Co-Fe layered double hydroxides nanosheets vertically grown on carbon fiber cloth for electrochemical capacitors

Abstract

We demonstrate the fabrication of a core-shell structure composite of Co–Fe layered double hydroxides (LDHs) on the surface of carbon fiber cloth (CFC). The Co–Fe LDHs nanoplates are vertically anchored onto the surface of electrical conductive CFC via a simple hydrothermal process followed by an I2 oxidation process. The hexagonal Co–Fe LDHs nanoplates on the surfaces of carbon fibers form a porous network film. The carbon fibers with high conductivity can act as conductive cores to support a large number of Co–Fe LDHs nanoplates to deliver a high specific capacitance of 774 F g−1 at the current density of 1 A g−1. An assembled asymmetric capacitor by using Co–Fe LDHs-CFC as positive electrode material and activated carbon as negative electrode material can deliver an energy density of 16.1 Wh kg−1 at the power density of 399.7 W kg−1 with a good cycling stability. This study provides a way to combine Co–Fe LDHs with carbon materials to obtain a composite that can deliver an improved performance for electrochemical capacitor application.