Abnormal Grain Growth as a Method To Enhance the Thermoelectric Performance of Nb-Doped Strontium Titanate Ceramics

Tkach, Alexander; Resende, João; Saravanan, K.; Costa, Maria Elisabete V.; Díaz-Chao, P.; Guilmeau, Emmanuel; Okhay, Olena; Vilarinho, Paula M.

doi:10.1021/acssuschemeng.8b03875

Cited by 31 publications

(15 citation statements)

References 27 publications

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“…Energy filtering effects in the fine size STN20 further reportedly lead to an increase in Seebeck coefficient with temperature. The power factor of this material obtained was 13.4 µW/K 2 cm which is comparable with that of state-of-the-art thermoelectric material Bi 2 Te 3 and finally leading to a ZT of 0.36 at 970 K [31]. Meanwhile, a much simpler approach was followed by Ekren et al where a fixed amount (0.5 wt%) of B 2 O 3 and 0.3 wt% ZrO 2 were composited with Sr 0.9 Nb 0.1 TiO 3 to obtain 1400 S/cm at room temperature and ~ 200 S/cm at 1273 K. A drastic improvement in electrical conductivity was seen on just 0.3 wt% addition of ZrO 2 .…”

Section: Srtiosupporting

confidence: 71%

Review on texturization effects in thermoelectric oxides

Prasad

Bhame

2020

Mater Renew Sustain Energy

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Sustainable energy sources and energy-harvesting technologies have been researched for decades. Thermoelectric conversion is currently one of the primary foci in this area. Thermoelectric research has been concentrated into two parts-(i) strategies to enhance the efficiency of existing thermoelectric materials and (ii) development of new materials with promising thermoelectric parameters. Although such strategies have led to the improvement of thermoelectric non-oxide-based materials, the limitations possessed by them does not allow to be used at high temperatures. Due to the same reason, oxide-based materials have gained much attention. Here, we discuss about the oxide thermoelectric materials in detail and the effect of texturization on their morphology and transport properties. There is a lot of scope available for such class of materials for high-temperature applications.

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Section: Srtiosupporting

confidence: 71%

Review on texturization effects in thermoelectric oxides

Prasad

Bhame

2020

Mater Renew Sustain Energy

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“…As the figure shows, the obtained ZT values were mainly in the range of 0.1–0.4, representing some of the best values ever reported. Some of the ZT values ( ZT > 0.35) are summarized in Table . ,− In each reference, the selected TE parameters occurred at the same temperature as the best ZT value. In these studies, reduction atmosphere sintering (5 or 10% H 2 ) was commonly used to boost the electrical conductivity of the materials.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures

Qin

Lou

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

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La-doped strontium titanite (Sr 0.9 La 0.1 TiO 3 ) is a promising candidate for n-type oxide thermoelectric materials. However, the ZT values of this material are low, leading to low conversion efficiency. Improvements in this efficiency are required. In this work, a high ZT value of 0.50 was obtained for Sr 0.9 La 0.1 TiO 3 ceramic samples by adding 10 wt % Bi 2 O 3 sintering aids and 20 wt % nanosized Ti powders to the matrix material. Although Ti was oxidized to TiO 2 during the sintering process, nanoscale phase interfaces were beneficial for phonon scattering and thermal conductivity reduction. Nanosized metallic Bi and Bi 2 O 3 particles were observed. These two factors played an important role in reducing the thermal conductivity from 2.5 W/(m K) at room temperature to 1.31 W/(m K) at 1073 K. Nanostructure control using nanosized metal powders as additives combined with the Bi 2 O 3 sintering aid paves a way for enhancement of thermoelectric properties of oxide thermoelectric materials.

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“…Thus, AGG studies remain an area of active research with an emphasis on electrical steels [9][10][11]. Furthermore, recent investigations deal with AGG during sintering [33][34][35][36] where, however, porosity plays a critical role [37]. Other studies consider the role of local plastic strain on the formation of abnormal grains [24,38,39].…”

Section: Introductionmentioning

confidence: 99%

Phase Field Modelling of Abnormal Grain Growth

2019

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Heterogeneous grain structures may develop due to abnormal grain growth during processing of polycrystalline materials ranging from metals and alloys to ceramics. The phenomenon must be controlled in practical applications where typically homogeneous grain structures are desired. Recent advances in experimental and computational techniques have, thus, stimulated the need to revisit the underlying growth mechanisms. Here, phase field modelling is used to systematically evaluate conditions for initiation of abnormal grain growth. Grain boundaries are classified into two classes, i.e., high- and low-mobility boundaries. Three different approaches are considered for having high- and low-mobility boundaries: (i) critical threshold angle of grain boundary disorientation above which boundaries are highly mobile, (ii) two grain types A and B with the A–B boundaries being highly mobile, and (iii) three grain types, A, B and C with the A–B boundaries being fast. For these different scenarios, 2D simulations have been performed to quantify the effect of variations in the mobility ratio, threshold angle and fractions of grain types, respectively, on the potential onset of abnormal grain growth and the degree of heterogeneity in the resulting grain structures. The required mobility ratios to observe abnormal grain growth are quantified as a function of the fraction of high-mobility boundaries. The scenario with three grain types (A, B, C) has been identified as one that promotes strongly irregular abnormal grains including island grains, as observed experimentally.

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Abnormal Grain Growth as a Method To Enhance the Thermoelectric Performance of Nb-Doped Strontium Titanate Ceramics

Cited by 31 publications

References 27 publications

Review on texturization effects in thermoelectric oxides

Review on texturization effects in thermoelectric oxides

Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures

Phase Field Modelling of Abnormal Grain Growth

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Abnormal Grain Growth as a Method To Enhance the Thermoelectric Performance of Nb-Doped Strontium Titanate Ceramics

Cited by 31 publications

References 27 publications

Review on texturization effects in thermoelectric oxides

Review on texturization effects in thermoelectric oxides

Enhancement of Thermoelectric Performance of Sr0.9La0.1TiO3-Based Ceramics Regulated by Nanostructures

Phase Field Modelling of Abnormal Grain Growth

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Product

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Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures