General and Fast Gas-Solid Synthesis of Functional MXenes and Derivatives on the Scale of Tens of Grams

Abstract

The rising of MXenes not only enriches the two-dimensional material family but also brings more opportunities for diverse functional applications. However, the controllable synthesis of MXenes is still unsatisfied via the common liquid-solid etching route, considering the unsolved problems like safety risk, time cost and easy oxidation. Herein, a facile yet efficient gas-solid (G-S) reaction methodology is devised by using hydrogen fluoride gas derived from fluorinated organics as the MAX etchant toward high-efficiency fabrication of multiple MXenes and their derivatives. The innovative G-S reaction strategy exhibits superb versatility to achieve different gram-level MXenes (V2C, Ti3C2, Nb2C, Ti2N, Ti3CN, (Mo2/3Y1/3)2C) in a very short time, and even realizes in-situ heteroatom doping or synchronous phase conversion of MXenes directly from MAX phases. The obtained MXenes and their derivatives exhibit excellent structure stability and high electron/ion conductivity, making them promising materials for electrochemical applications. In particular, the N-doped V2C MXene shows superior adsorption and catalytic activity toward lithium polysulfides for advanced lithium sulfur batteries.

Keywords: Fast kinetics; Gas-solid reaction; In-situ doping/conversion; MXenes; lithium sulfur batteries.