Flexible supercapacitors based on a ternary composite of polyaniline/polypyrrole/graphite on gold coated sandpaper

Highlights: • A flexible and cost-effective supercapacitor based on sand paper, pencil graphite and conducting polymers was produced. • The combination of polyaniline and polypyrrole produced a supercapacitor with a superior energy and power density. • This work presents a new approach for an easy and rapid prototyping of flexible supercapacitor. • The produced flexible supercapacitor preserved its function over mechanical deformation. Developing low-cost and efficient flexible supercapacitors is an important step towards the production of new energy storage systems for efficient wearable electronic devices. In this work, we report a simple and cost-effective approach to produce flexible electrodes for supercapacitors. The system consists of a complex ternary structure of hierarchical polyaniline (PAn) assembled on a polypyrrole (PPy) layer deposited on graphite pencil traces (Grt) in sandpaper. The proposed ternary composite PAn-PPy-Grt-Sp assembled in a device offered a maximal areal capacitance of 55.35 mF cm^-2 at 0.3 mA cm⁻², a higher value when compared to its counterparts of PAn-Grt-Sp (31.8 mF cm⁻²) and PPy-Grt-Sp (19.75 mF cm⁻²). The ternary composite also exhibited a higher energy (4.92 μWh cm⁻²) and power density (87.09 μW cm⁻²) at a current density of 0.3 mA cm⁻² producing a more equilibrated supercapacitor device. The response to mechanical efforts returned negligible variation in electrochemical properties while cyclability remains as 80% of initial value after 3000 cycles.