Croissants get their signature flaky texture through a process called lamination where alternating layers of dough and butter rise in the oven to create the perfect bite. Likewise, MXenes are special materials made up of ultrathin layers of transition metals and carbon atoms.
Their hallmark stratified structures make them remarkable heat and electricity conductors, while also giving them strength and durability—properties that make them highly prized in electronic, technology and energy industries.
However, much of how MXenes’ atomic structures influence their properties have remained elusive. Until a few years ago, most MXenes were composed of just one or two metals. Now, experts say tremendous leaps in the field have enabled researchers to double the number of metallic building blocks, significantly expanding both the complexity and potential of these so-called high-entropy (HE) MXenes.
“Designing HE MXenes with certain properties is often a process of experimentation and intuition, especially with the complexity introduced by four metals, making navigating the design space challenging,” said Teck Leong Tan, a Senior Scientist and the Director of the Materials Science & Chemistry Department at A*STAR’s Institute of High Performance Computing (IHPC).
On a mission to unravel the intricacies of HE MXenes, Tan and his team from IHPC collaborated with researchers from Purdue University, using advanced computer simulations to help model how atoms are distributed over the layers. The researchers studied two new HE MXenes (TiVNbMoC3 and TiVCrMoC3) with surprising results.
A simulation of the outer and inner atomic layers of the high-entropy MXene TiVNbMoC3 at a relatively low temperature (464 K). Mo and Ti show strong preferences towards outer and inner layers respectively; V and Nb show similar preferences but to a lesser extent.
©️ A*STAR Research
Contrary to previous assumptions that the elements are randomly distributed, the simulations revealed a preference for Cr to position itself on the material’s surface, followed in order by Mo, V, Nb and Ti. Even when the MXenes are heated to high temperatures, they retain this atomic arrangement.
“The precise arrangement of metals can vary based on their composition, allowing us to fine-tune these MXenes for targeted applications,” said Tan, who added that these and future studies can help expand the future application landscape of MXenes.
Not stopping here, the research team has plans to collaborate with other materials scientists to validate their simulated predictions on HE MXenes’ structure. They also aim to formulate reliable models to simulate and study more of HE MXenes’ unique structures.
The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing (IHPC).
