Waste to Wealth: Upcycling Waste Toner into Magnetic Fe₃O₄ and Conducting Polymer Hybrids for Enhanced Energy Storage Application

Printers generate electronic waste in the form of used ink cartridges, which has an impact on resources such as plastics and precious metals. Toner metal oxide repurposed for supercapacitors could save valuable materials. Figuring out the optimal electrolyte concentration, on the other hand, is critical for optimizing supercapacitor performance and increasing energy/power density. This paper investigates the characteristics of waste toner-derived Fe₃O₄ and its composite with two conducting polymers, i.e., polyaniline (PANI) and polypyrrole (PPy) as electrode materials. With studies performed in 2 M, 4 M, and 6 M KOH electrolyte, a comparative analysis is made to understand the effect of electrolyte concentration on supercapacitor performance linked to the enhanced performance. The highest specific capacitance was achieved in 4 M KOH electrolyte which was calculated to be 319 F/g and 286 F/g at 10 mV/s composite synthesized with PPy and PANI, respectively, in a three-electrode assembly. The supercapacitor device performed well in terms of energy density and power density when tested in a Swagelok cell assembly. These outcomes offer significant insights into the potential of waste-derived materials for sustainable energy devices, implying a promising future for energy storage applications. Graphical Abstract: (Figure presented.)