Demonstration of a robust, tellurium-free thermoelectric module for near-room-temperature applications with a high conversion efficiency of 8.5% and a maximum cooling of 72 K. 

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A robust thermoelectric module based on MgAgSb/Mg<sub>3</sub>(Sb,Bi)<sub>2</sub>with a conversion efficiency of 8.5% and a maximum cooling of 72 K

Miniaturized in-plane π-type thermoelectric device composed of a II–IV semiconductor thin film prepared by microfabrication

A huge concern regarding global warming, as well as the depletion of natural fuel resources, has led to a wide search for alternative energy sources. Due to their high reliability and long operation time, thermoelectric generators are of significant interest for waste heat recovery and power generation. The main disadvantage of TEGs is the low efficiency of thermoelectric commercial modules. In this work, a unique design for a multilayer TE unicouple is suggested for an operating temperature range of 50–600 °C. Two types of thermoelectric materials were selected: «low temperature» n-and p-type TE materials (for the operating temperature range of 50–300 °C) based on Bi2Te3 compounds and «middle temperature» (for the operating temperature range of 300–600 °C) n- and p-type TE materials based on the PbTe compound. The hot extrusion technology was applied to fabricate n- and p-type low-temperature TE materials. A unique design of multilayer TEG was experienced to achieve an efficiency of up to 15%. This allows for the possibility of extracting this amount of electrical power from the heat generated for domestic and water heating. 

https://www.mdpi.com/1996-1073/15/11/3960/pdf?version=1653645347

Development of a High Perfomance Gas Thermoelectric Generator (TEG) with Possibible Use of Waste Heat

Thermoelectric power generation from the prototype π-shaped module composed of p-type colusite (Cu26Cr2Ge6S32) and n-type nanostructured PbTe (Pb0.98Ga0.02Te-3% GeTe) was demonstrated in this study. The thermoelectric figure of merit zT of Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe was ∼0.8 and ∼1.2 at 665 K, respectively. In PbTe, transmission electron microscopic images and energy-dispersive x-ray elemental maps reveal the insertion of nanoscale precipitates induced by the GeTe alloying. Contact layers based on Au and Co-Fe were used for p- and n-type thermoelectric legs, respectively, which allow the low electrical specific contact resistances of ≤10 × 10−10 Ω m2 at room temperature. Maximum thermoelectric conversion efficiency ηmax of ∼5.5% was obtained for the Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe-based two-pair module when the hot-side Th and cold-side Tc temperatures were maintained at 673 and 283 K, respectively. A three-dimensional finite-element simulation predicts the ηmax of ∼7.1% for the module at Th and Tc of 673 and 283 K, respectively. 

A prototype thermoelectric module based on p-type colusite together with n-type nanostructured PbTe for power generation

Ni substitution improves the high-temperature thermoelectric performance of electronegative element Se-filled skutterudite Se0.05Ni Co4-Sb12

Thermoelectric generators (TEGs) offer a versatile solution to convert low-grade heat into useful electrical power. While reducing the length of the active thermoelectric legs provides an efficient strategy to increase the maximum output power density pmax, both the high electrical contact resistances and thermomechanical stresses are two central issues that have so far prevented a strong reduction in the volume of thermoelectric materials integrated. Here, it is demonstrated that these barriers can be lifted by using a nonconventional architecture of the legs which involves inserting thick metallic layers. Using skutterudites as a proof-of-principle, several single-couple and multi-couple TEGs with skutterudite layers of only 1 mm are fabricated, yielding record pmax ranging from 3.4 up to 7.6 W cm−2 under temperature differences varying between 450 and 630 K. The highest pmax achieved corresponds to a 60-fold increase per unit volume of skutterudites compared to 1 cm long legs. This work establishes thick metallic layers as a robust strategy through which high power density TEGs may be developed.

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High Power Density Thermoelectric Generators with Skutterudites

The invention relates to a thermoelectric element, which is especially for a thermoelectric converter, including an assembly of constituent layers comprising a central layer made of p- or n-type thermoelectric material, then, in an assembly direction, and on each side of said central layer, an intermediate layer forming a diffusion barrier followed by a buffer layer made of composite metal material, said buffer layers being intended to be securely fastened to metal electrodes, characterised in that the cumulative thickness of the two buffer layers is larger than or equal to 50% of the thickness of the central layer, and preferably larger than or equal to 100% of the thickness of the central layer and very preferably larger than or equal to 200% of the thickness of the central layer, and in that the constituent material of the buffer layers is an alloy of two metals chosen from the family: Tix Ag1-x, Vx Fe1-x, Vx Ag1-x, Tix Fe1-x, where 0 < x < 1.

Eugen Geczi

Papers

High Power Density Thermoelectric Generators with Skutterudites

Improved thermoelectric element and thermoelectric converter including at least one such element

Element thermoelectrique ameliore et convertisseur thermoelectrique comportant un tel element.