Textile-based flexible copper sulfide electrode via low-temperature all-solution process for electrochemical capacitor

Abstract

Flexible supercapacitors (FSCs) have attracted significant interest in accordance with the rapid development of wearable electronic devices. One of the most promising ways of facilitating flexible devices is the utilization of textile substrates. However, to realize the applicability of textile substrates, coating adhesive conduction layers and capacitively active electrode materials is strongly required on the textile substrate. The deposition of those layers usually requires the further heat treatment, which can physically damage polymer and cloth-based textile substrates. Therefore, finding an effective way to construct those layers without thermal and physical damages to the textile substrate during the fabrication process has remained challenging. In this work, two-dimensional copper sulfide (CuxS) nanoflake arrays were directly synthesized on a commercially available conductive Ni–Cu fabric (CSF/Ni–Cu) via a simple low-temperature all-solution process. This method can maintain the original flexible characteristics and durability of the conductive textile substrate, implying the high possibility of mass production and industrialization. The optimized CSF/Ni–Cu electrodes yielded an excellent gravitational capacitance of 3263 F/g and 453.2 mAh/g at 1 mA/cm2 current density and an outstanding cycling stability of 97.2% over 10,000 charge–discharge cycles, verifying their superior electrochemical performance. The integrated textile-based solid-state flexible asymmetric supercapacitors (T-FASCs) successfully powered the multi-arrays of light-emitting diode and a mobile phone, demonstrating the practical feasibility of the textile supercapacitors with the CSF/Ni–Cu electrode.