Self-assembly of monodisperse starburst carbon spheres into hierarchically organized nanostructured supercapacitor electrodes

We report a three-dimensional (3D) porous carbon electrode containing both nanoscale and microscale porosity, which has been hierarchically organized to provide efficient ion and electron transport. The electrode organization is provided via the colloidal self-assembly of monodisperse starburst carbon spheres (MSCSs). The periodic close-packing of the MSCSs provides continuous pores inside the 3D structure that facilitate ion and electron transport (electrode electrical conductivity ∼0.35 S m^-1), and the internal meso- and micropores of the MSCS provide a good specific capacitance. The capacitance of the 3D-ordered porous MSCS electrode is ∼58 F g^-1 at 0.58 A g^-1, 48% larger than that of disordered MSCS electrode at the same rate. At 1 A g^-1 the capacitance of the ordered electrode is 57 F g^-1 (95% of the 0.24 A g^-1 value), which is 64% greater than the capacitance of the disordered electrode at the same rate. The ordered electrode preserves 95% of its initial capacitance after 4000 charging/discharging cycles.