3.3 V customizable, recyclable, and remanufacturable flexible symmetric supercapacitors

Abstract

We successfully fabricated a customizable, recyclable, and remanufacturable nanocomposite flexible symmetric supercapacitor (FSSC) comprising vanadium oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/water-based polyurethane (WPU)/nanoclay (VPWN). In this study, WPU was employed as a multifunctional component in both the nanocomposite electrodes and electrolytes, contributing to excellent rate capabilities and cycle performances. The VPWN FSSCs were fabricated in various customizable morphologies, including fibrous, film-like, and three-dimensional (3D) structures, and underwent performance tests alongside recyclability analyses for device remanufacturing. Among these, the 3D VPWN FSSC incorporating a WPU–LiClO₄–acetamide solid electrolyte exhibited the highest specific capacitance (121 F/g at 1 A/g) and energy density (183 Wh/kg at 600 W/kg), as well as demonstrated exceptional static cyclability (< 9% loss after 5000 cycles). The energy storage mechanism of the FSSCs during charge–discharge cycles was elucidated using in situ X-ray absorption spectroscopy. Notably, remanufactured VPWN (RVPWN) FSSCs, produced from recycled materials, retained over 75% of the performance of the original VPWN FSSCs. Furthermore, these remanufactured devices demonstrated remarkable cycling stability, with a capacity retention rate exceeding 93% even after 5000 cycles, outperforming commercial SCs. The results highlight a green and sustainable approach for repurposing discarded energy storage materials, offering a simple, cost-effective recycling process. This study underscores the feasibility of integrating recycled materials into new device fabrication, bridging the gap between academia and industry to advance sustainable and environmentally friendly energy storage technologies.