20 March 2025
New material can convert waste heat into electricity
A new material, high-entropy oxide, can convert waste heat into electricity more efficiently than traditional alternatives. With low thermal conductivity and high electrical conductivity, it has great potential for energy-efficient industrial applications. In her doctoral thesis, Daria Pankratova investigated how the material can be further developed and optimized for even better performance.
Thermoelectric applications rely on semiconductor materials, that can convert heat into electricity by utilizing temperature differences. When one side of the material is heated while the other remains cool, an electric voltage is generated, driving an electrical current. For optimal performance, thermoelectric materials must have low thermal conductivity and high electrical conductivity to minimize energy loss and maximize power generation.
"High-entropy oxides can lower thermal conductivity by enhancing phonon-phonon and phonon-electron scattering," says Daria Pankratova, a doctoral student in experimental physics at Luleå University of Technology.
High-entropy oxides (HEOs) are a new class of ceramic materials with complex chemical compositions. By combining multiple metals within the same crystal structure, these materials gain unique properties that enhance their stability, electrical conductivity, and thermal behavior.
By testing different chemical compositions—including cobalt, chromium, iron, manganese, nickel, and copper—Pankratova identified the most promising materials. The oxides were synthesized using Spark Plasma Sintering and Solid-State Reaction. Some compositions resulted in a single-phase crystal structure, improving electrical conductivity.
"Single-phase materials exhibited higher electrical conductivity, likely due to reduced electron-phonon scattering," Pankratova explains.
Replacing nickel with copper made it easier to achieve a single-phase structure. Additionally, these materials allow for the production of both p-type and n-type semiconductors, essential for thermoelectric modules.
"This could lead to more efficient thermoelectric materials for industrial and energy-efficient applications," says Pankratova.
The study highlights the potential of high-entropy oxides to enhance thermoelectric devices by reducing heat conductivity while maintaining good electrical properties. The findings could contribute to a more sustainable energy future by converting waste heat into electricity.
Contact
Daria Pankratova
- Doctoral student
- 0920-49
- daria.pankratova@associated.ltu.se
- Daria Pankratova
Published:
Updated: