We reported a one-step in-situ electrochemical route to synthesize 3D aerogel electrode materials
including graphene and hexagonal CeO2 composites. The graphene/CeO2 aerogel can be formed via
freeze-drying graphene/CeO2 colloidal solution that was obtained by electrochemical exfoliation of
graphite anode and in-situ deposition of CeO2 nanoparticles on graphene sheets in mixing electrolyte
of (NH4)2SO4/Ce(NO3)3 and (NH4)2SO4/(NH4)2Ce(NO3)6. The as-obtained CeO2 nanoparticles were closely
contacted with graphene, which can enhance the synergistic effect between graphene and CeO2. It is
interesting that the as-obtained CeO2 products possessed hexagonal crystal structure that was rarely
reported. The Faradaic reactivity of the graphene/CeO2 composites as supercapacitor was enhanced with
the increase of the concentration of Ce salts in initial electrolyte. The introduction of CeO2 to graphene
electrode can lead to the presence of additional pseudocapacitance besides the electric double-layer
capacitance. This simple one-step in-situ electrochemical route can be extended to synthesize various
graphene/metal oxide aerogel electrode materials for electric energy storage.