Fluoride-Free Synthesis of 2D Titanium Carbide (MXenes) Assisted by scCO₂ -Based Ternary Solution

2D MXene-Ti₃ C₂ T_x holds great promise in various electronic applications, especially for electromagnetic interference (EMI) shielding devices and supercapacitors. Ti₃ C₂ T_x synthesis typically involves the use of hazardous fluorine-containing chemicals that can result in the formation of inert fluoride functional groups on the surface of Ti₃ C₂ T_x , severely degrading its properties and posing a threat to the performance of electron transfer among electrical devices. Herein, a supercritical carbon dioxide-based ternary solution (scCO₂ /DMSO/HCl) to produce fluoride-free Ti₃ C₂ T_x in mild conditions (via 0.5 m HCl, 20 MPa, 32 °C) is reported. The fluorine-free Ti₃ C₂ T_x films electrode presents an excellent gravimetric capacitance of 320 F g^-1 at 2 mV s^-1 in 1 m H₂ SO₄ . Besides, it is demonstrated that fluorine-free Ti₃ C₂ T_x films exhibit outstanding EMI shielding efficiency of 53.12 dB at 2.5 µm thickness. The findings offer a mild and practical approach to producing fluoride-free Ti₃ C₂ T_x and open opportunities for exploring MXenes' potential applications in various fields.