Ti3C2Tx MXene/carbon composites for advanced supercapacitors: Synthesis, progress, and perspectives

MXenes are a family of two-dimensional (2D) layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas, excellent electron conductivity, good hydrophilicity, and tunable terminations. Among various types of MXenes, Ti3C2Tx is the most widely studied for use in capacitive energy storage applications, especially in supercapacitors (SCs). However, the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites. To overcome such challenges, carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties. This review introduces the common strategies used for synthesizing Ti3C2Tx, followed by a comprehensive overview of recent developments in Ti3C2Tx/carbon composites as electrode materials for SCs. Ti3C2Tx/carbon composites are categorized based on the dimensions of carbons, including 0D carbon dots, 1D carbon nanotubes and fibers, 2D graphene, and 3D carbon materials (activated carbon, polymer-derived carbon, etc.). Finally, this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs.