Ti3C2Tx Nanosheets/Ti3C2Tx Quantum Dots/RGO (Reduced Graphene Oxide) Fibers for an All-Solid-State Asymmetric Supercapacitor with High Volume Energy Density and Good Flexibility

By using Ti3C2Tx quantum dots as interlayer spacers, Ti3C2Tx nanosheets/Ti3C2Tx quantum dots/RGO (reduced graphene oxide) fiber (M(6)M(3)RG(1)) is prepared by a wet-spinning method; it shows good capacitance and excellent flexibility. The M(6)M(3)RG(1) fiber electrode possesses a novel network structure and a maximum volumetric capacitance of 542 F cm(-3), and its capacitance and flexibility are affected by the amount of Ti3C2Tx quantum dots. Also, the Ti3C2Tx/PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)] fiber (M7P3) is prepared by injecting a homogeneous suspension of Ti3C2Tx nanosheets and PEDOT:PSS into a bath of 98 wt % H2SO4. The M(6)M(3)RG(1) fiber is used as the positive electrode, and the M7P3 fiber is used as the negative electrode; a M(6)M(3)RG(1)//M(7)P(3 )asymmetric, flexible, solid-state supercapacitor is assembled in a PVA-H2SO4 gel electrolyte. The assembled device exhibits a volumetric capacitance of 53.1 F cm (-3) and a good cycle stability of 96.6% after 5000 cycles. It also shows outstanding flexibility and mechanical properties; for example, the volumetric capacitance has no obvious change after the device is bent at 90 degrees for 500 times. Moreover, its voltage window can be expanded to 1.5 V, and volumetric energy density of 16.6 mWh cm(-3) can be achieved. This work will open up a new application area for new wearable energy storage devices based on the Ti3C2Tx fibers.