Unsorted PostconsumerPlastic Waste in Energy ConversionUsing Piezoelectric, Triboelectric, and Pyroelectric Generation Mechanisms

This study investigates the energy-harvesting potential of unsorted postconsumer plastic packaging waste through piezoelectric, triboelectric, and pyroelectric regimes. The waste included typical commodity polymers such as high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). When employed as contact layers of nanogenerators, heterogeneous waste plastic blends demonstrated the ability to convert mechanical and thermal inputs into electrical energy, facilitated by physical contacts among plastics and mechanical deformation of processing additives in plastics as well as temperature gradients. Significant results include output voltage values above 130 V, short-circuit current density, and charge density of 50 ± 2 μAcm^–2 and 390 ± 21 nCm^–2, respectively, obtained for the triboelectric pair of PET bottle film and the blend of PS/HDPE/PP enriched with 60 wt % of PET. Furthermore, the so-called rejected recyclable plastic waste, which is a residual fraction of plastic waste still largely landfilled, generated output voltages above 60 V when paired with a PET bottle in triboelectric device. These findings reveal that unsorted plastic waste has a promising capacity for energy harvesting, indicating its potential for use in sustainable energy applications.