Fabrication of new Mn-based MXene structure from MnO2 for electrochemical energy storage applications

Abstract

MXene compound of Mn7C3 was successfully prepared using combined mechanical, thermal, and leaching processes. A mixture of MnO2, Al, and black C with stoichiometric ratios 3:5:2 was mechanically activated in the ball mill for 5 h. Thermal treatment at 1000 °C was applied to this mixture. Magnetic separation was used to separate Mn3AlC2 from Al2O3. After that, Al was leached from Mn3AlC2 using 15% HF. SEM investigation indicated the formation of Mxene (Mn7C3) particles as aligned sheet-like structure and particle size distribution range of 110–145 nm. The obtained MXene compounds were used as an active material vs. lithium metal and assembled in a coin cell. The electrochemical assessment of this cell was carried out using galvanostatic cycling, electrochemical impedance spectroscopy, and cyclic voltammetry techniques. MXene (Mn7C3) cell showed better performance with charge capacity by preserving about 150 mAh g−1 after 100 cycles. The coulombic efficiency of the cell is approaching 99.2% after long cycles.Graphical abstract