Interconnected binary carbon hybrids for supercapacitor electrode

Currently, main bottlenecks plaguing the electrochemical performance of carbon supercapacitor are the low electrical conductivity and poor electrolyte ion-accessible surface area of carbon active materials in the fabricated electrodes. Herein, novel interconnected binary carbon hybrids with the high electrical conductivity of ∼300 S/cm and the efficient electrolyte ion-accessible surface area are prepared and applied in the active electrodes of carbon supercapacitor. It is demonstrated that, during the templated growth process of large-sized micro-sheet carbon (MSC, >10 μm in lateral size), a part of carbon nanotubes (CNTs) grow on nano-apophysises embedded on the surfaces of SiO2 particles, leading to the interconnected binary carbon hybrids. Due to the strong structural binding between the MSC and CNTs, the synergetic effect derived from MSC and CNTs greatly enhances the electrical conductivity and improves the electrolyte ion diffusion in the assembled supercapacitor with the binary carbon hybrids. An electrode using the interconnected carbon hybrids as active materials shows a highly admirable specific capacitance of 210 F/g at an initial high current density of 3 A/g, a high rate capability with 90.5% capacitance retention at the high current density of 50 A/g, and only loses 1.9% capacitance after 10000 cycles at the current density of 3 A/g. Remarkably, the supercapacitor displays the energy density and power density of 18.2 Wh/kg and 37.4 kW/kg at the current density of 3 A/g, respectively.