A general Lewis acidic etching route for preparing MXenes with enhanced electrochemical performance in non-aqueous electrolyte

• Published in: Nature materials Vol. 19; no. 8; pp. 894 - 899
• Main Authors: Li, Youbing, Shao, Hui, Lin, Zifeng, Lu, Jun, Liu, Liyuan, Duployer, Benjamin, Persson, Per O. Å., Eklund, Per, Hultman, Lars, Li, Mian, Chen, Ke, Zha, Xian-Hu, Du, Shiyu, Rozier, Patrick, Chai, Zhifang, Raymundo-Piñero, Encarnacion, Taberna, Pierre-Louis, Simon, Patrice, Huang, Qing
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2020; Nature Publishing Group
• Subjects: 639/301; 639/301/299/161; 639/301/299/161/891; Aqueous electrolytes; Biomaterials; Chemical Sciences; Chemistry and Materials Science; Condensed Matter Physics; Electric power; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; Electrolytes; Energy storage; Engineering Sciences; Etching; Gallium; Material chemistry; Materials; Materials Science; Metal carbides; Molten salts; MXenes; Nanotechnology; Nitrides; Nonaqueous electrolytes; Optical and Electronic Materials; Phases; Storage capacity; Synthesis; Transition metals; Energy storage materials; Electrochemical energy storage applications; MXenes; Lewis acidic melts
• ISSN: 1476-1122; 1476-4660; 1476-4660
• DOI: 10.1038/s41563-020-0657-0

Two-dimensional carbides and nitrides of transition metals, known as MXenes, are a fast-growing family of materials that have attracted attention as energy storage materials. MXenes are mainly prepared from Al-containing MAX phases (where A = Al) by Al dissolution in F-containing solution; most other MAX phases have not been explored. Here a redox-controlled A-site etching of MAX phases in Lewis acidic melts is proposed and validated by the synthesis of various MXenes from unconventional MAX-phase precursors with A elements Si, Zn and Ga. A negative electrode of Ti 3 C 2 MXene material obtained through this molten salt synthesis method delivers a Li + storage capacity of up to 738 C g −1 (205 mAh g −1 ) with high charge–discharge rate and a pseudocapacitive-like electrochemical signature in 1 M LiPF 6 carbonate-based electrolyte. MXenes prepared via this molten salt synthesis route may prove suitable for use as high-rate negative-electrode materials for electrochemical energy storage applications. Two-dimensional transition metal carbides and nitrides, known as MXenes, are currently considered as energy storage materials. A generic Lewis acidic etching route for preparing high-rate negative-electrode MXenes with enhanced electrochemical performance in non-aqueous electrolyte is now proposed.