Vertically Oriented Grid-like Reduced Graphene Oxide for Ultrahigh Power Supercapacitor

Graphene, as a promising electrode material, usually has limited power performance due to stacking of the graphene sheets. To solve this problem, we prepared a vertically oriented grid-like reduced graphene oxide (VrGO) with vertical channels by directional freezing, drying and annealing. Being used as supercapacitor electrodes, the VrGO membranes showed a specific capacitance of 131 F g(-1) at scan rate of 1 V s(-1). Due to the high electronic conductivity, especially the regular and straight ion diffusion channels, a very high voltage sweep rate of cyclic voltammetry (CV) 200 Vs (-1) is reached in KOH electrolyte, and therefore, a supercapacitor with an ultrahigh power density of about 740 kW kg(-1) can be obtained. The excellent power performance would open new opportunities in the fields of electrochemical energy harvesting and storage.