LAUSR

Porous electrodes with nanosheets vertically aligned to the substrate are candidates for high power energy storage applications such as rechargeable batteries and electrochemical capacitors due to the shortened ion and electron transfer pathway. Here we fabricate vertically aligned reduced graphene oxide (rGO) films by combining electrophoretic deposition and ice template methods. As deposited and freeze-dried films prepared from graphene oxide dispersion show perpendicular orientation of graphene oxide with a tilt angle of 85 ± 9° with respect to the substrate. The film thickness and pore sizes are varied from 50 to 200 μm and from 10 to 100 μm, respectively, by changing the freeze-drying conditions. The vertical alignment of nanosheets enhances the specific capacitance and charging rate behavior. At a high scan rate of 500 mV s–1, the specific capacitance was approximately 78% of that at 2 mV s–1, indicating an improvement in the rate performance due to the perpendicular orientation.