Flexible fiber-shaped supercapacitors with high energy density based on self-twisted graphene fibers

In this research, self-twisted graphene fibers are successfully prepared by a simple method. The assembled self twisted graphene fiber exhibits excellent mechanical properties, the elongation is up to 26.3% and the tensile intensity reaches up to 244.8 MPa, which is higher than that of the previously reported graphene fibers. Based on the remarkable mechanical properties of self-twisted graphene fibers, the flexible fiber-shaped supercapacitors are fabricated. The fiber-shaped supercapacitor demonstrates outstanding flexibility, even at the knotted state the capacitance is very stable. Furthermore, the fiber-shaped supercapacitor exhibits excellent supercapacitive performance with high energy density (25.5 mWh cm(-3)) and long-term cycling stability, retaining 91% of the capacitance over 10,000 cycles. The outstanding performances of flexible fiber-shaped supercapacitors indicate the self-twisted graphene fibers have promising applications in portable and flexible energy storage devices.