Hybrid fibers assembled from MoSe₂/graphene heterostructures endow improved supercapacitive performance

Fiber supercapacitors (FSCs) that fulfill the necessities of high power/energy density, flexibility, robustness, and wearing comfort are prospective power sources for portable/wearable electronics. The efforts in this field remain to exploit high performance fibrous materials with combined advantages of suitable mechanical properties, high electrical conductivity, and enhanced specific capacitance. Herein, for the first time, we incorporate expanded molybdenum diselenides (MoSe₂) into graphene fibers via the assistance of ethylenediamine. The presence of MoSe₂ enables the as-fabricated hybrid fiber a 2.2-fold enhancement in volumetric capacitance (148.6 F cm⁻³) as well as good rate performance. The assembled FSC provides a capacitance of 22.8 F cm⁻³, an energy density of 1.2 mWh cm⁻³, and a maximum power density of 314.0 mW cm⁻³ in addition to excellent cycle stability. Notably, the flexible and mechanically steady FSCs display excellent processability under well-controlled conditions, including weaving into the fabric, and their electrochemical properties maintain unchanged under various bending angles. Furthermore, the FSCs are connected to steadily power LED lamp, illustrating the promising possibility as future wearable energy storage devices.