Fabrication of all-solid-state textile supercapacitors based on industrial-grade multi-walled carbon nanotubes for enhanced energy storage

Textile supercapacitors (TESCs) are an emerging energy storage solution to power smart gadgets integrated on clothes. Herein, efficient solid-state TESCs with different active areas (2-8 cm(2)) were produced based on cotton fabrics coated with industrial grade multi-walled carbon nanotubes (MWCNTs) as electrodes and a safe polyelectrolyte. The textile electrodes were fabricated by an optimized eco-friendly scalable dip-pad-dry process. The lowest electrical resistance (2.62 ohm cm(-2)) and most uniform coating of the electrodes were achieved using 10 mg mL(-1) CNTs dispersion and 8 dip-pad-dry steps. The TESCs exhibited a specific capacitance of 8.01 F g(-1) (9.18 F cm(-2)) and high cyclability (5000 cycles). The energy and power densities were tuned by changing the electrode area: the largest TESC presented the highest energy density of 6.30 Wh kg(-1), which was 14x higher than those of other EDLC-type carbon-based TESCs reported in the literature; the smallest TESC presented the highest power density of 2.72 kW kg(-1), being 49x higher than the values reported for comparable systems. Finally, a sensor was powered for 47 min by coupling two TESCs in series (14 cm(2)). This work demonstrated the ability to produce efficient TESCs using industrial grade MWCNTs by processes implemented in the Textile Industry, boosting technological transfer for high-tech applications.