Morphology Effect of Vertical Graphene on the High Performance of Supercapacitor Electrode

Graphene and its composites are widely investigated as supercapacitor electrodes due to their large specific surface area. However, the severe aggregation and disordered alignment of graphene sheets hamper the maximum utilization of its surface area. Here we report an optimized structure for supercapacitor electrode, i.e., the vertical graphene sheets, which have a vertical structure and open architecture for ion transport pathway. The effect of morphology and orientation of vertical graphene on the performance of supercapacitor is examined using a combination of model calculation and experimental study. Both results consistently demonstrate that the vertical graphene electrode has a much superior performance than that of lateral graphene electrode. Typically, the areal capacitances of a vertical graphene electrode reach 8.4 mF/cm2 at scan rate of 100 mV/s; this is about 38% higher than that of a lateral graphene electrode and about 6 times higher than that of graphite paper. To further improve its perfor...