Graphene-Containing Carbon Aerogel Prepared Using Polyethyleneimine (PEI)-Modified Graphene Oxide (GO) for Supercapacitor: Effect of Polyethyleneimine-Modified GO Content

Graphene-containing carbon aerogel was prepared by a sol–gel polymerization of resorcinol-formaldehyde (RF) method using polyethyleneimine (PEI)-modified chemically exfoliated graphene oxide (GO), and its electrochemical performance as an electrode for supercapacitor was examined. The effect of PEI-modified GO content on the physicochemical and electrochemical properties of graphene-containing carbon aerogel was investigated. For comparison, graphene-free carbon aerogel was also prepared. Among the samples, graphene-containing carbon aerogel prepared using 45 wt% PEI-modified GO solution (CA(45PG)) showed the highest BET surface area (784 m²/g) and the largest pore volume (1.71 cm³/g) with well-developed porous structure. Electrochemical properties of graphene-containing carbon aerogel and graphene-free carbon aerogel electrodes were measured by cyclic voltammetry, charge/discharge test, and electrochemical impedance spectroscopy in 6 M KOH electrolyte. Various electrochemical measurements revealed that CA(45PG) showed the highest specific capacitance (261 F/g), the lowest equivalent series resistance (0.16 Ω), and superior capacitive behavior. It is concluded that PEI-modified GO content served as an important factor determining the physicochemical properties and supercapacitive electrochemical performance of graphene-containing carbon aerogel.