Titanium Carbide Mxene Shows an Electrochemical Anomaly in Water-In-Salt Electrolytes
Titanium carbide MXene shows an electrochemical anomaly in water-in-salt electrolytes Xuehang Wang,a Tyler S. Mathis,a Yangyunli Sun,b Wan-Yu Tsai,c Netanel Shpigel,d Hui Shao,e Danzhen Zhang,a Kanit Hantanasirisakul,a Fyodor Malchick,d,f Nina Balke,g De-en Jiang,b Patrice Simon,e Yury Gogotsia* a A. J. Drexel Nanomaterials Institute, and Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA. b Department of Chemistry, University of California, Riverside, California 92521, USA. c Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. d Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel e Materials Science Department - CIRIMAT, Université Toulouse III Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France. f Center for physical and chemical methods of research and analysis, al-Farabi Kazakh National University, 050040 Almaty, Kazakhstan. g Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA. 1 KEYWORDS: Titanium carbide MXene, water-in-salt electrolytes, desolvation-free cation insertion, abnormal electrochemical behavior ABSTRACT: Identifying and understanding charge storage mechanisms is important for advancing energy storage, especially when new materials and electrolytes are explored. Well- separated peaks in cyclic voltammograms (CVs) are considered key indicators of diffusion- controlled electrochemical processes with distinct Faradic charge transfer. Herein, we report on an electrochemical system with separated CV peaks, accompanied by surface-controlled partial charge transfer, in 2D Ti3C2Tx MXene in water-in-salt electrolytes. The process involves the insertion/desertion of desolvation-free cations, leading to an abrupt change of the interlayer spacing between MXene sheets.
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