High-performance polypyrrole coated knitted cotton fabric electrodes for wearable energy storage

High-performance polypyrrole (PPy)-coated knitted cotton fabric electrodes with good conductivity and flexibility are successfully fabricated using an improved chemical polymerization technique. The polypyrrole nanoparticles areal loading of the knitted cotton fabric electrode (10.14 +/- 0.43 mg cm(-2)) is similar to those of commercial electrodes when the molar ratio of pyrrole to oxidant (ferric trichloride hexahydrate) is equal to 2. The PPy-coated fabric electrode shows a superior areal specific capacitance (5073 mF cm(-2) at 1 mA cm(-2)) and outstanding cycling stability. The fabric-based symmetric all-solid-state supercapacitor has an enhanced areal specific capacitance of 1167.9 mF cm(-2) at 1 mA cm(-2), and the capacitance retention reaches to 77.7% when the current density increases from 1 to 20 mA cm(-2). Furthermore, it maintains close to 90% capacitance after 2000 cycles and exhibits good cycling stability. The PPy-coated fabric-based supercapacitor possesses an energy density as high as 102.4 mu Wh cm(-2) at a power density of 0.39 mW cm(-2). This work provides a simple and practical technique for transforming textiles into wearable and commercially viable energy storage devices.