Free-standing flexible graphene-based aerogel film with high energy density as an electrode for supercapacitors

• Published in: Nano materials science Vol. 3; no. 1; pp. 68 - 74
• Main Authors: Yuan, Shijia, Fan, Wei, Jin, Yanan, Wang, Dong, Liu, Tianxi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2021; KeAi Communications Co., Ltd
• Subjects: Aerogel film; Graphene; N-doping; Polypyrrole; Supercapacitor; Supercapacitor; Graphene; Aerogel film; N-doping; Polypyrrole
• ISSN: 2589-9651; 2589-9651
• DOI: 10.1016/j.nanoms.2020.03.003

Two-dimensional graphene film exhibits sluggish ion diffusivity while three-dimensional (3D) graphene aerogel has low packing density and poor mechanical flexibility. Consequently, there is an urgent need for graphene-based film with both mechanical robustness and high specific capacitance. Here, we present an easy and scalable strategy for fabricating a free-standing flexible graphene-based aerogel film electrode with a two-layered structure, in which the top layer is an interconnected macroporous reduced graphene oxide/carbon nanotube (RGO/CNT) aerogel, and the bottom layer is a flexible electrospun polyacrylonitrile (PAN) nanofiber membrane. The porous 3D structure of the aerogel provides fast transport of electrolyte ions and electrons, while the nanofiber membrane provides both strong support for the aerogel and mechanical flexibility. Polypyrrole (PPy) can be uniformly loaded on RGO/CNT/PAN (RCP) composite aerogel film to provide pseudocapacitance, and nitrogen-doped RGO/CNT/carbon nanofiber (NRCC) aerogel film can be obtained by further pyrolysis. The resultant RCP@PPy-0.05//NRCC based asymmetric supercapacitor can have a maximum voltage of 1.7 V and a maximum energy density of 60.6 W h kg−1 at 850.2 W kg−1. This indicates that free-standing graphene-based aerogel film can be used in flexible supercapacitors.