Carbon Microspheres as Supercapacitors

Abstract

Carbon microstructures fabricated by ultrasonic spray pyrolysis (USP) of aqueous precursors were tested as supercapacitors. USP carbons (USP-C) possess unique physicochemical characteristics, including substantial microporosity and high surface concentrations of oxygenated functional groups. We find that USP-Cs have higher electrochemical double-layer capacitance compared with other carbon structures. Porous carbon microspheres prepared from USP of lithium dichloroacetate, lithium/potassium propiolate, or sucrose produce electrochemical double layer capacitors (EDLCs) that have gravimetric capacitances of 185, 341, and 360 F/g, respectively. Microstructural and chemical analyses of the carbon materials suggest that the observed capacitance is related to the effects of surface functionality.