Faster, Cheaper Thermoelectric Materials Process Developed

Ganpati Ramanath (Rensselaer Polytechnic Institute)

Engineers and materials scientists at Rensselaer Polytechnic Institute in Troy, New York have discovered new methods to create nanomaterials for more efficient refrigerators and cooling systems with no refrigerants or moving parts. The research is described in a paper published online in the journal Nature Materials (paid subscription required), and the authors have started commercializing their discovery.

The study, led by Rensselaer’s Ganpati Ramanath (pictured left), devised a process to create materials with thermoelectric qualities — the ability to convert electricity into a range of different temperatures, from hot to cold. While thermoelectric principles have been known for two decades, refrigerators based on these principles are small and inefficient. A key reason is that materials used in current thermoelectric cooling devices are expensive and difficult to make in large quantities.

Ramanath’s team altered the composition of nanostructured thermoelectric materials with a few atoms of sulphur, by cooking the materials for a few minutes in an everyday microwave oven. They then formed the resulting powder into pea-sized pellets by applying heat and pressure with a method to preserve the material’s properties developed by the nanostructuring and cooking.

The pellets generated by Ramanath and colleagues performed better on measures of efficiency for converting heat to electricity, in both positive and negative charges. The new method for creating the pellets is also much faster, easier, and cheaper than conventional methods of making thermoelectric materials. With an ordinary microwave oven, the team was able to produce 10 to 15 grams of the new material, about enough for several pea-sized pellets.

While the Rensselaer team’s process was developed in the lab, they have already started taking it to market. Ramanath, physicist Theodorian Borca-Tasciuc, and post-doctoral researcher (and lead author of the paper) Rutvik Mehta have filed a patent for the process. They also formed a start-up company, ThermoAura Inc. in Troy, to commercialize their thermoelectric methods. Mehta serves as ThermoAura’s president.

Read more: Nanomaterial to Boost Lithium-Ion Battery Performance

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