Layered MoxBy (MBenes) derived by a molten-salt method and their application in advanced LIB anodes

Abstract

As novel two-dimensional materials, MBenes derived from bulk ternary metal borides (MAB phase) have attracted increasing attention but are limited by their preparation strategy. In this work, Mo_xB_y (MBene) derivatives with an accordion-like structure were successfully prepared by completely etching an Al layer from MoAlB via a molten-salt method. The thermal behaviors, crystal structure, and surface chemical state were analyzed using DSC/TG, XRD and XPS analyses, respectively. The micro-morphology of the obtained MBene was then characterized using scanning electron microscopy and transmission electron microscopy accompanied by EDS mappings. The results reveal that the MBene synthesized at 620 °C (abbreviated as MBene-620) demonstrates its characteristic (020) peak and layered structure. When used as an advanced anode for Li-ion batteries (LIBs), the MBene delivers excellent electrochemical performances with a reversible specific capacity of 638.2 mA h g⁻¹ after 100 cycles at a current density of 0.1 A g⁻¹. As a promising green strategy, this molten-salt method provides a new opportunity to explore the wide-ranging applications of MBene series, particularly in new energy fields of LIBs.