▎ 摘　　要

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.