A promising Ni-Fe double hydroxide fiber electrode for application of flexible woven-supercapacitor and wastewater decolorization

Abstract

Textile-based supercapacitors are ideal energy supply equipment for intelligent wearable products. Apart from the further enhanced energy storage property, the poor bending resistance and air permeability also compromise their electrochemical performance in practical use. Based on traditional textile technology, the supercapacitors woven by fibrous electrodes promise to combine both electrochemical and wearable performances. Herein, the carbon fiber-based Ni-Fe double hydroxide electrode (NiFe@NiFeDH/CF) with uniform morphology has been obtained through a facile route of palladium-free electroless plating coupled electrooxidation. By controlling Fe 2+ content in the plating baths, the interwoven nanosheets with small intervals and large crystal spacing could be designed, which provided low diffusion resistance for electrolyte ions and adequate active sites for energy storage. Subsequently, the all-solid-state asymmetric textile supercapacitors (wSC-NF//CY) were fabricated by weaving techniques with NiFe@NiFeDH/CF as positive electrode and carbon yarns as the negative electrode. Benefit from the better electrochemical property of NiFe@NiFeDH/CF, the wSC-NF//CY owned unexpected excellent energy storage performance that at the power density of 9.0 W cm −2 the energy density could reach 26.8 mW h cm −2 . Additionally, with the help of fabric structure, the wSC-NF//CY could be integrated into different materials to accommodate curved human bodies or other non-flat surfaces. Moreover, the NiFe@NiFeDH/CF could also be used to decolorize sewage with an electro-Fenton reaction under a small voltage. Thus, this work constituted a breakthrough on multifunctional energy storage materials and their eco-friendly and sustainable usage. • The fiber electrode was prepared by electroless plating coupled electrooxidation. • Fabric based supercapacitor with plain weave structure was obtained by weaving. • The supercapacitor owned unexpectedly excellent electrochemical performance. • The fiber electrode could also treat colored wastewater under a small voltage.