Fabrication of 3D graphene microstructures with uniform metal oxide nanoparticles via molecular self-assembly strategy and their supercapacitor performance

Abstract

Metal oxide nanoparticles equipped graphene with outstanding performance display broad application. Compared with graphene sheets loaded nanoparticles, such 3D architecture not only has the intrinsic performance of 2D graphene and nanoparticles, but also provides advanced functionality in many aspects. Up to now, many strategies have been explored to construct 3D graphene hybrids. However, the application of extra agents and/or agglomeration nanoparticles has a detrimental impact on particle applications. Herein, we present a molecular self-assembly strategy for producing high-quality 3D graphene microstructures with uniform metal oxide (ZnO) nanoparticles by directly deriving 3D amphiphilic Zn(MAA)2 precursors with a well-layered structure into 3D graphene hybrid. Notably, the organic part of organized Zn(MAA)2 molecules play a structurally crucial function in the formation of the graphene layers. It not only guides the ordered self-assemblies, but also facilitates the rapid in-situ formation of graphene structures by generating lots of allyl radicals in the heating process. Meanwhile, during the formation of graphene layers, ZnO NPs generated from carboxylate groups of Zn(MAA)2 molecules penetrate into the graphene. The as-obtained ZG-500 HSs as supercapacitor electrode displays a specific capacitance of 272.1 F g−1 at 1 A g−1. In addition, an asymmetric supercapacitor based on ZG-500 HSs and activated carbon provides an energy density of 13.4 Wh kg−1 at the power density of 387.5 W kg−1. This novel strategy opens up a potential and green route to high quality 3D graphene hybrids for supercapacitor.