Investigation of Barrier-Layer Materials for Mg2Si/Ni Interfaces

Sakamoto, Tatsuya; Taguchi, Yutaka; Kutsuwa, T.; Ichimi, Kiyohide; Kasatani, Shinichi; Inada, Minoru

doi:10.1007/s11664-015-4022-z

Cited by 37 publications

(20 citation statements)

References 10 publications

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“…This involves identifying suitable electrode, and diffusion and interface layers. [61][62][63] The difference in TE parameters (electrical conductivity, Seebeck coefficient, and thermal conductivity) and optimum working temperature ranges for BiTe and hH is much larger than that for BiTe/PbTe and BiTe/SKD. Therefore, it requires a complex geometrical design to optimize the voltage, current, and temperature difference.…”

Section: Introductionmentioning

confidence: 99%

Bismuth Telluride/Half‐Heusler Segmented Thermoelectric Unicouple Modules Provide 12% Conversion Efficiency

Poudel

Nozariasbmarz

et al. 2020

Advanced Energy Materials

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The rapid enhancement of the thermoelectric (TE) figure‐of‐merit (zT) in the past decade has opened opportunities for developing and transitioning solid state waste heat recovery systems. Here, a segmented TE device architecture is demonstrated in conjunction with heterogeneous material integration that results in high unicouple‐level conversion efficiency of 12% under a temperature difference of 584 K. This breakthrough is the result of success in fabricating bismuth telluride/half‐Heusler segmented TE unicouple modules using a “hot‐to‐cold” fabrication technique that provides significantly reduced electrical and thermal contact resistance. Extensive analytical and finite element modeling is conducted to provide an understanding of the nature of thermal transport and contributions arising from various thermal and physical parameters. Bismuth telluride/half‐Heusler based segmented thermoelectric generators (TEGs) can provide higher practical temperature difference with optimum average zT across the whole operating range. These results will have immediate impact on the design and development of TEGs and in the general design of devices based upon heterostructures that take advantage of gradients in the figure of merit.

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Section: Introductionmentioning

confidence: 99%

Bismuth Telluride/Half‐Heusler Segmented Thermoelectric Unicouple Modules Provide 12% Conversion Efficiency

Poudel

Nozariasbmarz

et al. 2020

Advanced Energy Materials

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“…The binary Mg 2 Si has been thoroughly studied [9][10] , and contact development has shown promising results. Ni worked well as a contacting electrode with Mg 2 Si showing good adhesion, low specific contact resistance (< 10 µΩcm 2 ) and temperature stability 9,[11][12][13][14] .…”

Section: Introductionmentioning

confidence: 99%

Developing Contacting Solutions for Mg₂Si_1–xSn_x-Based Thermoelectric Generators: Cu and Ni₄₅Cu₅₅ as Potential Contacting Electrodes

Ayachi

Hernández

Pham

et al. 2019

ACS Appl. Mater. Interfaces

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Magnesium silicides can be used for thermoelectric energy conversion, as high values of figure of merit zT were obtained for n-type (1.4 at 500 °C) and p-type (0.55 at 350 °C) materials. This, however, needs to be complemented by low resistive and stable contacting to ensure long-term thermogenerator operation and minimize losses. In this study, we selected Cu and Ni 45 Cu 55 as contacting electrodes for their high electrical conductivity, similar coefficient of thermal expansion (CTE) and good adhesion to Mg 2 (Si,Sn). Both electrodes were joined to Mg 2 Si 0.3 Sn 0.7 pellets by hot pressing in a current-assisted press. Microstructural changes near the interface were analyzed using SEM/EDX analysis, and the specific electrical contact resistance r c was estimated using a travelling potential probe combined with local Seebeck scanning. Good contacting was observed with both electrode materials. Results show low r c with Cu, suitable for application, for both n-type and p-type silicides (< 10 µΩ•cm 2 ), with the occurrence of wide, highly conductive diffusion regions. Ni 45 Cu 55 joining also showed relatively low r c values (~ 30 µΩcm 2 ) for n-and p-type, but had a less inhomogeneous reaction layer. We also performed annealing experiments with Cu-joined samples at 450 °C for one week to investigate the evolution of the contact regions under working temperatures. r c values increased (up to ~ 100 µΩcm 2 ) for annealed n-type samples, but remained low (< 10 µΩcm 2 ) for p-type. Therefore, Cu is a good contacting solution for p-type Mg 2 (Si,Sn), and a potential one for n-type if the diffusion causing contact property degradation can be prevented.

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“…Furthermore, magnesium silicides are a technologically relatively advanced material class with systematic contacting studies available [18][19][20][21][22], fabrication and analysis of lab prototypes for thermoelectric modules [23][24][25][26][27][28] and companies like Alphabet Energy commercializing Mg 2 Si-based thermoelectric generators.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric performance of Li doped, p-type Mg2(Ge,Sn) and comparison with Mg2(Si,Sn)

et al. 2016

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Solid solutions with chemical formulaMg 2 (Si,Ge,Sn) are promising thermoelectric materials with very good properties for the n-type material but significantly worse for the p-type. For power generation applications good n-and p-type materials are required and it has been shown recently that Li doping can enhance the carrier concentration and improve the thermoelectric properties for p-type Mg 2 Si 1x Sn x .We have investigated the potential of p-type Mg 2 (Ge,Sn) by optimizing Mg 2 Ge 0.4 Sn 0.6 using Li as dopant. We were able to achieve high carrier concentrations (1.4 × 10 20 cm −3) and relatively high hole mobilities resulting in high power factors of 1.7 × 10 −3 W m −1 K −2 at 700 K, the highest value reported so far for this class of material. Exchanging Ge by Si allows for a systematic comparison of Mg 2 (Ge,Sn) with Mg 2 (Si,Sn) and shows that Si containing samples exhibit a lower power factor but also a lower thermal conductivity resulting in comparable thermoelectric figure-of-merit. The data is furthermore analyzed in the framework of a single parabolic band model to gain insight on the effect of composition on band structure. 2 , here is the electrical conductivity, the thermal conductivity, the Seebeck coefficient, and the absolute temperature. A large fraction of the potentially available waste heat can be found in the mid-temperature region

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Investigation of Barrier-Layer Materials for Mg2Si/Ni Interfaces

Cited by 37 publications

References 10 publications

Bismuth Telluride/Half‐Heusler Segmented Thermoelectric Unicouple Modules Provide 12% Conversion Efficiency

Bismuth Telluride/Half‐Heusler Segmented Thermoelectric Unicouple Modules Provide 12% Conversion Efficiency

Developing Contacting Solutions for Mg₂Si_1–xSn_x-Based Thermoelectric Generators: Cu and Ni₄₅Cu₅₅ as Potential Contacting Electrodes

Thermoelectric performance of Li doped, p-type Mg2(Ge,Sn) and comparison with Mg2(Si,Sn)

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Investigation of Barrier-Layer Materials for Mg2Si/Ni Interfaces

Cited by 37 publications

References 10 publications

Bismuth Telluride/Half‐Heusler Segmented Thermoelectric Unicouple Modules Provide 12% Conversion Efficiency

Bismuth Telluride/Half‐Heusler Segmented Thermoelectric Unicouple Modules Provide 12% Conversion Efficiency

Developing Contacting Solutions for Mg2Si1–xSnx-Based Thermoelectric Generators: Cu and Ni45Cu55 as Potential Contacting Electrodes

Thermoelectric performance of Li doped, p-type Mg2(Ge,Sn) and comparison with Mg2(Si,Sn)

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Developing Contacting Solutions for Mg₂Si_1–xSn_x-Based Thermoelectric Generators: Cu and Ni₄₅Cu₅₅ as Potential Contacting Electrodes