Eco-Friendly Conductive Cotton-Based Textile Electrodes Using Silver- and Carbon-Coated Fabrics for Advanced Flexible Supercapacitors

Wearable electronics need the execution of electronic functions, especially on a flexible and wearable sheet substrate. In this regard, cotton textiles are widely considered as environmentally friendly and natural fiber materials, including for soft and breathable clothing. Previously, conductive cotton-based textiles were successfully fabricated through different methods, and the surface sheet resistance was found to be <15 Ω, which shows effective electrical conductivity. Nevertheless, they still need to improve mainly because of the poor electrical conductivity. In this work, conductive cotton textile electrodes with superior bending ability are judiciously fabricated by mixing conductive silver (Ag) powder into a textile ink with various carbon sources such as activated carbon (AC), graphene, and carbon nanotubes (CNTs), which can work as flexible supercapacitor electrodes. Among the three different carbon materials, the AC-based conductive cotton electrodes exhibit superior electrochemical performance in alkaline electrolyte (6 M potassium hydroxide (KOH)). The results of cyclic voltammetry (CV) reveal that areal specific capacitances as high as 3288 and 2695 mF/cm² were achieved at scan rates of 5 and 10 mV/s, respectively, for the appropriate proportion of 0.3 g of Ag with 0.15 g of AC (0.3 Ag–AC-0.15). It also exhibits excellent cyclic stability with a high capacitance retention of ∼130% for over 10 000 cycles. Moreover, a symmetric flexible supercapacitor device was also successfully fabricated in the lab scale using a poly­(vinyl alcohol) (PVA)–KOH gel electrolyte system, demonstrating that noteworthy rate performance and flexibility can be achieved for the advanced flexible energy-storage devices.