High-Yield Continuous-Flow Synthesis of Spheroidal C₆₀@Graphene Composites as Supercapacitors

Graphene spheres confining fullerene C₆₀ are quantitatively formed under high-shear and continuous-flow processing using a vortex fluidic device (VFD). This involves intense micromixing a colloidal suspension of graphite in DMF and an o-xylene solution of C₆₀ at room temperature in the absence of surfactants and other auxiliary substances. The diameters of the composite spheres, C₆₀@graphene, can be controlled with size distributions ranging from 1.5 to 3.5 μm, depending on the VFD operating parameters, including rotational speed, flow rate, relative ratio of C₆₀ to graphite, and the concentration of fullerene. An electrode of the composite material has high cycle stability, with a high areal capacitance of 103.4 mF cm^-2, maintaining its capacitances to 24.7 F g^-1 and 86.4 mF cm^-2 (83.5%) at a high scan rate of 100 mV s^-1.