Preparation and Characterization of Reduced Graphene Oxide-Bismuth Oxide composites for Supercapacitor Electrodes

Reduced graphene oxide- bismuth oxide (rGO-Bi2O3) composites were prepared at various weight ratios by the improved Hummer's method. During the process, the mixed solutions were prepared, then, rGO was obtained by hydrothermal... [ view full abstract ]

Reduced graphene oxide- bismuth oxide (rGO-Bi₂O₃) composites were prepared at various weight ratios by the improved Hummer's method. During the process, the mixed solutions were prepared, then, rGO was obtained by hydrothermal method. Finally, the complex of rGO-Bi₂O₃ was prepared by calcination after hydrothermal treatment. The results show that the remove of oxygen- containing functional groups in rGO are increase as the increase of graphene agglomeration, and the Raman shifts wave-number of G band tending to the lowest. When the weight ratio of GO to bismuth nitrate at 1: 0.6, the G band wave-number of rGO-Bi₂O₃ is the highest, and the stripping effect of graphene is the best. The electrochemical characteristics of rGO and rGO-Bi₂O₃ were also examined in 1 M KOH electrolyte. The results showed that the dominated charge storage mechanisms of them are attributed to the electric double layer behaviors. Studied by CV curves, the content of bismuth nitrate is increased, and rGO-Bi₂O₃ has a higher capacitance. The rGO capacitance is 84.6 F/g, and the rGO-Bi₂O₃ at 1: 1.2 exhibits a maximum capacitance of 196 F/g at 1 A/g. By EIS analysis, rGO-Bi₂O₃ shows lower impedance compared to rGO, exhibiting a better capacitance behavior.