MXene/PVA Fiber-based Supercapacitor with Stretchability for Wearable Energy Storage

MXene fiber-based supercapacitor exhibits a great potential for wearable energy storage devices with a large surface area, good conductive, and higher power density. However, MXene flakes are difficult to spin independently due to the non-liquid crystal structure. In the report, we fabricated freestanding MXene/PVA fibers with good stretchability and impressive electrochemical properties for fiber-based supercapacitors by a simple wet spinning method. The tensile strength of the MXene/PVA fibers is significantly enhanced compared with pure PVA fibers for the concentration of MXene for around 5-20 wt.%. The elongation of the MXene/PVA fiber can reach 48 %, even if the MXene concentration increase to 25 wt.%. MXene flakes also increase the thermal stability of hybrid fibers compared with pure PVA fibers. MXene/PVA fiber-based supercapacitors act as efficient energy storage devices, which display high gravimetric capacitance (119.3 F g(-1)), and areal capacitance (130.9 mF cm(-2)), strong durability in multiple mechanical states, and steady electrochemical behavior after stretching.