Functionalizing PAN Carbon Nanofibers Using Ti₃C₂T_x MXene for Improved Thermal and Electrochemical Behavior

Electrospinning and dip coating are well-established and highly effective methods to incorporate 2D Ti₃C₂T_x MXene flakes into nanofibers. The synergies exhibited between MXene and carbonized nanofiber (CNF) networks significantly enhance nanofiber performance in energy and environmental applications, demanding further investigation into MXene incorporation strategies. This study systematically evaluates different strategies for incorporating MXene flakes into electrospun polyacrylonitrile (PAN) fibers under consistent processing conditions, followed by an investigation into the thermal and electrochemical behavior of the resulting CNF mats. The first strategy incorporates MXene into the electrospinning solution, creating a uniform dispersion within the resultant nanofiber. In the second approach, MXene is deposited onto the mat via dip coating, while the third approach combines both methods, searching for synergies through enhanced distribution and surface functionalization. All mats were thermally stabilized at 260°C and subsequently carbonized at 900°C. Thermogravimetric analysis was employed to evaluate the thermal stability of the mats throughout the pre and post-carbonization processes. The MXene coating approach reduced mat shrinkage, leading to an increased carbon yield after carbonization, while incorporating MXene directly into the nanofiber solution provided the highest CNF flexibility. The third approach achieved the highest MXene loading, enhancing electrical conductivity and pseudocapacitive performance.