Electrochemical performance of polydopamine modified PANI/rGO composites: Dependency on preparation sequence

Compounding polyaniline (PANI) and reduced graphite oxide (rGO) is a fascinating cost-effective way to combine the high energy density of faradic material and high power density of carbonaceous material. In this study, in-situ polymerization of dopamine was used to reduce graphite oxide and to modify the rGO product with polydopamine (PDA) simultaneously. This modification prevented restacking of rGO, and enhanced the interactions between PANI and rGO. The partial reduction of GO during the polymerization of dopamine was proven by X-ray diffraction, Fourier transform infrared attenuated total reflectance, and UV-vis spectroscopy. Surprisingly, the electrochemical performance of the composites depends strongly on the preparation sequence. PANI/(rGO-PDA) composites obtained by the synthesis of PANI in the presence of rGO-PDA show better electrochemical performance than (PANI/rGO)-PDA composites, which were produced by polymerizing dopamine in the presence of PANI/GO composite. At a given scan rate of 20 mV s(-1), the highest specific capacity of PANI/(rGO-PDA) composites was 230.7 F g(-1), which was higher than those of all (PANI/rGO)-PDA composites. This phenomenon is tightly related to the differences in morphologies, conductivities and specific surface areas of the two types of composites.