3D additive manufactured thermoelectrics: breaking efficiency barriers in waste heat recovery

Thermoelectric materials enable direct conversion between heat and electricity, offering promising applications in energy harvesting and cooling. However, their widespread adoption faces challenges, including low energy conversion efficiency, mechanical rigidity, and complex fabrication processes for high-performance devices. Traditional manufacturing methods struggle to produce customized geometries, optimize material architectures, and integrate TE components into flexible or wearable systems. Addressing these limitations, 3D printing has emerged as a transformative solution, enabling precise control over material composition, structural design, and device integration. Advanced techniques such as direct ink writing, fused filament fabrication, and digital light processing allow for the fabrication of complex, high-performance TE structures with tailored properties, including graded doping, porous architectures, and stretchable configurations. These methods enhance TE performance by optimizing heat and charge transport while enabling novel applications in flexible electronics, wearable devices, and energy-efficient cooling systems. This timely review discusses the advantages and limitations of various 3D printing approaches, highlighting their impact on the properties of TE materials and device integration. Looking ahead, future research should focus on developing novel TE inks, hybrid printing strategies, and machine learning-driven design optimization to improve device efficiency and scalability further. With continued innovation, 3D printing holds immense potential to revolutionize thermoelectric technology, paving the way for next-generation energy solutions.