A Solid-State Wire-Shaped Supercapacitor Based on Nylon/Ag/Polypyrrole and Nylon/Ag/MnO₂ Electrodes

In this work, a novel wire-shaped supercapacitor based on nylon yarn with a high specific capacitance and energy density was developed by designing an asymmetric configuration and integrating pseudocapacitive materials for both electrodes. The nylon/Ag/MnO₂ yarn was prepared as a positive electrode by electrochemically depositing MnO₂ on a silver-paste-coated nylon yarn. Additionally, PPy was prepared on nylon/Ag yarn by chemical polymerization firstly to enlarge the surface roughness of nylon/Ag, and then the PPy could be easily coated on the chemically polymerized nylon/Ag/PPy by electrochemical polymerization to obtain a nylon/Ag/PPy yarn-shaped negative electrode. The wire-shaped asymmetric supercapacitor (WASC) was fabricated by assembling the nylon/Ag/MnO₂ electrode, nylon/Ag/PPy electrode and PAANa/Na₂SO₄ gel electrolyte. This WASC showed a wide potential window of 1.6 V and a high energy density varying from 13.9 to 4.2 μWh cm⁻² with the corresponding power density changing from 290 to 2902 μW cm⁻². Meanwhile, because of the high flexibility of the nylon substrate and superior adhesion of active materials, the WASC showed a good electrochemical performance stability under different bending conditions, suggesting its good flexibility. The promising performance of this novel WASC is of great potential for wearable/portable devices in the future.