In Situ Synthesis of MXene with Tunable Morphology by Electrochemical Etching of MAX Phase Prepared in Molten Salt. Issue 7 (30th December 2022) - Liu, Liyuan
Abstract: MXenes, a rapidly growing family of 2D transition metal carbides, carbonitrides, and nitrides, are one of the most promising high‐rate electrode materials for energy storage. Despite the significant progress achieved, the MXene synthesis process is still burdensome, involving several procedures including preparation of MAX, etching of MAX to MXene, and delamination. Here, a one‐pot molten salt electrochemical etching (E) method is proposed to achieve Ti2 C MXene directly from elemental substances (Ti, Al, and C), which greatly simplifies the preparation process. In this work, different carbon sources, such as carbon nanotubes (CNT) and reduced graphene oxide (rGO), are reacted with Ti and Al micro‐powders to prepare Ti2 AlC MAX with 1D and 2D tuned morphology followed by in situ electrochemical etching from Ti2 AlC MAX to Ti2 CT x MXene in low‐cost LiCl‐KCl. The introduction of the O surface group via further ammonium persulfate (APS) treatment can act in concert with Cl termination to activate the pseudocapacitive redox reaction of Ti2 CCl y O z in the non‐aqueous electrolyte, resulting in a Li + storage capacity of up to 857 C g −1 (240 mAh g −1 ) with a high rate (86 mAh g −1 at 120 C) capability, which makes it promising for use as an anode material for fast‐charging batteries or hybrid devices in a non‐aqueous energy storage application. Abstract : A one‐pot molten salt electrochemical etching (E) method is proposed to achieve Ti2 C MXene directly from elemental substances (Ti, Al, and C), which greatly simplifies the preparation process. By using carbon sources with different morphologies, such as carbon nanotubes and reduced graphene oxide, MAX and MXene with tuned morphology are prepared based on the "carbon‐template‐growth" mechanism.