Potentiostatically synthesized flexible polypyrrole/multi-wall carbon nanotube/cotton fabric electrodes for supercapacitors

A polypyrrole (PPy)/multi-walled carbon nanotube (MWCNT)/cotton flexible electrode for high-performance supercapacitors was fabricated by a facile two-step method, including MWCNT-coated cotton prepared by a facile “dip and dry” method and then subjected to the electro-deposition of PPy by a potentiostatic deposition technique. The effects of deposition potential, time, and molar ratio of p-toluenesulfonic acid to pyrrole (Py) on the properties of textile electrodes were studied. The sheet resistances and surface morphologies of the as-prepared composite fabrics obtained under different conditions were investigated by means of a four-point probe method and field-emission scanning electron microscope and the electrochemical performances of the PPy/MWCNT/cotton electrodes were evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy measurements. These composite fabrics exhibited outstanding flexibility, high conductivity, with sheet resistance of 6.0 ± 0.4 Ω sq⁻¹, a cauliflower structure with small holes on the surface favoring the contact between the electrode active material, a specific capacitance of 535 F g⁻¹ (maintaining 97.8 % after 100 cycles), and a fitting value of charge-transfer resistance of 13.9 Ω cm⁻², which offers great promise in wearable energy storage device applications because of their low-cost and high-performance features.