A novel method to fabricate discrete porous carbon hemispheres and their electrochemical properties as supercapacitors

Abstract

A simple and efficient method to produce discrete, hierarchical porous carbon hemispheres (CHs) with high uniformity has been successfully developed by constructing nanoreactors and using low crosslinked poly(styrene-co-divinylbenzene) (P(St-co-DVB)) capsules as precursors. The samples are characterized by scanning and transmission electron microscopy, Fourier transform infrared and Raman spectroscopy, X-ray diffraction, and N₂ adsorption and desorption. Considering their application, the cyclic voltammetry and electrochemical impedance spectroscopy characterization are tested. The experimental results show that the achievement of discrete and perfect carbon hemispheres is dependent on the proper amount of DVB in the P(St-co-DVB) capsules, which can contribute to the ideal thickness or mechanical strength of the shells. When the amount of DVB is 35 wt% in the precursors, a high Brunauer–Emmett–Teller surface area of 676 m² g⁻¹ can be obtained for the carbon hemispheres, and the extremely large pore volume of 2.63 cm³ g⁻¹ can also be achieved at the same time. The electrochemical test shows the carbon hemispheres have a higher specific capacitance of ca. 83 F g⁻¹ at 10 mV s⁻¹, compared to other carbon materials. So this method supplies a platform to extend the fabrication field of carbon materials and supplies more chances for the application of carbon materials including carbon hemispheres that are important components and substrates for supercapacitors.