2,2,6,6-Tetramethylpiperidin-1-oxyl-Oxidized Cellulose Nanofibers Reinforced MXene Fiber with Superior Capacitance...

MXene fibers, characterized by their high capacitance and conductivity, hold significant promise as electrode materials for wearable supercapacitors (SCs) in the field of textile electronics. Nevertheless, the inherent brittleness of pure MXene fibers stems from the dense stacking and weak interactions between the MXene flakes. This work presents a strategy to improve the mechanical robustness and electrochemical performance of MXene fibers through the incorporation of 2,2,6,6-tetramethylpiperidin-1-oxyl-oxidized cellulose nanofibers (TO-CNFs) via a wet-spinning technique. The MXene/TO-CNF composite fibers showed expanded interlayer spacing and enhanced interfacial interactions, resulting in a specific capacitance of 264.4 F g^-1, a tensile strength of 162 MPa, and outstanding cyclic durability (exhibiting 90.5% capacitance retention following 10,000 charge-discharge cycles). Additionally, when assembled into solid-state fiber-based supercapacitors (FSCs), these composite fibers show excellent flexibility, featuring a high energy density of 6.4 Wh kg^-1 and a specific capacitance of 90.8 F g^-1, facilitating practical applications such as powering a light-emitting diode (LED) and digital meter.