Two dimensional holey carbon nanosheets assisted by calcium acetate for high performance supercapacitor

Abstract

Nanostructured carbon materials are the first preference for fabricating electrodes as they have intrinsic conductivity, excellent chemical stability and high surface area. In this report, a novel two dimensional (2D) holey carbon nanosheet was prepared by pyrolysis of a composite of resorcinol–formaldehyde resin (RF) and calcium acetate (CA), followed by acid etching and base activation. The results reveal that CA plays a crucial role in the formation of the 2D holey carbon nanosheet. The CaO originated from the decomposition of CA was found not only to act a template for the holes, but a catalyst for the graphitic carbon. The obtained carbon nanosheet exhibited uniformly distributed holes with an average diameter of 60 nm. The hierarchical micro/mesoporous structure has a high surface area of 1258.2 m2 g−1, which is great for the fabrication of electrode materials in supercapacitor. It delivered a specific capacitance of 360.1 F g−1 at the current density of 1.0 A g−1 in 6.0 M KOH solution. Furthermore, a two-electrode symmetric supercapacitor based on the carbon material displayed an energy density of 13.3 Wh kg−1 at a high power density of 7125 Wkg–1. The supercapacitor also showed superior rate capability, cycle stability and great potential for use in practical applications.