Waste heat from industrial equipment could be converted more efficiently using a thermoelectric material that generates voltage perpendicular to heat flow.
Large amounts of energy are routinely lost as heat in industrial systems and combustion based engines, reducing overall efficiency and limiting opportunities for energy recovery. Thermoelectric technologies offer a direct way to convert this unused heat into electricity, but conventional designs rely on layered materials that introduce electrical losses and complicate manufacturing.
A research team from Tokyo University of Science has identified a new thermoelectric material, molybdenum disilicate or MoSi2, that demonstrates strong transverse thermoelectric behaviour. The findings, led by Associate Professor Ryuji Okazaki and reported in Communications Materials, highlight the material as a viable candidate for converting waste heat into electrical energy using a simplified device structure.
Instead of generating voltage along the same direction as heat flow, the material produces electricity perpendicular to the temperature gradient. This transverse response allows thermoelectric devices to be built from a single material, avoiding multiple interfaces that normally increase resistance. Through transport measurements and first principles calculations, the researchers found that MoSi2 exhibits axis dependent conduction polarity, meaning charge carriers behave differently along different crystal directions. This effect originates from its mixed dimensional electronic structure, which enables efficient transverse thermopower generation. Experiments confirmed a clear transverse voltage signal when heat was applied at an angle to the crystal axes, with performance comparable to established transverse thermoelectric materials.
Key features of the research include:
- Single material transverse thermoelectric operation
- Reduced electrical contact resistance
- Strong transverse thermopower response
- Suitability for low temperature waste heat recovery
- Potential for thin film based device designs
Ryuji Okazaki, Associate Professor at Tokyo University of Science, says, “We wanted to explore new transverse thermoelectric materials, and MoSi2 emerged as a strong candidate because of its unique electronic structure. Our results show that mixed dimensional semimetals can deliver substantial transverse thermopower.”
By enabling simpler device architectures and efficient heat to electricity conversion, the discovery positions MoSi2 as a promising platform for future thermoelectric systems aimed at industrial energy recovery and compact power generation applications.
