Carbon aerogel spheres prepared via alcohol supercritical drying

We have developed a method that would allow for the fabrication of carbon aerogel (CA) spheres. The inverse phase suspension polymerization of resorcinol and formaldehyde monomers with Na2CO3 as a catalyst followed by supercritical drying was explored. The effects of the chemical formulation and processing procedures and the conditions of the structures of organic and related carbon aerogels were studied. The experimental results indicated that it was easy to avoid the accumulation of polymerization heat during gelation, and easy to take out the products from the reaction container, through this fabrication method. Sol-gel microspheres with diameters ranging from about 30-1000 mu m could be obtained. After drying the sol-gel spheres under alcohol supercritical drying conditions, aerogel spheres with a bulk density of 0.8-1.0 g/cm(3) were prepared, and by subsequently pyrolyzing them, CA spheres with surface areas of 250-650 m(2)/g were obtained. The resultant CA spheres could be used as the electrode materials of supercapacitors. The specific capacitance of the CA spheres was as high as 215 F/g, and the equivalent series resistance at 48 Hz was about 1 Omega. (c) 2006 Elsevier Ltd. All rights reserved.