Morphology Effects on the Supercapacitive Electrochemical Performances of Iron Oxide/Reduced Graphene Oxide Nanocomposites

The benzyl alcohol route is used to decorate reduced graphene oxide (RGO) nanosheets with iron oxide (FeOx) nanoparticles. The resulting FeOx/RGO composites combine both electrical double‐layer capacitive and pseudocapacitive behaviors of RGO and FeOx, respectively, owing to the hybrid nanostructure. In 1  M Na 2 SO 4 aqueous electrolyte, the capacitance of the FeOx/RGO electrode reaches 126 F g −1 in a negative potential range from −0.8 to 0.0 V (vs. Ag/AgCl) and 97 F g −1 in the extended potential window from −0.8 to +0.7 V (vs. Ag/AgCl). By using the benzyl alcohol route, a higher concentration of iron precursor leads to full surface coverage of the RGO nanosheets by smaller FeOx nanoparticles, forming a close‐packed layer that limits the restacking of RGO nonosheets in the dry state. The resulting FeOx/RGO composite gains the same power capability as RGO and a higher energy density than raw FeOx, owing to this well‐designed morphology,.