Transforming invasive weeds into energy solutions: water hyacinth-based hybrid electrodes for green supercapacitors

The excessive proliferation of <i>Eichhornia crassipes</i> (water hyacinth) poses significant environmental challenges; however, its abundant biomass offers a sustainable solution for energy storage applications. This study presents an eco-friendly approach to fabricating high-performance supercapacitor electrodes using water hyacinth-derived activated carbon (WH), polypyrrole (PPy), and titanium dioxide (TiO₂). The WH-TiO₂/PPy hybrid electrode was synthesized <i>via</i> hydrothermal treatment and interfacial polymerization, ensuring a resource-efficient and environmentally responsible process. The composite exhibited a high gravimetric capacitance of 610 F g^-1 at 0.5 A g^-1 in 3 M KOH, with excellent cycling stability (94% retention after 5000 cycles). An asymmetric supercapacitor with WH-TiO₂/PPy as the positive electrode and activated carbon as the negative electrode delivered an energy density of 98 W h kg^-1 and a power density of 5606 W kg^-1. This work highlights the potential of transforming invasive biomass into cost-effective, high-performance energy storage materials, advancing the principles of green chemistry through waste valorization and sustainable material design.