Intercalation and delamination of two-dimensional MXene (Ti3C2Tx) and application in sodium-ion batteries

The initial multilayer-structure two-dimensional transition metal carbide MXene (as-Ti3C2Tx) are synthesized by selectively etching Mn+1AXn in HF, and the surface of MXene adhere to some functional groups. Intercalation and delamination by ultrasonication in alcohol or DMSO (dimethyl sulfoxide) produce less lamellar structure of resultant (d-Ti3C2Tx) and change the surface circumstance. This fabricated fewer-sheets samples not only improve the electrical conductibility, specific area, but also reduce the ion diffusion resistance. Meanwhile, the d-aTi3C2Tx and d-D-Ti3C2Tx show outstanding capacity of 110 or 120 mAh g−1 at 100 mA g−1 with coulombic efficiency of about 95%, which lead to 26% increase compared with as-Ti3C2Tx (95 mAh g−1) for sodium-ion batteries, and remarkable capacitance retention of 84.5% or 85.8% after cycles for in alcohol and DMSO, respectively.