A new method for synthesising MXenes

The journal “Nature Synthesis” has published a paper presenting a new method for obtaining MXenes – advanced two-dimensional materials with great potential for use in electronics and energy. Among the co-authors of the publication is Dr Kamil Sobczak, head of the Laboratory of Microscopy and Electron Spectroscopy at the UW’s Biological and Chemical Research Centre.

The article Triphasic synthesis of MXenes with uniform and controlled halogen terminations presents an innovative three-phase method of MXene synthesis (gas-liquid-solid, GLS).

Dr Kamil Sobczak from the Laboratory of Microscopy and Electron Spectroscopy at the UW’s Biological and Chemical Research Centre participated in the research, where he was responsible for the advanced structural characterisation of new MXenes using transmission electron microscopy (TEM).

MXenes are two-dimensional materials from the family of transition metal carbides and nitrides, which are distinguished by their very good electrical conductivity and are used, among others, in (opto)electronics, energy storage, electromagnetic wave shielding and terahertz detectors.

A key role in determining the properties of MXenes is played by so-called terminations – functional groups located on their surface. However, previous synthesis methods led to the formation of materials with mixed and randomly distributed terminations, which resulted in disordered surface structures and impaired charge transport.

Better properties

As researchers emphasise, the new strategy represents a significant breakthrough. The GLS method enables the production of MXenes with uniform and precisely controlled halogen terminations (Cl, Br, I and their combinations). The process is highly efficient – from 81 to 85% for Ti₃C₂Cl₂, Ti₃C₂Br₂ and Ti₃C₂I₂ materials – while maintaining high structural integrity. It also allows for the synthesis of MXenes with mixed dual- and triple-halogen terminations.

The resulting materials show a significant improvement in transport properties. Compared to conventional MXenes with mixed Cl/O terminations, a more than 160-fold increase in macroscopic electrical conductivity and a 13-fold increase in terahertz conductivity were observed.

The authors of the publication emphasise that the developed method opens up new possibilities for designing MXenes with tailor-made properties, which are key for future electronic, optoelectronic, catalysis and energy storage technologies.