Thermal reduction of sulfur-containing MAX phase for MXene production

Two-dimensional (2D) MXene, as an important member of the emerging 2D nanomaterials, has received much attention in recent years, especially in energy-related fields. Unfortunately, the controllable synthesis of high-purity MXenes in a scalable way is still a challenge, due to the usual utilization of hazardous etching agents. It is highly desired that a simple, controllable, and effective approach is available for producing MXene in a green manner. In this work, an innovative thermal reduction strategy is proposed for the fabrication of MXenes from the corresponding sulfur-containing MAX phases, in which the weakly bonded S atoms react with hydrogen to form a volatile gas and leave 2D graphene-like Ti2C nanosheets. As a promising anode material for electrochemical Li+ ion storage, the resulting MXene demonstrated satisfying initial discharge capacities of ~200 mAh g−1. Furthermore, the capacity remained at ~70 mAh g−1 over 130 cycles even at a high rate of 2.0 A g−1, indicating a good rate capability and cycling stability. This work thus offers a novel approach for MXene fabrication and enriches MXene-based electrode materials for energy devices.