Positive and negative electrocaloric effect in the direct and indirect characterization of NaNbO<sub>3</sub>-based ceramics with tetragonal–cubic phase boundary

Yin, Jie; Zhao, Lin; Wu, Bo; Ma, Jian; Ergu, Daji; Wu, Jiagang

doi:10.1039/d2tc03915j

Cited by 10 publications

(4 citation statements)

References 44 publications

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“…Figure 8A,B shows the comparison of Δ T and T span with those of other electrocaloric ceramics under the electric fields of 20–100 kV/cm, which demonstrates that the ceramics developed in the current paper possess higher Δ T and wider T span . 7, 8,30,38,39,54,56–67 …”

Section: Resultsmentioning

confidence: 99%

“…Figure 8A,B shows the comparison of ΔT and T span with those of other electrocaloric ceramics under the electric fields of 20-100 kV/cm, which demonstrates that the ceramics developed in the current paper possess higher ΔT and wider T span . 7,8,30,38,39,54,[56][57][58][59][60][61][62][63][64][65][66][67] Furthermore, the ΔT of BCT-0.13Sn and BCT-0.15Sn were measured by the direct method where the heat flow was under the electric fields of 10, 20, and 25 kV/cm to minimize the testing errors. Finally, the ΔQ value was subsequently determined by integrating the areas under the absorption and exothermic peaks and comparing them with the reference heat.…”

Section: Adiabatic Temperature Changementioning

confidence: 99%

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Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

Feng,

Hao,

et al. 2024

J Am Ceram Soc.

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A large adiabatic temperature change along with a wide operating temperature region is usually required for the electrocaloric materials to fulfill their refrigeration function. In general, doping foreign ions into BaTiO3 is the frequently utilized strategy in order to obtain excellent electrocaloric materials for the practical application. In the current paper, BaTiO3 lead‐free ferroelectric ceramics were doped by Ca2+ and Sn4+ simultaneously in order to generate a coexistence state at room temperature, where ferroelectric domains and nanodomains exit. As a result, a large polarization and a wide operating temperature range were finally induced. It is found that Ba0.9Ca0.1Ti0.85Sn0.15O3 has a maximum adiabatic temperature change of 0.85 K and an excellent working temperature region (65 K, ∆T > 90% Tmax) was achieved under an electric field of 50 kV/cm. The above phenomenon indicates that the modified BaTiO3 ceramics can be a good potential electrocaloric material in the state of cross‐existence of ferroelectric domains and nanodomains.

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Section: Resultsmentioning

confidence: 99%

Section: Adiabatic Temperature Changementioning

confidence: 99%

Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

Feng,

Hao,

et al. 2024

J Am Ceram Soc.

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“…As a result, both T and C phases (stable at high temperatures) of NN-based ceramics are also stable at ambient temperature. [22,23] To further clarify the phase structure characteristics in Yb/Tm-xZTH ceramics, the Rietveld refinement technique was used and the results are shown in Figure 2c,d and Figure S1 (Supporting Information). At x = 0.01, the proportion of the T phase (73.6%) dominates.…”

Section: Local Structure and Optical Transparencymentioning

confidence: 99%

Superior Energy Storage Capability and Fluorescence Negative Thermal Expansion of NaNbO₃‐Based Transparent Ceramics by Synergistic Optimization

Zeng,

Lin,

Chen

et al. 2024

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Transparent dielectric ceramics are splendid candidates for transparent pulse capacitors (TPCs) due to splendid cycle stability and large power density. However, the performance and service life of TPCs at present are threatened by overheating damage caused by dielectric loss. Here, a cooperative optimization strategy of microstructure control and superparaelectric regional regulation is proposed to simultaneously achieve excellent energy storage performance and real‐time temperature monitoring function in NaNbO3‐based ceramics. By introducing aliovalent ions and oxides with large bandgap energy, the size of polar nanoregions is continuously reduced. Due to the combined effect of increased relaxor behavior and fine grains, excellent comprehensive performances are obtained through doping appropriate amounts of Bi, Yb, Tm, and Zr, Ta, Hf in A‐ and B‐sites of the NaNbO3 matrix, including recoverable energy storage density (5.39 J cm−3), extremely high energy storage efficiency (91.97%), ultra‐fast discharge time (29 ns), and superior optical transmittance (≈47.5% at 736 nm). Additionally, the phenomenon of abnormal fluorescent negative thermal expansion is realized due to activation mechanism of surface phonon at high temperatures that can promote the formation of [Yb···O]‐Tm3+ pairs, showing great potential in real‐time temperature monitoring of TPCs. This research provides ideas for developing electronic devices with multiple functionalities.

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“…Using this composition and structure, Torelló et al and Wang et al obtained significant temperature spans of 13 and 5.2 K, respectively, between the cold and hot ends in their prototype electrocaloric devices [7,8]. However, the lead-based composition would take an environmental toll, which makes lead-free ECE materials the potential alternatives, including BaTiO 3 , Bi 0.5 Na 0.5 TiO 3 (NBT), NaNbO 3 , and BiFeO 3 materials [2,3,[9][10][11][12].…”

mentioning

confidence: 99%

Enhanced electrocaloric effect over a broad temperature range in lead‐free Na_0.5Bi_0.5TiO₃‐based relaxor ferroelectrics via doping with Bi(Mg_0.5Zr_0.5)O₃

Niu,

Jiang,

Lai

et al. 2023

IET Nanodielectrics

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With an increasing demand for environmentally friendly refrigeration, the solid‐state refrigeration based on the electrocaloric effect (ECE) has been drawn extensive attention. It is a challenge to maintain a large adiabatic temperature change (∆T) over a broad temperature span. Herein, the authors designed and synthesised (0.74‐x) Na0.5Bi0.5TiO3‐0.06BaTiO3‐0.2SrTiO3‐xBi(Mg0.5Zr0.5)O3 (abbreviated as NBT‐xBMZ) (x = 0, 0.02, 0.04, 0.06 and 0.08) lead‐free relaxor ferroelectrics. Their microstructures, dielectric properties, ferroelectric properties, ECEs and the structure‐property relationships were investigated. Via doping with BMZ, an enhanced relaxor feature and a wider temperature range where multi‐phases coexist were achieved. The relaxor ferroelectric characteristics were illustrated using the Vogel‐Fulcher relation. The indirectly calculated ECE results showed that the optimal ΔT of 1.11 K was obtained for the x = 0.02 sample at 90°C and 70 kV/cm over a wide Tspan of 120°C, providing a potential ECE material. The direct ECE results procured using thermocouple indicated that the maximal ∆T of 2.14 K and ∆T/∆E of 0.31 K m/MV were achieved in the same sample at 70°C and 7 MV/m and the variation trend of ECE results was consistent with the indirect results. Moreover, the multi‐phases coexistent strategy can be extended to other materials system to generate a large ΔT over a wide temperature range.

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Positive and negative electrocaloric effect in the direct and indirect characterization of NaNbO₃-based ceramics with tetragonal–cubic phase boundary

Abstract: A novel phenomenon of negative ΔT is observed during indirect characterization, while positive values for direct characterization.

Cited by 10 publications

References 44 publications

Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

Superior Energy Storage Capability and Fluorescence Negative Thermal Expansion of NaNbO₃‐Based Transparent Ceramics by Synergistic Optimization

Enhanced electrocaloric effect over a broad temperature range in lead‐free Na_0.5Bi_0.5TiO₃‐based relaxor ferroelectrics via doping with Bi(Mg_0.5Zr_0.5)O₃

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Positive and negative electrocaloric effect in the direct and indirect characterization of NaNbO3-based ceramics with tetragonal–cubic phase boundary

Abstract: A novel phenomenon of negative ΔT is observed during indirect characterization, while positive values for direct characterization.

Cited by 10 publications

References 44 publications

Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

Superior Energy Storage Capability and Fluorescence Negative Thermal Expansion of NaNbO3‐Based Transparent Ceramics by Synergistic Optimization

Enhanced electrocaloric effect over a broad temperature range in lead‐free Na0.5Bi0.5TiO3‐based relaxor ferroelectrics via doping with Bi(Mg0.5Zr0.5)O3

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Positive and negative electrocaloric effect in the direct and indirect characterization of NaNbO₃-based ceramics with tetragonal–cubic phase boundary

Superior Energy Storage Capability and Fluorescence Negative Thermal Expansion of NaNbO₃‐Based Transparent Ceramics by Synergistic Optimization

Enhanced electrocaloric effect over a broad temperature range in lead‐free Na_0.5Bi_0.5TiO₃‐based relaxor ferroelectrics via doping with Bi(Mg_0.5Zr_0.5)O₃