Polyaniline/carbon nanotube nanocomposite electrodes with biomimetic hierarchical structure for supercapacitors†
Polyaniline (PANI)/multi-walled carbon nanotube (MWNT) nanocomposite films with three-dimensional architectures on the surface were prepared using fresh plant leaves as a template through the nanocasting technique. The biomimetic surface morphology of the PANI nanocomposite electrodes, including multiscale papilla-like and nanoscale texture, were successfully replicated from Xanthosoma sagittifolium leaves. The morphology, roughness and dispersed MWNTs of the PANI/MWNT nanocomposites were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and atomic force microscopy. It was found that the well-dispersed MWNTs and the multiscale morphology formed a uniform nanocomposite, with an observed larger surface area, high specific capacitance and good cycling stability during the charge–discharge process. A specific capacitance as high as 535 F g−1 at a current density of 1 A g−1 was achieved for a 5 wt% MWNT loading coupled with the high roughness of the PANI nanocomposite, and the capacitance was maintained with the increment of the current density to 3 A g−1. These easily fabricated PANI nanocomposite electrodes show great potential for energy storage applications.