Synthesis of Ti 2 B 2 Cl x MBenes in Molten Salts From Theoretical and Experimental Perspectives

The unique properties and application possibilities of two‐dimensional (2D) materials motivate the exploration of different nanolaminated compounds. Here, by using a molten salt approach, we selectively etch Ti 2 InB 2 with ZnCl 2 to produce a multilayer (ml) Ti 2 B 2 Cl x MBene. Upon etching, indium atoms are completely removed from the precursor and replaced by chlorine surface terminations with a coverage of 1.1 < x < 1.4. Further, in situ x‐ray diffraction indicates a direct biphasic transformation from Ti 2 InB 2 to ml‐MBene, with no signs of intermediate phase formation. A computational framework based on density functional theory further corroborates these experimental observations by showing a negative reaction free energy for the formation of ml‐MBene, favourable over all competing processes. In addition, A‐element substitution into the 3D Ti 2 ZnB 2 phase is predicted to be endergonic, consistent with the absence of experimental evidence for its formation. Initial Li‐ion battery performance evaluation showed a stable discharge capacity similar to or better than MAX phases and other borides. Altogether, the theoretical framework combined with materials synthesis and characterization provides a general approach for 2D materials development, for further expansion of the family of 2D materials.