Layered Nanofiber Yarn for High-Performance Flexible All-Solid Supercapacitor Electrodes

High-performance yarn-shaped supercapacitor electrode materials are lightweight, compact, flexible, and low cost, making them ideal for developing flexible energy storage devices. In this paper, a low-cost and large-scale manufacturing method to build high-performance supercapacitor yarn electrodes was proposed. To construct a new polypyrrole (PPy)/PAN/cotton yarn electrode, the solution jet spinning technique was used to prepare PAN nanofiber-wrapped cotton core yarns; in situ polymerization was used to deposit PPy nanoparticles to prepare a high-performance yarn electrode, and flexible all-solid supercapacitors were assembled. The synergistic effect caused by the unique electrode structure greatly improves the electrochemical performance. The supercapacitor had a maximum area ratio capacitance of 341.67 mF cm–2 (37.60 F cm–3) at a current density of 0.87 mA cm–2. The maximum energy density was 0.047 mWh cm–2 at a power density of 4.32 mW cm–2. Supercapacitors had outstanding electrochemical stability and flexibility, which has broad application prospects in wearable smart textiles.