Reduced graphene oxide-linked stacked polymer forests for high energy-density supercapacitor

Hierarchical nanostructured materials consisting of stacked polymer nanowires forests interconnected by monolayer graphene sheets were fabricated through bottom-up nanofabrication. Driven by external voltage, aniline molecules and graphene oxide were alternatively assembled for hierarchical porous stacked nanostructures while graphene oxide was in-situ reduced to graphene during the assembly process. Scanning electron microscopy and atomic force microscope results indicated that monolayer graphene sheets served as the transition nodes for the neighboring nanowire arrays. As-produced hierarchical nanostructures were used as supercapacitor electrodes, and stack-dependent device properties were discovered. In the organic electrolyte, specific energy density was increased and power density was maintained as the stack of forests increased at each scan rate. The specific energy density of as-produced supercapacitors was as high as 137. Wh/Kg while the power density was 1980. W/Kg. Further analysis found that the distinctive energy-storage behavior originated from the electrode/electrolyte interactions and the dependence on the diffusion and charge transferring process. This work pointed out a simple pathway to tailor electrode architecture for supercapacitors with both high energy density and high power density.