Rare earth elements (REEs) play a big role in modern technologies, including electronics, magnetics, and systems that generate clean energy. A new study explores the stability of some rare earth materials—specifically, rare earth oxychlorides—which is crucial for their future applications in clean energy and advanced electronics.
Richard Riman, RCEI Affiliate and a Distinguished Professor in the Department of Materials Science and Engineering at Rutgers University, is a co-author of the study, which was recently published in The Journal of Chemical Thermodynamics. You can read the complete study here.
The study focused on three materials: NdOCl (neodymium oxychloride), YOCl (yttrium oxychloride), and TmOCl (thulium oxychloride). These materials are being investigated for future applications like chloride ion conduction, energy storage, and catalysis. But before they can be used in high-performance devices, researchers need to understand how they behave under different conditions—including extreme cold.
The authors measured the materials’ “heat capacity”—how much energy a material can absorb as it warms—at temperatures ranging from 0 Kelvin (about -460˚F) to 500 K (about 440˚F). These ultra-cold temperatures help scientists uncover subtle details about how atoms and electrons behave in the material.
The key takeaway? All three solid materials are thermodynamically stable, which means the materials are stable over a wide range of temperatures. More importantly, the measurement enables the enthalpy, entropy, and free energy of formation to be computed, which are important properties for helping to evaluate the chemical stability of the material under a wide range of temperatures and pressures, and predict when reactions with these compounds generate or absorb heat. One of the materials, TmOCl, showed a rare low-temperature “Schottky anomaly”—a blip in heat capacity—which gives clues about its electronic behavior and could be useful in designing future technology.
“This kind of work helps lay the foundation for creating a wide range of functional devices, discovering new processes for extracting REEs from rocks and minerals, and creating domestic sources of REE. Currently, we obtain 95% of our REEs from China, making the supply chain highly dependent on the political relationship between the US and China,” says Riman. Creating a domestic source will ensure a stable supply of these highly valuable materials, so manufacturers of devices using REEs can reliably manufacture and price products.
This article was written with assistance from Artificial Intelligence, was reviewed and edited by Oliver Stringham, and was reviewed and edited by Richard Riman, a co-author on the study.
