A thermoelectric material has been developed for green energy solutions.

Industrial waste heat generated during production is a significant source of energy that is typically lost to the environment. To enhance energy efficiency, technologies have been developed that allow for the capture and conversion of heat into electricity. Thermoelectric materials can assist in this process, which are classified by temperature ranges: low-temperature (up to 575 K), mid-temperature (575–925 K), and high-temperature (above 925 K). While the first two types are well-studied, the latter still requires in-depth research.

Materials based on calcium manganese perovskite with the addition of maricite exhibit improved thermoelectric properties at elevated temperatures, surpassing known analogs. These characteristics are achieved through controlled porosity (10–22 percent) and an optimized structure, which significantly influences heat and electrical conductivity.

“The material must not only possess high thermal stability but also be economically viable and environmentally safe. Oxide thermoelectrics best meet these criteria. They can function as either electron or hole conductors, enabling the creation of efficient thermoelectric modules by combining materials with different types of conductivity to enhance device performance,” explained project leader, PhD Sergey Yudin, a leading expert at the Research Center for Structural Ceramic Nanomaterials at NITU MISIS.

Researchers from NITU MISIS proposed a method that includes molecular mixing of chemical substances, where ions are evenly distributed in the solution, creating a foundation for a homogeneous material. The liquid is then transformed into an aerosol, with droplets entering the hot zone of the reactor. There, local combustion occurs, allowing precise control over composition and the formation of unique microstructures, such as hollow or porous spheres with specified wall thickness and pore size, without intermediate processing stages.

The resulting powder is compacted and sintered at high temperatures. New phases form within its structure, enhancing properties crucial for the thermoelectric efficiency of the material. Details of the research have been published in the Journal of the European Ceramic Society (Q1).

“The new method allows for precise tuning of the material's morphology and composition. The difference from analogs lies in achieving record efficiency in converting heat to electricity for pure calcium manganese perovskite, thanks to a unique combination of porosity, phase composition, and uniformity of structure. Additionally, the method eliminates the lengthy high-temperature sintering used in traditional approaches, making it more energy-efficient and easier to scale,” explained Zhanna Ermekova, PhD, a researcher at the Research Center for Structural Ceramic Nanomaterials at NITU MISIS.

In the future, researchers plan to focus on finding optimal concentrations as well as studying various additives and their effects on the thermoelectric properties of the material. This data will help develop more efficient and stable composites for high-temperature applications.

The work was carried out with financial support from the Russian Science Foundation.