Highly oxidation resistant and organic dispersible ligand functionalized MXene for triggering performance of lithium ion batteries

Abstract

Two-dimensional (2D) MXenes are one of the leading members of materials science due to their exceptional dispersion in water, metal-like conductivity, and promising applications in interdisciplinary fields. However, the ease of oxidation and poor dispersion in organic solvents have hindered the advancement of MXenes for futuristic applications. In this study, we developed oxidation-resistant, organic dispersible, environmentally stable, and conductive Ti3C2Tx MXene (Tx = –OH, –O, –F, etc.) by surface modification with 2-Ethylhexyl phosphate (EHP) ligand via a simple condensation reaction at room temperature by optimizing the pH value. The EHP functionalized MXene (MXene-EHP) has excellent dispersion stability in most organic solvents due to EHP ligands favoring excellent compatibility with counterparts. The MXene-EHP/lithium iron phosphate (LiFePO4, LFP) composite was prepared and investigated as an efficient cathode in lithium ion batteries (LIBs). The surface modification with EHP has impeded the surface oxidation of the MXene in MXene-EHP and enhanced the compatibility with the LFP cathode and ionic diffusion in LIBs. MXene-EHP/LFP has delivered an excellent specific capacity of 150 mAh g−1 and 136 mAh g−1 at the initial cycle and after the 500th cycle at 1C rate, respectively in comparison to the bare LFP electrodes with a specific capacity of 118 mAh g−1 and 101 mAh g−1.