A Supercapacitor Electrode Synthesis Strategy: Proton Acid‐Treated Ti 3 C 2 T X Film with Single‐walled Carbon Nanotubes as a Reinforcement

High‐performance electrode materials are the key to advances in the energy storage area. 2D transition metal carbide Ti 3 C 2 T X is the most widely studied MXene with a unique two‐dimensional structure, exhibiting excellent electrochemical properties and becoming a new choice electrode material for supercapacitors in many studies However, the poor mechanical properties of pure the Ti 3 C 2 T X film has become the bottlenecks for the application. Ti 3 C 2 T X with less Li + was prepared by proton acid colloid treatment, and then the single‐walled carbon nanotubes (SWCNTs) were used as interlayer barriers in the films to prevent Ti 3 C 2 T X layers from restacking to prepare Ti 3 C 2 T X and SWCNTs composite films. The composite films were tested and analyzed by different electrochemical techniques. The results showed that the film formed by MXene colloidal filtration after proton acid treatment was denser and the electrical conductivity reached 608700 S/m, which was 3.2 times higher than that of the original Ti 3 C 2 T X film. The composite film was prepared by mixing MXene colloidal proton acid treatment and SWCNTs, followed by filtration showd good capacitive capacity, reaching 270.5 F/g by testing in the 1 m H 2 SO 4 electrolyte with the CV cycle of 5 mV/s. And the specific capacitance retention reaches 97.6 % under 5000 CV cycles. The tensile test of composite film shows that the ultimate strength up to 50.3 MPa, which is about 2.3 times compared to original Ti 3 C 2 T X film.