New ink-based method offers best-ever recipe for thermoelectric devices

Power plants, factories, car engines—anything that consumes energy produces heat, much of which is wasted. Thermoelectric devices could capture this wasted heat and convert it to electricity, but they are prohibitively expensive and complicated to produce.

Yanliang Zhang, professor of aerospace and mechanical engineering in the Department of Advanced Materials and Manufacturing at the University of Notre Dame, and his colleagues in a multi-institutional team have developed an ink-based manufacturing method that enables the economic and mass production of high-performance thermoelectric devices.

The results of their research were recently published in Energy and Environmental Science.

“With our novel formulation and ink processing technique, we’ve produced a material that’s more efficient at converting waste heat into energy than any previous ink-based device,” Zhang said. “With this method, we can produce devices in a wide range of sizes—a film a few microns thick, or a device large enough to harvest waste heat from a power plant.”

To convert heat into electricity, thermoelectric devices require a hot side and a cold side. Electricity must flow freely through the material, but heat must not, because that would eliminate the temperature gradient necessary for the device to operate efficiently.

Zhang explained that materials with these unique properties were previously produced using labor- and energy-intensive processes that lacked uniformity and scalability.

The team’s ink “recipe” combines thermoelectric particles with a solvent and tellurium, an additive that reduces defects in the material and helps densify and harden the resulting composite. The team’s ink-based manufacturing technique also gave them more control over the material’s microstructure and final 3D geometry than previous methods.

Thermoelectric devices can also be used for cooling without emissions and without refrigerant if an electrical power supply is provided.

“We believe that our findings are very promising for recovering waste heat, improving energy efficiency and reducing CO₂ “Emission reduction and environmentally friendly solid-state refrigeration and freezing,” Zhang said.