Applications of thermodynamic calculations to practical TEG design: Mg2(Si0.3Sn0.7)/Cu interconnections

Ayachi, Sahar; Fries, Suzana G.; Müller, Eckhard; Boor, Johannes de

doi:10.1039/d1ta05289f

Cited by 6 publications

(2 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Cu/Mg 2 Sn 0.75 Ge 0.25 interface exhibited excellent initial performance (𝜌 c < 1 μΩ cm 2 , 𝜎 s > 15 MPa), but it suffered from stability issues during long-term operation. [45,48,61] Therefore, Cu was selected as the matrix element for this study. The principles of high bonding propensity, CTE matching, diffusion passivation, and dopant inactivation [9,53] were employed for further optimization of the target multi-element TEiM.…”

Section: Design Of the Teimmentioning

confidence: 99%

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg₂Sn_0.75Ge_0.25‐Based Thermoelectric Devices

Lin

Liu

et al. 2023

Advanced Energy Materials

View full text Add to dashboard Cite

Electrode contact interfaces for practical thermoelectric (TE) devices require high bonding strength, low specific contact resistivity, and superb stability. Herein, the state‐of‐the‐art Cu2MgFe/Mg2Sn0.75Ge0.25 interface is designed for Mg2Sn0.75Ge0.25‐based TE devices, adhering to the general strategy of high bonding propensity, thermal expansion matching, diffusion passivation, and dopant inactivation. The interfacial stability is verified by the in situ transmission electron microscopy analysis, thereby confirming the contributions from decreasing the chemical potential gradient and increasing the diffusion activation energy barrier. The single‐leg device exhibits a high power density (ωmax) of 2.6 W cm−2 and conversion efficiency (ηmax) of 8% under a temperature difference (ΔT) of 370 °C, which is the record‐breaking value in comparison to other Mg2(Si, Ge, Sn)‐based TE devices. Additionally, a two‐couple device with p‐type Bi2Te3 shows an excellent ωmax of 1.3 W cm−2 and ηmax of 5.4% under a ΔT of 270 °C, comparable to commercial Bi2Te3 devices. The proposed interface design strategy provides a general technique for constructing high‐performance devices using cutting‐edge TE materials.

show abstract

Section: Design Of the Teimmentioning

confidence: 99%

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg₂Sn_0.75Ge_0.25‐Based Thermoelectric Devices

Lin

Liu

et al. 2023

Advanced Energy Materials

View full text Add to dashboard Cite

show abstract

“…Thus, it is crucial to reach a sufficiently high carrier concentration in order to optimize p-type Mg 2 (Si, Sn) and be able to build high-performing TEG based on magnesium silicide. This is desirable as employing the same material class for both n-and p-type could reduce the considerable chemical complexity in the contact development [10] and avoid mismatch of the coefficient of thermal expansion between the p-and n-type legs in TEG [11], thus making p-type Mg 2 (Si,Sn) a promising candidate for pairing with n-type Mg 2 (Si,Sn) for TEG application [12].…”

Section: Introductionmentioning

confidence: 99%

Understanding the dopability of p-type Mg₂(Si,Sn) by relating hybrid-density functional calculation results to experimental data

Kamila¹,

Ryu²,

Ayachi³

et al. 2022

J. Phys. Energy

Self Cite

View full text Add to dashboard Cite

Reaching a sufficiently high carrier concentration is crucial for thermoelectric material optimization in developing Mg2X (X = Si, Ge, and Sn)-based thermoelectric generators (TEGs). While n-type Mg2(Si,Sn) has excellent thermoelectric properties, p-type shows suboptimal thermoelectric performance because of insufficient carrier concentration, in particular for Mg2Si and Si-rich Mg2(Si,Sn). A systematic investigation of Li-doped Mg2Si1-xSnx has been performed as Li, in contrast to other typical dopants, has a high solubility in the material system and has been shown to yield the highest reported carrier concentrations. We observe that the carrier concentration increases with Li content, but the dopant efficiency decreases. With respect to the Si:Sn ratio, we find a clear increase in maximum achievable carrier concentration and dopant efficiency with increasing Sn content. The trends can be understood employing defect formation energies obtained within the hybrid-density functional theory (DFT) for the binaries. We furthermore use a linear interpolation of the hybrid-DFT results from the binaries to the ternary Mg2(Si,Sn) compositions and a simple single parabolic band model to predict the maximal achievable carrier concentration for the solid solutions, providing a simple guideline for experimental work. Finally, we show that the approach is transferable to other material classes. This work highlights that besides dopant solubility the interplay between intrinsic and extrinsic defects determines the achievable carrier concentration.

show abstract

High‐Performance Thermoelectric Devices Made Faster: Interface Design from First Principles Calculations

Ayachi,

Park,

Ryu

et al. 2023

Advanced Physics Research

Self Cite

View full text Add to dashboard Cite

The enormous progress achieved with high‐performance thermoelectric materials has yet to be implemented in high‐performance devices. The bottleneck for this is the material‐specific design of the interface between the thermoelectric material and the electrical connections, particularly identifying suitable contacting electrodes. This has mainly been empirical, slowing down device maturation due to the vast experimental space. To overcome this, an electrode pre‐selection method based on first‐principles electronic structure calculations of charged defect formation energies is established in this work for the first time. Such method allows to predict thermoelectric leg degradation due to impurity diffusion from the electrode into the thermoelectric material and formation of charge carrier traps, causing a majority carrier compensation and performance deterioration. To demonstrate the feasibility of this approach, the charged point defect formation energies of relevant metal electrodes with Mg2(Si,Sn) are calculated. Five hundred ten defect configurations are investigated, and the interplay between intentional doping and electrode‐induced point defects is predicted. These predictions are compared with Seebeck microprobe measurements of local carrier concentrations near the Mg2(Si,Sn)‐electrode interface and a good match is obtained. This confirms the feasibility of electrode screening based on defect formation energy calculations, which narrows down the number of potential electrodes and accelerates device development.

show abstract

Applications of thermodynamic calculations to practical TEG design: Mg₂(Si_0.3Sn_0.7)/Cu interconnections

Abstract: Magnesium silicide stannide solid solutions, Mg2(Si,Sn), are prominent materials in the development of devices for thermoelectric energy conversion for intermediate operation temperatures, owing to high values of the thermoelectric figure...

Cited by 6 publications

References 36 publications

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg₂Sn_0.75Ge_0.25‐Based Thermoelectric Devices

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg₂Sn_0.75Ge_0.25‐Based Thermoelectric Devices

Understanding the dopability of p-type Mg₂(Si,Sn) by relating hybrid-density functional calculation results to experimental data

High‐Performance Thermoelectric Devices Made Faster: Interface Design from First Principles Calculations

Contact Info

Product

Resources

About

Applications of thermodynamic calculations to practical TEG design: Mg2(Si0.3Sn0.7)/Cu interconnections

Abstract: Magnesium silicide stannide solid solutions, Mg2(Si,Sn), are prominent materials in the development of devices for thermoelectric energy conversion for intermediate operation temperatures, owing to high values of the thermoelectric figure...

Cited by 6 publications

References 36 publications

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg2Sn0.75Ge0.25‐Based Thermoelectric Devices

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg2Sn0.75Ge0.25‐Based Thermoelectric Devices

Understanding the dopability of p-type Mg2(Si,Sn) by relating hybrid-density functional calculation results to experimental data

High‐Performance Thermoelectric Devices Made Faster: Interface Design from First Principles Calculations

Contact Info

Product

Resources

About

Applications of thermodynamic calculations to practical TEG design: Mg₂(Si_0.3Sn_0.7)/Cu interconnections

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg₂Sn_0.75Ge_0.25‐Based Thermoelectric Devices

Interface Engineering Boosting High Power Density and Conversion Efficiency in Mg₂Sn_0.75Ge_0.25‐Based Thermoelectric Devices

Understanding the dopability of p-type Mg₂(Si,Sn) by relating hybrid-density functional calculation results to experimental data