Thermodynamic principles governing MXene formation by molten salt etching
4 affiliations
- 1Materials Design Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, 581 83 Linköping, Sweden
- 2Wallenberg Initiative Materials Science for Sustainability (WISE), IFM, Linköping University, 581 83 Linköping, Sweden
- 3Department of Biomedical Engineering, College of Biomedicine, City University of Hong Kong, Hong Kong SAR, China
- 4Layered Materials Editing Center, Yongjiang Laboratory, Ningbo 315202, China
Abstract
Controlled reactions between MAX phases and molten salts allow selective A-element substitution or full A-element removal, providing a versatile route to both new MAX phases and two-dimensional (2D) MXenes. Despite its success, the broader applicability of this strategy remains limited, and the predictive power of theoretical approaches has not been systematically established. We recently introduced a thermodynamic methodology based on process-specific phase diagrams to describe reactions of MAX phases in molten salts, demonstrated for a narrowly defined set of representative systems. Here, we generalize this framework by adopting a more inclusive description of competing reaction outcomes and assess its applicability across a broad chemical space comprising 14 MAX phases and 7 molten salts. The predictions are benchmarked against reported experimental data and complemented by new experiments on previously unexplored MAX–salt combinations, encompassing both MXene synthesis and reaction outcomes beyond A-element substitution and MXene formation. While idealized stoichiometric models capture many trends, we identify experimentally relevant cases where non-ideal features – particularly non-stoichiometric A-element substitution and reduced termination occupancy – are required for quantitative agreement. More broadly, analysis of thermodynamic trends across all MAX–salt combinations yields clear criteria under which MXene formation is highly likely. The resulting framework provides a validated basis for computational screening and is expected to guide molten-salt-driven exfoliation strategies toward new two-dimensional materials beyond the MXene family.
Related
- A grand potential for molten-salt electrochemical phase diagrams from first principles
- Operating conditions redefine the governing principles of catalyst-layer fabrication
- First-principles investigation of hydrogen storage capacity, electronic, optical, mechanical, and thermodynamic properties of alkaline-metal-based K₂LiXH₆ (X = Mg, Ca) hydrides.
- High-Throughput Combinatorial Screening of Refractory Amorphous Alloys for Fusion Capillary Systems via a Calibrated First-Principles Continuum-Thermodynamic Model
- Thermodynamic and Mechanistic Aspects of Small-Ring Formation Mediated by Nonheme-Iron and 2‑Oxoglutarate Dependent Enzymes.
BibTeX
@article{bjork2026thermodynamic,
title = {{Thermodynamic principles governing MXene formation by molten salt etching}},
author = {Jonas Björk and Haoming Ding and Qing Huang and Johanna Rosén},
journal = {Materials Today},
year = {2026},
month = jul,
doi = {10.1016/j.mattod.2026.103457},
url = {https://doi.org/10.1016/j.mattod.2026.103457},
note = {CC BY},
}
RIS
TY - JOUR
TI - Thermodynamic principles governing MXene formation by molten salt etching
AU - Jonas Björk
AU - Haoming Ding
AU - Qing Huang
AU - Johanna Rosén
PY - 2026
DA - 2026/07/28
JO - Materials Today
DO - 10.1016/j.mattod.2026.103457
UR - https://doi.org/10.1016/j.mattod.2026.103457
AB - Controlled reactions between MAX phases and molten salts allow selective A-element substitution or full A-element removal, providing a versatile route to both new MAX phases and two-dimensional (2D) MXenes. Despite its success, the broader applicability of this strategy remains limited, and the predictive power of theoretical approaches has not been systematically established. We recently introduced a thermodynamic methodology based on process-specific phase diagrams to describe reactions of MAX phases in molten salts, demonstrated for a narrowly defined set of representative systems. Here, we generalize this framework by adopting a more inclusive description of competing reaction outcomes and assess its applicability across a broad chemical space comprising 14 MAX phases and 7 molten salts. The predictions are benchmarked against reported experimental data and complemented by new experiments on previously unexplored MAX–salt combinations, encompassing both MXene synthesis and reaction outcomes beyond A-element substitution and MXene formation. While idealized stoichiometric models capture many trends, we identify experimentally relevant cases where non-ideal features – particularly non-stoichiometric A-element substitution and reduced termination occupancy – are required for quantitative agreement. More broadly, analysis of thermodynamic trends across all MAX–salt combinations yields clear criteria under which MXene formation is highly likely. The resulting framework provides a validated basis for computational screening and is expected to guide molten-salt-driven exfoliation strategies toward new two-dimensional materials beyond the MXene family.
SN - 1369-7021
SN - 1873-4103
ER -