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

Abstract

Two‐dimensional (2D) titanium carbide (Ti3C2) 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 (Ti3AlC2) in a binary aqueous electrolyte. The dissolution of aluminium followed by in situ intercalation of ammonium hydroxide results in the extraction of carbide flakes (Ti3C2Tx, 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.

A Facile, High‐Yield, and Freeze‐and‐Thaw‐Assisted Approach to Fabricate MXene with Plentiful Wrinkles and Its Application in On‐Chip Micro‐Supercapacitors

“…The calculated yield was 81.4%. Figure c summarizes several previously reported preparation methods with their yield, flake size, and thickness . There are many factors to influence the yield like the etch process, intercalation agent, and the conditions of sonication and centrifugation.…”

“…Therefore, recently, increasing research efforts are being devoted to the synthesis of MXene. For example, by means of electrochemical etching in a binary aqueous electrolyte, the yield of single‐ or double‐layer MXene can reach more than 90% . Note that the value of yield (>90%) is the percentage of single‐ or double‐layer MXene among all the dispersed MXene rather than the weight ratio of the dispersed MXene to m‐MXene.…”

Surface Modified MXene‐Based Nanocomposites for Electrochemical Energy Conversion and Storage

“…Therefore, the careful selection of electrolyte is a critical factor for the electrochemical synthesis of MXene materials. Recently, Feng's group reported the selective electrochemical etching of Al atoms from Ti 3 AlC 2 ( Figure ) . On account of the strong binding capability of Cl − with Al, an aqueous solution consisting of 1.0 m ammonium chloride (NH 4 Cl) and 0.2 m TMAOH with a pH value >9 was chosen as the electrolyte.…”

“…a) Schematic of the etching and delamination process; b) The configuration of electrochemical cell; c) Optical image of the as‐received bulk Ti 3 AlC 2 ; d) The aqueous dispersion of delaminated Ti 3 C 2 T m (0.15 mg mL −1 ); e) X‐ray diffraction patterns of Ti 3 AlC 2 , Ti 3 C 2 T m , and Ti 3 C 2 T m film. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…j) The electrochemical etched Ti 3 C 2 T m powder. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”