Enhanced capacitive performance of polyaniline on hydroquinone-functionalized three-dimensional porous graphene substrate for supercapacitors

Three-dimensional porous graphene/polyaniline (3D-G/PANI) electrode materials were fabricated with hydroquinone-functionalized three-dimensional porous graphene (3D-G) as the substrate. To obtain 3D-G/PANI, the functionalized 3D-G substrate was synthesized through a hydrothermal method first, and then, polyanilines (PANIs) were grown onto the skeleton of functionalized 3D-G substrate by the in situ polymerization of aniline (An). The effect of An amount was optimized to improve the electrochemical performance of 3D-G/PANI. The results of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy and infrared spectroscopy reveal that functionalized 3D-G was successfully prepared and PANIs were uniformly grown on the skeleton of functionalized 3D-G in the form of nanoparticles. The 3D-G/PANI prepared with 80 μL of An exhibits a highest specific capacitance of 542 F/g at 1.5 mA/cm² (1.14 A/g), 2.05 and 1.54 times those of functionalized 3D-G and PANI, respectively. And the 3D-G/PANI retains a specific capacitance of 435 F/g even at 30 mA/cm² (22.73 A/g). Moreover, the capacity retention is 82% of initial specific capacitance after 3000 charge/discharge cycles, which is much higher than that of PANI (62%) after 1000 cycles.