Interfacial reactions in Cu/PbTe and Cu/PbSe couples

Historically, both p- and n-type PbTe show extraordinary thermoelectric figures of merit within 300–600 °C for power generation applications. A full realization of the potential of these high-performance thermoelectric materials on a device level largely depends on the electrical and thermal contacts with the metal electrodes. Chemical inertness with a slow diffusion could be an important criterion for the selection of metal electrodes. In this work, the diffusion of the total 12 potential metal electrodes in PbTe diffusion couples are focused on and sorted, suggesting the superiority of Co as an electrode for its low diffusion coefficient and interfacial contact resistivity, inertial to PbTe and compatibility in temperature for sintering. The strategy used in this work is believed to be applicable to the selection of electrodes for other thermoelectric materials.

Section: Resultsmentioning

confidence: 83%

Screening Metal Electrodes for Thermoelectric PbTe

Liu

Zhang

et al. 2023

“…Ni, Fe, Cu, and Ag are commonly available weldable metals that can be used as electrodes as a result of their high electrical/thermal conductance and excellent wettability with solders . However, there were studies reporting severe diffusion or reaction of these metals with thermoelectric materials when working at T > 300 °C. − For examples, when hot pressed at 773 K, Ni was observed to react with p-type Bi 0.4 Sb 1.6 Te 3 , resulting in the formation of NiTe 1– x Sb x , and to diffuse seriously into n-type Bi 2 Te 2.7 Se 0.3 with a formation of a tellurium-deficient region; an interphase of Ni 3 Te 2 was observed when Ni bonded directly with PbTe at 793 K within 10 min; and Cu was reported to react and diffuse rapidly at the interfaces with PbTe when aging at T of 823 K . In addition to affect thermal stability, the severe reaction at the interface can cause a noticeable increase in contact resistance, such as that observed in n-type Bi 2 Te 2.7 Se 0.3 /Ni .…”

Section: Introductionmentioning

confidence: 99%

Screening Weldable Metal Electrodes for Ag₂Se Thermoelectric Devices below 300 °C

Liu,

Zhang,

Ding

et al. 2024

Thermoelectricity has been considered as the most important solution of generating electricity, particularly from low-grade heat below 300 °C. Despite efforts in recent years on exploring alternative materials to only commercialized Bi 2 Te 3 , the practical implementation of these new materials has been hindered by inadequate investigation into device design. Given that the utilization of weldable electrodes offers advantages in technical compatibility for a large-scale assembly of thermoelectric elements into modules, a thorough investigation into the potential of weldable metal electrodes at T < 300 °C is imperative. In this work, the diffusion of 11 kinds of thermoelectric materials in common weldable metals (Ni, Fe, Cu, and Ag) was screened. Ag is sorted out as a promising weldable electrode that can directly bond to thermoelectric Ag 2 Se in this temperature range, leading to a minimization of an interfacial contact resistivity down to 11 μΩ cm 2 in a design of the Ag/Ag 2 Se/Ag structure. The conversion efficiency of ∼3% at ΔT of 95 K with an excellent stability indicates Ag 2 Se as a top alternative to n-type Bi 2 Te 3 for low-grade heat recovery.

“…Recently, the preparation process of thermoelectric modules, especially the joining process of dissimilar materials, I e., the thermoelectric material and electrode, has attracted great interest, and so far, thermoelectric materials have been successfully bonded to metallic electrodes through soldering, , annealing, , a hot-press (HP) method, , a spark plasma sintering (SPS) method, etc. Generally, the joining processes of different thermoelectric material systems show significantly different characteristics.…”

Section: Introductionmentioning

confidence: 99%

Research Progress of Interfacial Design between Thermoelectric Materials and Electrode Materials

Yang

Sheng

et al. 2023

Intensive efforts have been conducted to realize the reliable interfacial joining of thermoelectric materials and electrode materials with low interfacial contact resistance, which is an essential step to make thermoelectric materials into thermoelectric devices for industrial application. In this review, the roles of structural integrity, interdiffusion, and contact resistance in long-term reliabilities of thermoelectric modules are outlined first. Then interfacial reactions of near-room-temperature Bi2Te3-based thermoelectric materials and various electrode materials are reviewed comprehensively. We also summarized the joining behavior of the mid-temperature PbTe-based thermoelectric materials and commonly used electrode materials. Subsequently, for other thermoelectric materials systems, i.e., SiGe, CoSb3, and Mg3Sb2, previous attempts to join with some electrode materials are also recapitulated. Finally, some future prospects to further improve the joint reliability in thermoelectric device manufacturing are proposed. We believe that this review will provide guidance for preparing thermoelectric devices and optimizing thermoelectric device design.