Otherwise known as Two-Dimensional, Ordered, Double Transition Metals Carbides (MXenes), the title of the actual paper, and quoting the article (link below): "A technique for fusing different elements in layers to make a uniform and stable composite with predictable properties could open up routes to faster, smaller and more efficient energy storage devices, supercapacitors and wear-resistant and tough armored materials, according to a team at Drexel University in Philadelphia, Pennsylvania, USA. Babak Anasori and his colleagues at Drexel and Linköping University, Sweden, have demonstrated how to sandwich together two-dimensional sheets of molybdenum, titanium and carbon that would otherwise not stick together."
The higher the chemical diversity and structural complexity of two-dimensional (2D) materials, the higher the likelihood they possess unique and useful properties. Herein, density functional theory (DFT) is used to predict the existence of two new families of 2D ordered, carbides (MXenes), M′2M″C2 and M′2M″2C3, where M′ and M″ are two different early transition metals. In these solids, M′ layers sandwich M″ carbide layers. By synthesizing Mo2TiC2Tx, Mo2Ti2C3MTx, and Cr2TiC2Tx (where T is a surface termination), we validated the DFT predictions. Since the Mo and Cr atoms are on the outside, they control the 2D flakes’ chemical and electrochemical properties. The latter was proven by showing quite different electrochemical behavior of Mo2TiC2Tx and Ti3C2Tx. This work further expands the family of 2D materials, offering additional choices of structures, chemistries, and ultimately useful properties.
Materials Today: Metal sandwich solution, David Bradley