Wei,

Zhou

et al. 2024

Acc. Mater. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS: Chemical bonding is fundamental in determining the physicochemical properties of the materials. Establishing correlations between chemical bonding and these properties may help identify potential materials with unique advantages or guide the composition design for improving the performance of functional materials. However, there is a lack of literature addressing this issue. This Account examines how chemical bonding engineering affects the performance optimization of four widely used or investigated functional materials that are applied in energy-storage/conversion fields, including thermoelectrics, piezoelectrics, lithium-ion batteries (LIBs), and catalysts. The key issues of these materials and correlations between chemical bonding and properties are briefly summarized. First, electron−phonon coupling hinders thermoelectric performance optimization, representing one of the main issues in the thermoelectric field that needs to be addressed. The role of chemical bonding engineering in electronic and phonon transport is discussed, highlighting how factors such as covalency, electronegativity differences, bond strength, and bond length affect carrier mobility and lattice thermal conductivity. We found that electronic and phonon transport properties can be tuned by modifying the chemical bonding of thermoelectric materials. Second, the performance of perovskite piezoelectric materials is governed by their phase structure, which is closely associated with ABO 3 lattice distortion. However, clarifying the correlations between perovskite distortion and chemical bonding has long been challenging. The effects of chemical bonding on perovskite distortion and ferroelectric/piezoelectric response are summarized, focusing on lead-free piezoelectric materials. The roles of ionic radii and electronic structures in the ionocovalent bonding between A-/B-site cations and oxygen anions, as well as the stability of perovskite structures, are discussed. These factors are proven to significantly affect the phase structure and piezoelectric response. Third, during LIB operation, various chemical reactions occur within the electrodes and at the electrode/electrolyte interface, leading to the formation of new reversible or irreversible products. These structural and compositional changes signify a continuous evolution of the chemical bonds within the LIB system. Strategies to enhance the stability of high-capacity electrodes through the development of chemical cross-linker binders are summarized. Additionally, the impact of chemical bonds on the electrochemical stability and lithium-transport capabilities of solid-state electrolytes is also explored. Consequently, deliberately controlling chemical bonds is crucial for optimizing the overall electrochemical performance of LIBs, including parameters such as energy density, cycling lifespan, and fast-charging capabilities.Fourthly, improving the catalytic activity of catalysts for chemical reactions is the main problem in catalysis. This A...

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Role of Na in structural and polarization characteristics of prototype lead-free K0.5Na0.5NbO3 piezoelectrics

Cited by 3 publications

References 34 publications

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

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

Multicomponent modified perovskite lead-free KNN ceramic to establish R–T phase boundary near room temperature for energy acquisition and harvesting

Chemical Bonding Engineering: Insights into Physicochemical Performance Optimization for Energy-Storage/Conversion

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