Two-dimensional fluorine-free mesoporous Mo2C MXene via UV-induced selective etching of Mo2Ga2C for energy storage

As an emerging and important family of two-dimensional (2D) nanomaterials, MXene has demonstrated to be a type of promising electrode materials for energy storage devices. Hazardous fluorine-containing acids are commonly applied in exfoliation synthesis of MXenes, which bring about additional safety and environmental concerns. Herein, we proposed a novel and effective UV-induced selective etching method to fabricate fluorine-free mesoporous Mo2C MXene from Mo2Ga2C bulk ceramic in several hours. The resultant MXene exhibits a distinct 2D sheet-like structure without much contamination of impurity ions. When the as-synthesized Mo2C MXene is explored as potential anode materials for rechargeable batteries, excellent rate capability and cycling stability are achieved for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Furthermore, the assembled flexible Mo2C MXene-based batteries manifested excellent capacity retentions under bending states. Therefore, this Mo2C MXene has great potential for practical energy storage applications. This innovative approach can be further developed for fabricating other MXenes from UV-sensitive precursors.