Graphene/carbon aerogels derived from graphene crosslinked polyimide as electrode materials for supercapacitors

Abstract

Carbon aerogels with hierarchical porous structures are highly promising for developing novel electrode materials for supercapacitors due to their substantial active sites for ion and electron transfer. Herein, a new type of graphene/carbon aerogels with multimodal pores have been facilely synthesized via carbonization of graphene crosslinked polyimide aerogels. Compared to most carbon aerogels based on organic aerogels reported previously, this preparation process is facilitated by the exclusion of harmful formaldehyde. Moreover, graphene is demonstrated as a powerful crosslinking agent, allowing acceleration of the gelation process, improvement of the porous structures inside carbon aerogels, and enlargement of specific surface area and conductivity of carbon aerogels. SEM observation shows the multimodal pores and three-dimensional nano-network of carbon aerogels, which provide short diffusion lengths for both charge and ion transport and high electroactive regions. With graphene involved, the as-prepared carbon aerogels possess high specific surface area up to 998.7 m² g⁻¹ and specific capacitance up to 178.1 F g⁻¹ at a current density of 1 A g⁻¹, which is much higher than that of pure carbon aerogels (193.6 m² g⁻¹ and 104.2 F g⁻¹). This work provides a new and facile avenue for fabricating high performance carbon aerogels with hierarchical structures and broadens the potential applications of polyimide.