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-Ti 3 C 2 T x ) are synthesized by selectively etching M n+1 AX n 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-Ti 3 C 2 T x ) 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-aTi 3 C 2 T x and d-D-Ti 3 C 2 T x 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-Ti 3 C 2 T x (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.