Smart Integration of Cobalt-Based Metal Organic Framework with Textile Waste for a Sustainable and Flexible High-Performance Supercapacitor

Abstract

With the advancement of electronic devices and wearable electronics, the concern for green energy solutions is rising. Energy generation from waste would be exciting among various sustainable resources since it can reduce costs and simultaneously eliminate waste generation. Here, we report a straightforward method for turning waste cotton textiles into a flexible free-standing supercapacitor. The waste cotton cloth-derived CoCo₂O₄@NCC-30 (cobalt oxide@nitrogen-doped carbon cloth) electrode possesses a large specific surface area (∼415.5 m² g^–1) and good flexibility. CoCo₂O₄ integration and N-doping provide abundant active sites to augment the electrode storage capacity. In a three-electrode system with an aqueous 2 M KOH electrolyte, the resulting CoCo₂O₄@NCC-30 electrode exhibits an exceptional specific capacitance of 924.7 F g^–1 at a current density of 1 A g^–1. It displays excellent cycling stability over 10,000 cycles. The symmetric supercapacitor with CoCo₂O₄@NCC-30 electrodes and a cotton cloth separator achieves a specific capacitance of 362.64 F g^–1 at 0.8 A g^–1. A flexible symmetric full-cell supercapacitor with a PVA-KOH gel electrolyte shows an energy density of 16.3 Wh kg^–1 at 0.6 A g^–1. Moreover, the CoCo₂O₄@NCC-30-based full-cell supercapacitor maintains a stable performance under bending, showcasing its flexibility and mechanical integrity. This work highlights the design of a green supercapacitor for high-performance flexible and wearable energy storage.