ZnCl2-activated porous carbon spheres with high surface area and superior mesoporous structure as an efficient supercapacitor electrode

Abstract

Thanks to the unique architectural design, nanosized porous carbon materials exhibit better behavior as electrical double-layer capacitors than conventional carbon-base materials. In this work, porous carbon sphere (PCS) materials with superior porosity and uniform nanospherical morphology were successfully prepared by means of a facile chemical activation route. The analysis of pore structure and morphology of the resultant PCS were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N₂ sorption technology and electron microscope. The results indicated that this PCS material possess remarkable porosity, extremely large surface area (∼2500 m² g⁻¹), large pore volume (1.37 cm³ g⁻¹) and narrow pore distribution (2.73 nm). The well-developed mesoporous structure and high surface area benefited the PCS to exhibit an excellent charge storage capacity with a specific capacitance of 196 F g⁻¹ in 2 M KOH at a current density of 0.5 A g⁻¹ and long-term cycling stability over 1000 cycles. Compared with ordered mesoporous carbon and other porous carbon materials, PCS present an enhanced electrochemical performance, which could be attributed to its high surface area and well-developed mesoporosity, as well as its nanospherical morphology, favoring the ion accumulation on the electrode surface and facilitating fast electrolyte ion transportation.