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

Flexible supercapacitors (FSCs) are regarded as promising energy storage devices for portable electronic products due to their quick charging/discharging capabilities and high security. However, developing high-energy-density FSC devices using cost-effective materials and feasible manufacturing techniques remains a challenge. In this work, we propose a hierarchical metal–graphene-textile current collector to address this issue. The composite collector is made up of metal Ni electrodeposited on the surface of graphene-coated nonwoven fabric, which is further fabricated to flexible anode and cathode by electrodeposition of Co(OH)₂ and FeOOH arrays, respectively. Then, a self-standing, all solid-state asymmetric flexible supercapacitor (FSC) is developed using the flexible electrodes with alkaline potassium hydroxide/poly(vinyl alcohol) (KOH/PVA) hydrogel as a gel electrolyte. Notably, the FSC device exhibits an impressive areal capacitance of 205.2 mF cm^–2 within a working voltage window of 1.3 V, resulting in an energy density of 48.2 μWh cm^–2. Furthermore, the FSC shows outstanding cyclic and mechanical stability, retaining its initial capacitance well under various bending states. Our work presents a promising design approach for the facile and rational construction of lightweight, highly flexible, and cost-effective supercapacitors.