The self-assembly of shape controlled functionalized graphene–MnO2 composites for application as supercapacitors

Graphene–MnO2 nanocomposites with different morphologies were obtained by a facile self-assembly method. The formation mechanism of graphene–MnO2 composites with different shapes of MnO2 is discussed in detail. Nanostructured MnO2 with different morphologies was distributed on the surface of graphene uniformly. The prepared graphene–MnO2 composites could be used as electrode materials for supercapacitors. The graphene–MnO2 (flowerlike nanospheres) composite (405 F g−1) exhibited better capacitive performance than that of the graphene–MnO2 (nanowires) composite (318 F g−1) at a current density of 1.0 A g−1. The synergistic effect of graphene and MnO2 endowed the composite with high electrochemical capacitance. Moreover, the graphene–MnO2 (flowerlike nanospheres) composite showed a fast charge–discharge process and high cyclic stability.