Preparation a highly sensitive and flexible textile supercapacitor based on lignin hydrogel and polyaniline@carbon cloth composites

The flexible textures are prominent candidates for wearable devices with energy storage and high sensitive sensor properties. This paper proposed a method for preparing a flexible textile supercapacitor with the displacement sensor property, which consisted of lignin hydrogel as the semi-solid electrolyte and polyaniline@carbon cloth as the flexible electrode. A series of lignin hydrogels with different cross-linking degrees, which were employed as the semi-solid electrolyte, were prepared by using kraft lignin and polyethylene glycol diglycidyl ether as a crosslinking agent. It is shown that the compressive strength (0.196 MPa) and water retention capacity (92.9 %) of the lignin-based hydrogel could be greatly improved by adjusting the cross-linking degree of the hydrogel. Furthermore, the textile supercapacitor was assembled by using polyaniline@carbon cloth as the flexible electrode with lignin hydrogel. The electrochemical tests show that the hydrogel supercapacitor has good ionic conductivity and rate capability, maintaining a high capacitance (200.3 F·g−1) and coulomb efficiency after 6000 cycles. Meanwhile, it shows good sensitivity and stability in both pressure and bending sensing tests, and has the potential to become a new generation of flexible materials.