Few-layered Ti3C2Tx MXenes coupled with Fe2O3 nanorod arrays grown on carbon cloth as anodes for flexible asymmetric supercapacitors

Abstract

The design of flexible electrodes with high areal capacitance is the key for the application of flexible asymmetric supercapacitors (ASCs) in portable and wearable electronics. In this study, Ti₃C₂T_x MXene coupled with the Fe₂O₃/CC flexible negative electrode, with good conductivity, high areal capacitance, and excellent flexibility, was fabricated by a simple dipping method, in which the as-grown Fe₂O₃ nanorod arrays on carbon cloth were dipped into the few-layered MXene nanosheet solution repeatedly to make the Fe₂O₃/CC fibers wrapped with MXene completely. The MXene@Fe₂O₃/CC electrode presents a remarkable areal capacitance of up to 725 mF cm⁻² at a current density of 1 mA cm⁻² which was contributed by both MXene and Fe₂O₃ nanorods. As to the MXene layer, it not only offers capacitance for the flexible electrode, but also provides fast and efficient ion/electron transport pathways for Fe₂O₃ to effectively improve electronic conductivity. Besides, the as-constructed ASC devices consisting of MXene@Fe₂O₃ and MnO₂ electrodes achieve a high energy density of 1.61 mW h cm⁻³ at a power density of 22.55 mW cm⁻³ along with good stability. The work provides a simple effective strategy to load active materials on carbon fibres and to construct hierarchical coating-structured electrodes for high-performance flexible ASC application.