Scientists at the University of Michigan (U-M) recently produced stunning breakthroughs in fundamental knowledge about copper selenide (Cu₂Se). This compound has exceptional thermoelectric properties, meaning it can efficiently turn heat into electricity. This breakthrough has the potential to revolutionize energy storage technology and strengthen solid-state heating and cooling applications. The findings, which were spearheaded by doctoral student Yuxuan Wang, shed light on the elusive behavior of copper ions within the inorganic polymeric material. These findings have unveiled the ions’ liquid-like mobility, even in solid state.
Copper selenide has been a source of fascination for scientists for centuries due to its ability to be used in thermoelectric devices. Even with its promise, however, modeling this material has proven difficult, mostly due to the superionic nature of copper ions. The new study brings a long-awaited quasi-static framework that explains how heat conducts in copper selenide. This pioneering book addresses a contentious and divisive debate that has persisted for over forty years.
Understanding Copper Selenide’s Unique Characteristics
Copper selenide is noted for its high thermoelectric figure of merit, which characterizes how efficiently a material can convert thermal energy into electrical energy. This unique property makes it an ideal candidate for numerous applications ranging from energy-efficient home heaters to refrigerators. The geosciences community is investigating and characterizing these materials. They’re focused on producing systems that are quieter and more effective than traditional technologies.
One of the most striking properties of copper selenide, particularly relevant for thermoelectric applications, is its low thermal conductivity. This last property is key for thermoelectric application because it enables effective heat management in energy conversion processes. It turned out that the local vibrations of copper ions are responsible for this low thermal conductivity. These vibrations take place in pyramid-shaped enclosures formed by selenium atoms.
Knowing how copper ions move around in a material like copper selenide is key. Understanding these effects will allow us to improve the material’s application in various energy technologies.
“There are so many effects entangled together like a knot, but our new method separates each individually with low computational costs.”
As the foundation of this new quasi-static framework, we achieved an important step forward in simulating superionic materials such as copper selenide. This new framework allows computations of copper ion positions for a variety of temperatures to be made with greater precision and at a reduced cost. By reducing the rich ion-ion interactions to simple models, the framework presents exciting new directions to design superior superionic materials.
New Computational Framework Enhances Modeling Accuracy
Pierre Ferdinand Poudeu, senior author of the study, highlighted the significance of this work, explaining that
Researchers need to model these interactions more accurately in order to fully realize the potential of thermoelectric materials. This skill set is vital for their independent journey into the discipline.
“This new computational framework will help simulate and design even more efficient superionic materials for a variety of energy applications, from silent fridges to solid-state batteries and devices to turn waste heat to electricity.”
The implications of these findings about copper selenide reach far beyond the ivory tower. They have real-world importance to design sustainable energy breakthroughs. This biomass could fuel new, cleaner-burning heaters that work at higher efficiencies. It’s able to design refrigerators that use less energy and are quieter than existing models.
Implications for Future Energy Technologies
Emmanouil Kioupakis, corresponding author and U-M assistant professor, offered his perspective on what drives thermal conductivity in copper selenide. He stated,
This study provides some very significant additional knowledge to the field of copper selenide. More importantly, it signals the tremendous importance of local interactions to control material properties.
“While some expected that long-range copper ion diffusion or anharmonic vibrations caused the low thermal conductivity, those factors contribute only minor effects. Instead, copper ions’ local vibrations within the pyramid-shaped spaces selenium forms around them are the primary driver of the material’s low thermal conductivity.”
This research not only enhances the understanding of copper selenide but also emphasizes the importance of local interactions in determining material properties.