Nano-sized metal-doped carbon aerogel for pseudo-capacitive supercapacitor

Carbon aerogel was prepared by polycondensation of resorcinol with formaldehyde using sodium carbonate as a catalyst in ambient conditions. Nano-sized Ni-doped carbon aerogel was then prepared by a precipitation method in an ethanol solvent. In order to elucidate the effect of Ni content on electrochemical properties, nano-sized Ni-doped carbon aerogels with different Ni content (21, 35, 60, and 82 wt%) were prepared and their performance for pseudo-capacitive supercapacitor electrode was investigated. Electrochemical properties of nano-sized Ni-doped carbon aerogel electrodes were measured by cyclic voltammetry at a scan rate of 10 mV/s and charge/discharge test at constant current of 1 A/g in 6 M KOH electrolyte. Among the samples prepared, 35 wt% nano-sized Ni-doped carbon aerogel (Ni/CA-35) showed the highest capacitance (120 F/g) and excellent charge/discharge behavior. The enhanced capacitance of nano-sized Ni-doped carbon aerogel was attributed to the faradaic redox reactions of nano-sized Ni oxide. On the basis of this result, ca. 35 wt% Co-, Cu-, Fe-, and Mn-doped carbon aerogels were also prepared by a precipitation method. Among the nano-sized metal-doped carbon aerogels, Mn-doped carbon aerogel (Mn/CA-34) showed the highest capacitance (141 F/g).