The construction of carbon nanofiber composites modified by graphene/polypyrrole for flexible supercapacitors

Carbon nanofibers (CNFs) have attracted considerable attention because they make it possible for materials to have a variety of enhanced properities. However, the unsatisfied electrochemical performance of an individual component and the poor electrical conductivity caused by insufficient physical contact points become the fully addressing issues when CNFs are proposed as electrode material in a flexible supercapacitor. Hence, this paper proposes a feasible perspective on enhancing the electrochemical performance and flexibility via the method of electrostatic self-assembly and the "dipping and drying" strategy. The reduced graphene oxide (rGO) layer is uniformly anchored on the surface of SnCl2 modified carbon-based fiber polyacrylonitrile (PAN) fabricated by the electrospinning method. Pseudocapacitance material polypyrrole (PPy) is subsequently deposited and selected to design a composite [email protected]@PPy electrode. As expected, the as-constructed binder-free [email protected]@PPy electrode shows a specific capacitance of 203 F g−1; the assembled flexible supercapacitor delivers a high energy density of 15 Wh kg−1 together with a power density of 500 W kg−1, and displays remarkable cycling stability after 10,000 cycles. Finally, the flexibility via various deformations is discussed, meanwhile, the structural and compositional stability of the [email protected]@PPy electrode during long-term cycling test are demonstrated. In light of the facile preparation strategy and the excellent electrochemical performance, this work offers an instructive direction for the development of flexible energy storage devices.