Lightweight Flexible Solid-State Supercapacitor Based On Metal-Graphene-Textile Composite Electrodes

Flexible supercapacitors (FSCs) areregarded as promisingenergystorage devices for portable electronic products due to their quickcharging/discharging capabilities and high security. However, developinghigh-energy-density FSC devices using cost-effective materials andfeasible manufacturing techniques remains a challenge. In this work,we propose a hierarchical metal-graphene-textile current collectorto address this issue. The composite collector is made up of metalNi electrodeposited on the surface of graphene-coated nonwoven fabric,which is further fabricated to flexible anode and cathode by electrodepositionof Co(OH)(2) and FeOOH arrays, respectively. Then, a self-standing,all solid-state asymmetric flexible supercapacitor (FSC) is developedusing the flexible electrodes with alkaline potassium hydroxide/poly(vinylalcohol) (KOH/PVA) hydrogel as a gel electrolyte. Notably, the FSCdevice exhibits an impressive areal capacitance of 205.2 mF cm(-2) within a working voltage window of 1.3 V, resultingin an energy density of 48.2 & mu;Wh cm(-2). Furthermore,the FSC shows outstanding cyclic and mechanical stability, retainingits initial capacitance well under various bending states. Our workpresents a promising design approach for the facile and rational constructionof lightweight, highly flexible, and cost-effective supercapacitors.