Polydopamine surface modification facilitates high specific capacitance in reduced graphene oxide aerogel

Abstract

Graphene, with its high specific surface area and excellent electrical conductivity, is regarded as an ideal electrode material for supercapacitors. However, its smooth and hydrophobic surface limits its electrochemical performance. In this study, graphene oxide (GO) was utilized to prepare graphene aerogel (GA), constructing a three-dimensional structure, and polydopamine (PDA) was introduced to enhance its surface properties. Although the introduction of PDA slightly decreased the specific surface area, the numerous hydrophilic groups it introduced improved wettability and provided sites for the adsorption of electrolyte ions, thereby significantly enhancing the performance of the aerogel in supercapacitors. At a current density of 0.5 A/g, the polydopamine-modified graphene aerogel (PDGA) exhibited an ultra-high specific capacitance of 564.06F/g, surpassing the theoretical specific capacitance of graphene at 550F/g and significantly outperforming previously reported carbon-based materials. The symmetric supercapacitor based on PDGA achieved an areal capacitance of 459.62 mF/cm² at 0.5 mA/cm², maintaining a retention rate of 92.7 % after 10,000 cycles, demonstrating its superior performance and cycle stability. Furthermore, the strategy of modifying surfaces with PDA can also be applied to improve the specific capacitance of other carbon materials, such as carbon nanotubes, potentially serving as a universal method for enhancing the electrode performance.