Enhancement of supercapacitive performance of carboxymethyl cellulose-derived porous carbon monoliths by the addition of carbon nanotubes

Abstract

In this study, a simple and eco-friendly fabrication strategy for the preparation of porous carbon monoliths with 3-dimensional conductive networks was demonstrated. Porous carbon/carbon nanotube composite monoliths (PCCMs) with large specific surface area and hierarchical pore structures were prepared via eco-friendly ice-templating followed by carbonization. The resulting PCCMs showed excellent electrochemical performance due to their well-developed hierarchical porosity and high electrical conductivity following the addition of 1-D carbon nanotubes. In a 3-electrode configuration, the PCCM-derived electrode delivered a specific capacitance of 240 F g−1 at 1 A g−1. In a practical application, the PCCM-based symmetric capacitor exhibited the specific capacitance of 47.0 F g−1, rate capability of 72.7%, power density of 9.5 kW kg−1 and a cycling stability of ∼100% after 20,000 cycles, respectively. These results suggested that the PCCMs can be applied as an active material for high-performance electrical double-layer capacitors.