Tellurium-free thermoelectric materials and modules for room temperature cooling

• Applicant: Dr. Pingjun Ying
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563885086

Thermoelectric cooling technology holds significant promise due to its solid-state nature, but its application potential has been largely confined to bismuth telluride (Bi2Te3). Unfortunately, Bi2Te3-based technology faces critical limitations hindering its scalability for future thermoelectric applications. Firstly, tellurium, a toxic and scarce element in nature, is a key component, posing environmental and resource challenges. Secondly, the cooling performance has stagnated for over half a century, making further advancements unlikely. Recent years have seen noteworthy progress in thermoelectric materials. However, the translation of these high-performing materials into effective modules has been limited. Furthermore, existing module investigations primarily focus on power generation, neglecting the immense potential for cooling applications. In a recent breakthrough, the Principal Investigator (PI) demonstrated that Mg-based materials, including n-type Mg3(Sb,Bi)2 and p-type MgAgSb, yielded a cooling module with performance on par with Bi2Te3. Based on this achievement, our project aims to surpass current cooling performance standards in thermoelectric modules. This ambitious goal necessitates three main research focuses: enhancing material performance, implementing an advanced contact design with minimal resistance, and optimizing geometric factors at the module level. To improve material properties, we will employ a segmentation strategy, particularly focusing on the n-type leg, and fine-tune the microstructure for further improvement. Simultaneously, our investigation of the contact side will concentrate on exploring materials and methodologies that facilitate high bonding strength, low contact resistance, and diffusion passivation. This approach aims to optimize the performance of Mg-based thermoelectric modules. Once optimized material performance and successful contact design have been achieved, our project will investigate the influence of various thermoelectric geometries on cooling efficiency. This investigation will consider parameters such as the filling factor and the ratio of length to cross-sectional area to maximize the cooling performance of our Mg-based modules. The success of this project promises a breakthrough in sustainable, reliable, and non-toxic thermoelectric technology. Furthermore, it addresses critical technical questions, paving the way for the scalable implementation of this technology.

• DFG Programme: Research Grants