Two-dimensional carbides and nitrides of transition metals, known as MXenes, are a fast-growing family of 2D materials that draw attention as energy storage materials. So far, MXenes are mainly prepared from Al-containing MAX phases (where A = Al) by Al dissolution in F-containing solution, but 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 Ti3C2 MXene material obtained through this molten salt synthesis method delivers a Li+ storage capacity up to 738 C g-1 (205 mAh g-1) with high-rate performance and pseudocapacitive-like electrochemical signature in 1M LiPF6 carbonate-based electrolyte. MXene prepared from this molten salt synthesis route offer opportunities as high-rate negative electrode material for electrochemical energy storage applications.
@article{arxiv.1909.13236,
title = {A general Lewis acidic etching route for preparing MXenes with enhanced electrochemical performance in non-aqueous electrolyte},
author = {Youbing Li and Hui Shao and Zifeng Lin and Jun Lu and Per O. A. Persson and Per Eklund and Lars Hultman and Mian Li and Ke Chen and Xian-Hu Zha and Shiyu Du and Patrick Rozier and Zhifang Chai and Encarnacion Raymundo-Piñero and Pierre-Louis Taberna and Patrice Simon and Qing Huang},
journal= {arXiv preprint arXiv:1909.13236},
year = {2019}
}