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Thermoelectric generators held great promise through energy harvesting from waste heat. Their practical application, however, is greatly constrained by poor raw material utilization and tedious processing in fabricating desired shapes. Herein, a state‐of‐the‐art process is reported for 3D printing the half‐Heusler (Nb0.88Hf0.12FeSb) thermoelectric material using laser powder bed fusion (LPBF). The multi‐dimensional intra‐ and inter‐granular defects created by this process greatly suppress thermal conductivity by providing numerous phonon scattering centers. The resulting LPBF‐fabricated half‐Heusler exhibits a high figure of merit ≈1.2 at 923 K and a single‐leg maximum efficiency of ≈3.3% at a temperature difference (ΔT) of 371 K. Hafnium oxide nanoparticles generated during LPBF effectively prevent crack propagation, ensuring competent mechanical performance and reliable thermoelectric output. The findings highlight the significant potential of LPBF in driving the next industrial revolution of highly efficient and customizable thermoelectric materials. [ABSTRACT FROM AUTHOR]

Thermoelectric power generation is an emerging renewable energy technology, while its widespread application has been limited by its constrained output capacity. The figure of merit (ZT ) of thermoelectric materials serves as a crucial metric for performance assessment. However, researchers primarily focus on increasing the numerical value of ZT , neglecting the fact that a high ZT does not directly translate into superior performance. In this study, we employed finite element simulations to analyze the temperature-dependent properties of thermoelectric materials and examined the impact of the Seebeck coefficient, electrical and thermal conductivity on output performance of thermoelectric generators (TEG) during operation. The results reveal that a high ZT does not guarantee superior output performance. Conversely, thermal property of materials exerts more influence on output capacity than electrical property. Through appropriate adjustments, the maximum output power can be increased by up to 13%, or the maximum efficiency can be enhanced by 6% even maintaining the same ZT . Furthermore, we discuss the practical scenarios during operation and demonstrate that excessive external loads or low thermal conductivity can induce significant thermal stress on the thermoelectric device. This study would provide valuable reference for future optimal utilization of TEG to achieve high output performance and stable operation. [ABSTRACT FROM AUTHOR]

Bismuth telluride-based materials are well known for their excellent thermoelectric (TE) properties within the near-room temperature range. However, the poor thermoelectric performance of their n-type counterparts has posed a major hindrance to the application of bismuth telluride-based thermoelectric generator (TEG). In this study, a dual optimization approach was implemented. Specifically, 2D ceramic nano-sized hexagonal boron nitride (h-BN) was introduced into n-type Bi 2 Te 2.7 Se 0.3 (BTS) to enhance its performance, aligning it with p-type materials. It is indicated that ceramic h-BN decoration leads to the emergence of a high density of dislocations, which boosts the phonon scattering and reduces lattice thermal conductivity significantly. Meanwhile, a high carrier mobility is maintained to ensure an improved power factor. With the addition of moderate ceramic h-BN, the composite material achieved a ZT value of 1.1 at 400 K. The geometric configuration of TEG was optimized using finite element methods to strike the optimal balance between output power (P o u t ) and efficiency (η). Based on the structure optimization results, the predicted P o u t and η increased by 48 % and 36 %, respectively. The fabricated TEG demonstrated to achieve an efficiency of 6.4 %. This work allows the evolution from bismuth telluride-based prototype to a functional TEG advanced in room-temperature heat recovery. [ABSTRACT FROM AUTHOR]

Rational design of microstructure in thermoelectric materials is conducive to improve the thermoelectric properties. Bismuth telluride alloys are easy to form texture during sintering due to the weak van der Waals bonding between the Te-Te layers. However, high content of texture will greatly deteriorate the out-of-plane electrical properties and in-plane thermal properties. Herein, the bulk sample of n-type Bi 2 Te 2.7 Se 0.3 with controllable texture degree was obtained by selective laser melting (SLM) 3D printing technology. By setting the appropriate laser power density, the epitaxial growth of some grains in the melt pool can be suppressed and controlled texturing of the material can be achieved. The printed Bi 2 Te 2.7 Se 0.3 alloy shows texture-dependent thermoelectric properties by texture control ensuring that the Bi 2 Te 2.7 Se 0.3 alloy has both high carrier mobility and strong phonon scattering, leading to a competitive ZT ∼ 1.21 at 373 K. Based on excellent thermoelectric properties, we have assembled a 127-pair thermoelectric module with a conversion efficiency of 6.2 % at a temperature difference of 213 K, and the corresponding output performance is comparable to that of state-of-art bismuth telluride thermoelectric modules. This study illustrates the potential of texture engineering based on SLM printing in developing high-performance thermoelectric materials. • Linking selective laser melting 3D printing with texture engineering to manipulate the thermoelectric properties. • Achieving texture-degree-control by 3D printing to optimize the thermoelectric performance of Bi 2 Te 2.7 Se 0.3 materials. • The texture-controlled Bi 2 Te 2.7 Se 0.3 alloy has a competitive ZT ∼1.21 at 373 K. • The assembled state-of-art bismuth telluride TE module has a high energy conversion efficiency ∼ 6.2 %. [ABSTRACT FROM AUTHOR]