Fluoride‐Free Synthesis of Two‐Dimensional Titanium Carbide (MXene) Using A Binary Aqueous System

Abstract Two‐dimensional (2D) titanium carbide (Ti 3 C 2 ) is emerging as an important member of the MXene family. However, fluoride‐based synthetic procedures remain an impediment to the practical applications of this promising class of materials. Here we demonstrate an efficient fluoride‐free etching method based on the anodic corrosion of titanium aluminium carbide (Ti 3 AlC 2 ) in a binary aqueous electrolyte. The dissolution of aluminium followed by in situ intercalation of ammonium hydroxide results in the extraction of carbide flakes (Ti 3 C 2 T x , T=O, OH) with sizes up to 18.6 μm and high yield (over 90 %) of mono‐ and bilayers. All‐solid‐state supercapacitor based on exfoliated sheets exhibits high areal and volumetric capacitances of 220 mF cm −2 and 439 F cm −3 , respectively, at a scan rate of 10 mV s −1 , superior to those of LiF/HCl‐etched MXenes. Our strategy paves a safe way to the scalable synthesis and application of MXene materials.