High-performance MnO2@MXene/carbon nanotube fiber electrodes with internal and external construction for supercapacitors

As interest in smart textiles grows, fiber-based supercapacitors are gaining attention as promising devices for powering wearable electronics. Herein, we have demonstrated a two-step manufactured hybrid fiber with excellent energy storage properties. Anhydrous MXene (Ti3C2Tx) sheets are primarily spun in synergy with liquid crystal carbon nanotubes (CNTs) to produce a continuous fiber as a promising electrode material, which solves the problem of poor rate capability owing to the sheet re-stacking of MXene. MnO2@MXene/CNT fibers are subsequently prepared by electrochemical deposition with controlled time. The optimal content of MXene (10 wt%) and a perfect thickness of the MnO2 layer (4 μm) are testified to achieve an excellent capacitance of 371.1 F cm−3 in three-electrode system, which is about 200% and 1800% higher than that of 10 wt%-MXene/CNT and CNT fiber electrode, respectively. Symmetric fiber supercapacitor is assembled by paralleling two fibers with LiCl/PVA gel electrolyte, manifesting a superior cycling stability of 86.3% after 10000 cycles. Anhydrous MXene nanosheets and CNTs are incorporated by a high yield spinning technique to prepare continuous hybrid fibers as a conductive framework for MnO2 deposition, exhibiting stable and outstanding energy storage properties in supercapacitor.