Conduction type control and power factor enhancement of the thermoelectric material Al2Fe3Si3

Takagiwa, Yoshiki; Isoda, Yukihiro; Goto, Masahiro; Shinohara, Yoshikazu

doi:10.1016/j.jpcs.2018.03.003

Cited by 18 publications

(38 citation statements)

References 19 publications

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“…As shown in the inset of Figure 8(d), the temperature dependence of κ ph from 150 K to 300 K was proportional to 1/T, which suggested that Umklapp scattering played the main role in the decrease of κ ph . One can compare the thermoelectric properties of t-FeAl 2 with those of other intermetallic thermoelectrics, Fe 2 VAl [38][39][40][41][42] and Al 2 Fe 3 Si 3 [43][44][45][46]. The κ ph of t-FeAl 2 was several times larger than that of Al 2 Fe 3 Si 3 .…”

Section: Thermoelectric Properties Of Fealmentioning

confidence: 99%

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl₂

Tobita

Kitahara

Katsura

et al. 2019

Science and Technology of Advanced Materials

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Tetragonal FeAl 2 is a high-pressure phase and is predicted to exhibit semiconductor-like behavior. We investigated the pressure and temperature synthesizing conditions of tetragonal FeAl 2 , supported by in situ X-ray diffractions, using synchrotron radiation during heating the sample under a pressure of 20 GPa. Based on the determined optimal conditions, we synthesized the bulk polycrystalline samples of tetragonal FeAl 2 at 7.5 GPa and 873 K, using a multi-anvil press and measured its thermoelectric properties. The Seebeck coefficient of tetragonal FeAl 2 showed a large negative value of -105 μV/K at 155 K and rapidly changed to a positive value of 75 μV/K at 400 K. Although these values are the largest among those of Fe-Al alloys, the maximum power factor remained at 0.41 mW/mK 2 because the carrier concentration was not tuned. A comparison of the Gibbs free energy of tetragonal FeAl 2 , triclinic FeAl 2 and FeAl+Fe 2 Al 5 revealed that tetragonal FeAl 2 became unstable as the temperature increased, because of its smaller contribution of vibrational entropy.Temperature, T / K Pressure, P / GPa ARTICLE HISTORY

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Section: Thermoelectric Properties Of Fealmentioning

confidence: 99%

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl₂

Tobita

Kitahara

Katsura

et al. 2019

Science and Technology of Advanced Materials

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“…13 We reported that the Fe 3 Al 2 Si 3 phase would be suited for thermoelectric materials because they form a narrow band gap near the Fermi level, 8 and the Al/Si ratio could tune the conduction type of n-and p-type for Fe 3 Al 2 Si 3 alloys. 10 Shiota et al reported the thermoelectric properties of Fe 3 Al 2 Si 3 materials and the effects of Co-and Mn-substitutions for Fe on the thermoelectric properties to obtain n-and p-type materials. 9,11 We succeeded in enhancing the power factor (∼40%) at mid-temperatures for n-type Fe 3 Al 2 Si 3 thermoelectric materials using a machine-learning method.…”

Section: Introductionmentioning

confidence: 99%

Earth-Abundant Fe–Al–Si Thermoelectric (FAST) Materials: from Fundamental Materials Research to Module Development

Takagiwa

Ikeda

Kojima

2020

ACS Appl. Mater. Interfaces

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To develop an autonomous power generation technology to support an internet-of-things (IoT) society, we proposed low-cost and nontoxic Fe−Al−Si-based thermoelectric (FAST) materials consisting of an Fe 3 Al 2 Si 3 phase. Because of the cost-effectiveness and easy disposal of FAST materials, they are attractive for autonomous power supplies to drive IoT sensors and devices. While bismuth−tellurium-based thermoelectric power generation modules have been commercialized, the discovery of FAST materials opens an additional route to generate power from waste heat at room temperature under a small temperature difference, which will expand the diversity of applications of thermoelectric power generation modules. This paper reports the thermoelectric properties of FAST materials synthesized by conventional laboratory-scale synthesis and mass production processes, enhancement of power factor less than 600 K through homogenization and removal of metallic precipitations, development of thermoelectric power generation modules, and the results of power generation tests. The operation of temperature/humidity sensors and wireless transmission by Bluetooth low energy communication using FAST materials-based modules under a small temperature difference at room temperature was demonstrated.

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“…The maximum PF of ∼750 μW m −1 K −2 was achieved at 473 K for the sample with x = 4.0, which is the highest among n-type FAST materials. 8,17,18,21,24,27 Compared with undoped FAST samples (Figure S5), the heavily Co-doped samples (x > 3) exhibited much larger σ but lower S because of higher carrier concentration (n) for heavily Co-doped samples increased. However, Co-doped samples did not show a monotonic change in σ with increasing Co content (Figure S2), which may be brought by a decrease in the carrier mobility because of an increase in carrier scattering for higher Co-doped samples.…”

Section: Dopant Concentration Optimizationmentioning

confidence: 99%

“…The calculated absolute values of S at room temperature were greater than 100 μV K −1 for both p-and n-type FAST materials; subsequent experiments confirmed these values. 8,17,21 Note that the TE properties of FAST materials depend on the conditions of the synthesis process, such as the cooling rate from the melt and the annealing conditions, because the τ 1 -phase is produced by a peritectic reaction. The present mass production method (∼kg/batch) of FAST materials combines a powder synthesis process (induction heating and gas atomization methods) and a bulk synthesis process (spark plasma sintering method).…”

Section: Overview Of Fe−al−si Thermoelectric (Fast) Materialsmentioning

confidence: 99%

Fe–Al–Si Thermoelectric (FAST) Materials and Modules: Diffusion Couple and Machine-Learning-Assisted Materials Development

Takagiwa

Hou

Tsuda

et al. 2021

ACS Appl. Mater. Interfaces

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To lower the introduction and maintenance costs of autonomous power supplies for driving Internet-of-things (IoT) devices, we have developed low-cost Fe−Al−Si-based thermoelectric (FAST) materials and power generation modules. Our development approach combines computational science, experiments, mapping measurements, and machine learning (ML). FAST materials have a good balance of mechanical properties and excellent chemical stability, superior to that of conventional Bi− Te-based materials. However, it remains challenging to enhance the power factor (PF) and lower the thermal conductivity of FAST materials to develop reliable power generation devices. This forum paper describes the current status of materials development based on experiments and ML with limited data, together with power generation module fabrication related to FAST materials with a view to commercialization. Combining bulk combinatorial methods with diffusion couple and mapping measurements could accelerate the search to enhance PF for FAST materials. We report that ML prediction is a powerful tool for finding unexpected off-stoichiometric compositions of the Fe−Al−Si system and dopant concentrations of a fourth element to enhance the PF, i.e., Co substitution for Fe atoms in FAST materials.

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Conduction type control and power factor enhancement of the thermoelectric material Al2Fe3Si3

Cited by 18 publications

References 19 publications

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl₂

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl₂

Earth-Abundant Fe–Al–Si Thermoelectric (FAST) Materials: from Fundamental Materials Research to Module Development

Fe–Al–Si Thermoelectric (FAST) Materials and Modules: Diffusion Couple and Machine-Learning-Assisted Materials Development

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Conduction type control and power factor enhancement of the thermoelectric material Al2Fe3Si3

Cited by 18 publications

References 19 publications

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl2

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl2

Earth-Abundant Fe–Al–Si Thermoelectric (FAST) Materials: from Fundamental Materials Research to Module Development

Fe–Al–Si Thermoelectric (FAST) Materials and Modules: Diffusion Couple and Machine-Learning-Assisted Materials Development

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Product

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Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl₂

Phase stability and thermoelectric properties of semiconductor-like tetragonal FeAl₂